Prof. Richard Johnson - 'Nature Wants Us To Be Fat - Part 1'

00:43:18
https://www.youtube.com/watch?v=gAjC_BWMElk

Résumé

TLDRDr. Rick Johnson, a professor of medicine, introduces his research on a biologic switch that he asserts underpins the current obesity epidemic. Throughout a series of talks, he plans to discuss his findings, based on his book "Nature Wants Us to Be Fat." Johnson explores how animal behaviors, historical dietary changes, and biochemical processes contribute to obesity and related diseases like diabetes and hypertension. He highlights the role of fructose—a sugar prevalent in fruit and table sugar—as a trigger for a biologic switch that tricks the body into storing fat. He illustrates this mechanism using laboratory studies and highlights a genetic mutation affecting humans' fructose metabolism, emphasizing the role of uric acid in this process. Johnson argues that understanding this switch could revolutionize obesity prevention and treatment. Future discussions will delve into specific foods that activate this switch and its impact on conditions such as cancer and dementia.

A retenir

  • 🧬 Dr. Rick Johnson introduces a biologic switch driving obesity.
  • 📚 His insights are based on his book "Nature Wants Us to Be Fat."
  • 🥭 Fructose plays a critical role in activating this switch.
  • 🔵 Uric acid is a key factor in this metabolic pathway.
  • 🧠 Insulin resistance is part of the survival mechanism.
  • ⏳ The mutation affecting uric acid dates back millions of years.
  • 🍇 Animals use fructose for survival; humans consume excessively.
  • 💡 Understanding this can aid in preventing and treating obesity.
  • 🌍 Historical dietary shifts have influenced obesity trends.
  • 🧪 Future talks will cover foods that activate this switch further.
  • 🦠 Other diseases beyond obesity, like cancer, may be affected.
  • 📉 Lowering uric acid could mitigate some negative effects.

Chronologie

  • 00:00:00 - 00:05:00

    Dr. Rick Johnson introduces himself as a medicine professor sharing a discovery about a biological switch underlying obesity. The series of talks will explain the switch's discovery, its activation by foods, and its effects beyond obesity. He discloses his efforts to clinically apply his research through a small company, despite some controversies in the scientific community.

  • 00:05:00 - 00:10:00

    Johnson provides historical context about obesity, indicating a sharp rise since 1900. He notes the correlation between obesity, diabetes, hypertension, and other metabolic disorders, emphasizing the need to find underlying causes rather than solely relying on treatment advancements. He highlights the metabolic syndrome, a constellation of symptoms often accompanying obesity, such as systemic inflammation and high uric acid.

  • 00:10:00 - 00:15:00

    While past theories suggested obesity results from overconsumption and inactivity, Johnson points out that some animals purposefully gain weight for survival, indicating a controlled mechanism. This regulatory mechanism prompts animals to safely manage weight until specific conditions necessitate fat accumulation, such as survival during food shortages.

  • 00:15:00 - 00:20:00

    Johnson shifts focus to fructose, a sugar prevalent in fruits and significant historically and evolutionarily. He explains its connection to a biological switch in weight gain, proposing that fructose consumption disrupts energy balance, leading to increased fat storage. Historical animal studies showed metabolic changes parallel to human obesity when consuming fructose.

  • 00:20:00 - 00:25:00

    Beyond simple taste affinity, Johnson explores the metabolic effects of fructose, particularly in mice, observing obesity and metabolic syndrome features without taste influence. He hypothesizes fructose metabolism, rather than taste, triggers these effects, thereby suggesting that a metabolic pathway is responsible for increased fat storage and reduced energy expenditure.

  • 00:25:00 - 00:30:00

    Johnson delves into fructose metabolism, discussing its unique effects on the body. He details a non-caloric pathway linked to uric acid production, contributing to energy imbalance by decreasing ATP levels, driving hunger and fat storage. The uric acid produced by fructose metabolism impacts cellular energy, simulating starvation states that push weight gain.

  • 00:30:00 - 00:35:00

    Johnson presents a thrifty gene hypothesis, noting historical mutations affecting uric acid breakdown, increasing sensitivity to fructose. These genetic changes, beneficial for survival during past famines, now lead to heightened obesity and diabetes risk, due to elevated uric acid levels. As fructose intake has increased, these inherited traits have become detrimental.

  • 00:35:00 - 00:43:18

    Johnson concludes that while fructose from added sugars is a primary factor in obesity, natural fruits pose minimal risk due to their composition. He promises future discussions on endogenous fructose production mechanisms. Despite the genetic predisposition, he emphasizes that lifestyle changes could mitigate disease risks associated with fructose consumption.

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Carte mentale

Mind Map

Questions fréquemment posées

  • What is the main topic of Dr. Rick Johnson's presentation?

    The main topic is a biologic switch Dr. Rick Johnson believes drives obesity, its discovery, and implications for diseases beyond obesity and diabetes.

  • What book is Dr. Rick Johnson's talk based on?

    Dr. Rick Johnson's talk is based on his book "Nature Wants Us to Be Fat."

  • What potential diseases beyond obesity and diabetes does the switch affect?

    Beyond obesity and diabetes, the switch may affect diseases like cancer and dementia.

  • What historical perspective does Dr. Johnson discuss related to obesity?

    He discusses how obesity began around 1900 and aligns with the increase of sugar consumption and mutations that occurred millions of years ago.

  • What is the role of uric acid in obesity according to Dr. Johnson?

    Uric acid is associated with the biologic switch that promotes obesity by affecting energy levels in cells and driving insulin resistance.

  • Why are humans more sensitive to fructose?

    Humans are more sensitive to fructose due to a mutation that occurred millions of years ago, which affects the breakdown of uric acid.

  • How does Dr. Johnson relate fructose to obesity?

    Dr. Johnson relates fructose to obesity by explaining it activates a switch causing the body to gain weight through various metabolic pathways.

  • How do animals use fructose differently from humans?

    Animals use fructose to store fat as a survival mechanism during food scarcity, whereas humans today consume it in excess, leading to obesity.

  • Will there be more discussions on this topic?

    Yes, future talks will discuss foods that activate the switch and how it relates to other diseases.

  • How is insulin resistance a survival response?

    Insulin resistance allows more glucose to remain in the blood for critical organs like the brain during food shortages.

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  • 00:00:01
    [Music]
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    [Music]
  • 00:00:13
    hello i'm dr rick johnson uh i'm a
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    professor of medicine at the university
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    of colorado i see patients
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    but i've also been doing research for
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    almost 40 years
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    trying to figure out the cause of
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    obesity and diabetes
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    today i'm going to present to you a very
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    exciting story
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    uh about a biologic switch that i
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    believe is the underlying mechanism
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    driving obesity today
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    and this talk i'm going to talk about
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    the discovery of the switch
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    in the next talk i'll talk about foods
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    that activate the switch
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    and on the third talk i will talk about
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    how it affects diseases beyond obesity
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    and diabetes including conditions like
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    cancer and dementia
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    the the talks are basically based on uh
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    related to my book
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    called nature wants us to be fat right
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    here
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    uh and um i i'm looking forward to to
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    starting and telling you about this
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    story
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    so the first thing just to give a
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    disclosure
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    i do
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    have a small company that i have
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    started to try to make inhibitors to
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    block this pathway it is not with the
  • 00:01:28
    purpose to make money it's the purpose
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    to take my science and the science we
  • 00:01:32
    discovered to the clinic because i
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    believe it can actually hopefully help
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    save millions of people in the long run
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    i also should say that although the
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    research is very strong and published in
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    the top journals uh it is not
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    universally agreed to others
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    and uh you know we'll have to
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    see how science uh you know
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    validates or not uh the work that uh
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    that i present but it's a very strong
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    data and i think that uh it's very well
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    worthy of uh presenting to you
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    so uh we call this nature wants us to be
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    fat part one
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    so the very first thing to be aware of
  • 00:02:14
    is that you know everyone knows we're in
  • 00:02:16
    an epidemic of obesity and diabetes uh
  • 00:02:19
    but you know
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    it really began around 1900
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    and about that time about 1 in 30 people
  • 00:02:26
    were overweight or obese
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    and approximately
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    1 in 50 000 were diabetic today it's
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    like 12 percent are diabetic like 30 are
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    obese
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    hypertension now affects 30 percent of
  • 00:02:41
    our population
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    uh chronic kidneys is very common
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    uh heart disease is the number one cause
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    of death i mean it was rare back in 1900
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    for coronary artery disease
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    so we've seen a dramatic increase in
  • 00:02:57
    these diseases and while we've developed
  • 00:03:00
    great ways to manage and treat these
  • 00:03:02
    diseases and you know and
  • 00:03:05
    surgeries and stents and thrombolytic
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    therapies and all these different types
  • 00:03:10
    of treatment it would be a lot better if
  • 00:03:12
    we could figure out the cause so that we
  • 00:03:15
    could actually prevent these diseases
  • 00:03:17
    from happening
  • 00:03:20
    well one of the things we do know is
  • 00:03:22
    that people with obesity
  • 00:03:24
    often have a constellation of findings
  • 00:03:26
    they don't just have
  • 00:03:28
    being overweight they'll be pre-diabetic
  • 00:03:31
    where their blood glucose will be
  • 00:03:33
    slightly elevated they'll have mildly
  • 00:03:35
    elevated blood pressure they'll have
  • 00:03:38
    increased fats not just in their tissues
  • 00:03:40
    what we call adipose tissue but also in
  • 00:03:43
    their blood and their liver and other
  • 00:03:45
    sites
  • 00:03:46
    they'll
  • 00:03:47
    have
  • 00:03:50
    some evidence of systemic inflammation
  • 00:03:52
    and another particularly interesting
  • 00:03:54
    finding is that many of them will have a
  • 00:03:56
    high
  • 00:03:57
    uric acid in their blood and uric acid
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    is present in everybody it's kind of a
  • 00:04:02
    breakdown product from
  • 00:04:04
    uh you know nucleic acids and dna
  • 00:04:07
    and we we make this stuff and then we
  • 00:04:09
    excrete it but it seems to be high in
  • 00:04:13
    patients with obesity and metabolic
  • 00:04:15
    syndrome and it can cause a disease
  • 00:04:17
    called gout where you get this arthritis
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    that affects typically the big toe
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    anyway so obesity metabolic syndrome is
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    the
  • 00:04:28
    name for this constellation of science
  • 00:04:30
    and the bad part is that if you're
  • 00:04:32
    pre-diabetic it increases your risk
  • 00:04:34
    become diabetic if you have elevated
  • 00:04:36
    blood pressure it increases your risk to
  • 00:04:37
    become hypertensive if you're overweight
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    it increases your risk to become obese
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    you know etc etc you have mild kidney
  • 00:04:45
    disease with
  • 00:04:46
    early on and then you can develop kidney
  • 00:04:48
    disease as you get older and all these
  • 00:04:50
    add up to increase risk for stroke and
  • 00:04:53
    heart disease and so forth so it's one
  • 00:04:56
    kind of related problem some people
  • 00:04:59
    present more with the fatty liver others
  • 00:05:01
    present more with the diabetes but it's
  • 00:05:04
    all part of one syndrome
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    so that means that there could be
  • 00:05:08
    a central mechanism driving it all
  • 00:05:12
    now
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    a lot of people think that what's
  • 00:05:14
    driving it all is is being overweight
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    and obese and that it's really simple
  • 00:05:19
    that it's we're eating the wrong foods
  • 00:05:21
    we're we're watching too much tv and
  • 00:05:24
    activity leads to weight gain
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    you know and so that you know one of the
  • 00:05:29
    most classic hypotheses was was
  • 00:05:33
    uh presented by uh elliott joslin way
  • 00:05:36
    back in the 1930s and he said you know
  • 00:05:39
    it's sort of obvious people are eating
  • 00:05:41
    too much they're exercising too little
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    this we learned about in physics it's
  • 00:05:46
    called the law of thermodynamics too
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    much in too little out and you have to
  • 00:05:50
    store the extra as fat
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    and so if we're eating too many calories
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    and we're exercising too little that's
  • 00:05:57
    it and you know what you should do
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    exercise you know what you should do
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    reduce your food intake it should be
  • 00:06:03
    easy
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    but it isn't easy and you and i both
  • 00:06:06
    know it
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    you can't yes you can lose weight by you
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    know exercising and eating less but
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    there's something that seems to drive us
  • 00:06:14
    to become obese again when we were young
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    and
  • 00:06:17
    uh 18
  • 00:06:19
    and 20 years old you know it seemed like
  • 00:06:21
    for many of us that we were invincible
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    we could eat anything we want we could
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    do anything we wanted to do didn't
  • 00:06:27
    matter we weren't going to gain weight
  • 00:06:28
    but something changed we call it our
  • 00:06:31
    metabolism has changed you know where
  • 00:06:33
    now as we get older suddenly it's easier
  • 00:06:35
    to gain weight but why is that what's
  • 00:06:38
    driving it what's activating this
  • 00:06:40
    biologic process
  • 00:06:42
    that causes waking
  • 00:06:45
    so we were very interested in this and
  • 00:06:48
    uh we approached it multiple ways i i
  • 00:06:51
    wanted to not just do classic research
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    but i wanted i reviewed history and
  • 00:06:55
    archaeology and i wanted to think
  • 00:06:57
    outside the box
  • 00:06:58
    and i began to realize that maybe one
  • 00:07:00
    way to think about this is not to think
  • 00:07:02
    about obesity as a disease or as a
  • 00:07:04
    condition that's bad
  • 00:07:06
    because some animals in the wild
  • 00:07:08
    actually intentionally become obese
  • 00:07:11
    it's like something good and if we could
  • 00:07:13
    understand what it was how it was being
  • 00:07:17
    good and what was driving it and how
  • 00:07:19
    they were how animals turn it on to
  • 00:07:21
    become obese then it could be a solution
  • 00:07:24
    it could be an answer
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    for why we're becoming
  • 00:07:28
    obese so the first thing to know is that
  • 00:07:31
    animals actually regulate their weight
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    really well they eat too much one day
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    low eat less the next they keep their
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    weight stable if you over
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    feed them or if you fast them your
  • 00:07:42
    weights will change but then when you
  • 00:07:43
    stop that they'll go right back to the
  • 00:07:45
    weight and not just their normal weight
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    their normal weight for that time of the
  • 00:07:50
    year it's very really interesting so
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    weight is normally tightly regulated
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    normally
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    but there are some animals that will
  • 00:08:00
    intentionally gain weight and so they'll
  • 00:08:02
    maintain their normal weight nine months
  • 00:08:04
    a year and then you know a few months
  • 00:08:06
    before winter
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    suddenly they start preparing for for
  • 00:08:11
    winter and they start eating a lot like
  • 00:08:13
    the bear the hibernating ground squirrel
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    suddenly they they go from being tightly
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    regulated to one where they're
  • 00:08:20
    dramatically eating more gaining fat and
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    so forth and and the same thing's true
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    for birds that have to fly long
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    distances or birds that have to nest for
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    several months they'll put on all this
  • 00:08:32
    weight and the weight the fat actually
  • 00:08:35
    provides a caloric source
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    it's like a type of calorie they can use
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    when there's no food around
  • 00:08:42
    because when they break down the fat
  • 00:08:44
    it's basically a type of stored energy
  • 00:08:46
    and they will release energy that they
  • 00:08:48
    can use and everything's about energy
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    well it's not just the calories and the
  • 00:08:54
    energy that's produced uh when you burn
  • 00:08:57
    fat you also produce water and for some
  • 00:09:00
    animals in the world that you know
  • 00:09:01
    they're really water is kind of a
  • 00:09:03
    critical thing and so if you like living
  • 00:09:05
    in the desert it's it's good to have a
  • 00:09:07
    little extra fat on board because when
  • 00:09:09
    you burn the fat you produce water
  • 00:09:11
    that's why the camel has a hump on its
  • 00:09:13
    back that's why some of these
  • 00:09:15
    fat
  • 00:09:16
    tailed animals
  • 00:09:18
    you know like the fat tail lemur
  • 00:09:21
    when it when it hibernates they call it
  • 00:09:23
    estivation in the summer but when they
  • 00:09:25
    hibernate they're burning the fat in
  • 00:09:27
    their tail to provide water to get
  • 00:09:29
    through the dry season and whales they
  • 00:09:32
    they don't drink seawater that's too
  • 00:09:34
    salty for them so they get their water
  • 00:09:36
    from food and some of it from the fat
  • 00:09:38
    they have and they are fat
  • 00:09:41
    all right
  • 00:09:42
    so
  • 00:09:43
    uh so in the wild
  • 00:09:45
    fat is a good thing it fat can keep you
  • 00:09:47
    alive fat can is a mechanism to help you
  • 00:09:50
    survive when there's no food and no
  • 00:09:52
    water
  • 00:09:54
    but it isn't
  • 00:09:55
    when these animals become fat it isn't
  • 00:09:57
    just they become fat
  • 00:09:59
    they actually develop all those features
  • 00:10:01
    of metabolic syndrome that we were
  • 00:10:03
    talking about
  • 00:10:04
    that we get
  • 00:10:05
    they become insulin resistant they raise
  • 00:10:07
    their blood pressure
  • 00:10:09
    they increase the fat in their liver
  • 00:10:11
    they increase the fat in their blood
  • 00:10:14
    they they do all these different things
  • 00:10:16
    that we that we see in people with
  • 00:10:18
    metabolic syndrome it's like uh an
  • 00:10:21
    orchestra
  • 00:10:22
    it's like uh it's like uh
  • 00:10:25
    you know there's it isn't just about one
  • 00:10:26
    guy i'm gonna increase the fat in you
  • 00:10:29
    it's you know the guy's saying i'm going
  • 00:10:31
    to make you insulin resistant i'm going
  • 00:10:33
    to raise your blood pressure i'm going
  • 00:10:34
    to give you some systemic inflammation
  • 00:10:37
    it's a survival response it's an
  • 00:10:39
    orchestrated response which suggests
  • 00:10:42
    that there may be one driving cause
  • 00:10:45
    now you may say well how is insulin
  • 00:10:48
    resistance part of a survival response
  • 00:10:50
    but the way it is
  • 00:10:52
    is that normally
  • 00:10:54
    a lot of our tissues like glucose
  • 00:10:56
    glucose is the main carbohydrate in our
  • 00:10:59
    blood that we use
  • 00:11:01
    as a fuel so yeah we use fat as a fuel
  • 00:11:04
    but in terms of carbohydrates we use
  • 00:11:06
    glucose as our primary go-to fuel and
  • 00:11:09
    it's used a lot by the brain it's used
  • 00:11:11
    in tissues like the muscle but
  • 00:11:13
    interestingly it requires a hormone of
  • 00:11:16
    insulin to move the glucose from the
  • 00:11:19
    blood into the muscle
  • 00:11:21
    but there's less need for insulin in the
  • 00:11:23
    brain the brain you know a lot of the
  • 00:11:25
    brain can use glucose without insulin so
  • 00:11:28
    when you become insulin resistant
  • 00:11:30
    there's less glucose going to the muscle
  • 00:11:32
    so there's more glucose that can go to
  • 00:11:34
    the brain basically it allows the
  • 00:11:37
    glucose to build up in the blood
  • 00:11:39
    so there's more for the brain and and
  • 00:11:41
    that is a good thing if you're if
  • 00:11:42
    there's a food shortage you want to
  • 00:11:44
    preserve the glucose you have
  • 00:11:47
    for the organs that count and when it
  • 00:11:50
    comes to survival the brain is the key
  • 00:11:52
    okay it isn't the heart of the muscle
  • 00:11:54
    the kidneys i'm a kidney doc but it's
  • 00:11:57
    not none of those it's the brain you've
  • 00:11:58
    got to be able to think if you're going
  • 00:12:00
    to survive
  • 00:12:01
    so what triggers this survival response
  • 00:12:04
    well for sure we we've already known
  • 00:12:06
    this for for some time that many animals
  • 00:12:09
    will use fruit as a mechanism to to
  • 00:12:12
    start increasing their fat
  • 00:12:15
    and this was this is known that the bear
  • 00:12:17
    for example can eat ten thousand grapes
  • 00:12:19
    in a day in the fall and it goes from
  • 00:12:21
    kind of tightly regulating its way to
  • 00:12:23
    gaining eight to ten pounds a day
  • 00:12:26
    you know birds will switch from insects
  • 00:12:28
    more towards fruit in the fall they use
  • 00:12:30
    the fruit to increase their fat there's
  • 00:12:32
    even fish that eat fruit fallen from
  • 00:12:36
    trees into the river like on the amazon
  • 00:12:38
    when it floods and they use that fruit
  • 00:12:40
    to build up their fat stores so that
  • 00:12:43
    they can make it through when the river
  • 00:12:44
    contracts and there's less food around
  • 00:12:47
    and there's primates like the
  • 00:12:49
    the orangutan loves fruit and will sit
  • 00:12:51
    in a fruit in a tree and eat fruit all
  • 00:12:55
    day long and so it's eating huge amounts
  • 00:12:57
    of fruit getting a lot of this so what
  • 00:12:59
    are they getting well you have to know
  • 00:13:01
    that the main nutrient in fruit is
  • 00:13:04
    fructose
  • 00:13:05
    and that's a sugar it's sort of like
  • 00:13:06
    glucose it's distinct from glucose it's
  • 00:13:09
    much sweeter in fact if you take glucose
  • 00:13:12
    and you give it to a person it's just
  • 00:13:13
    very lightly sweet
  • 00:13:15
    they people tend to like it but they
  • 00:13:17
    don't love it and so what they what
  • 00:13:20
    we've discovered is that when fructose
  • 00:13:22
    and glucose are together
  • 00:13:23
    then suddenly you have something that
  • 00:13:25
    people love and that was the discovery
  • 00:13:28
    of sugar
  • 00:13:29
    table sugar sucrose which is a fructose
  • 00:13:32
    and glucose molecule bound together and
  • 00:13:34
    then in the 70s they discovered that
  • 00:13:37
    they could make a sweetener from corn
  • 00:13:39
    called high fructose corn syrup which is
  • 00:13:41
    a mixture of fructose and glucose
  • 00:13:43
    and then of course there's what we call
  • 00:13:46
    hey those high carb foods like potatoes
  • 00:13:48
    and rice and and they they don't they
  • 00:13:51
    have starch they don't have sugar so
  • 00:13:53
    they don't have fructose in them but uh
  • 00:13:55
    what happens is these foods have a lot
  • 00:13:58
    of starch and they break down to glucose
  • 00:14:00
    and as we'll learn in lecture two
  • 00:14:02
    unfortunately these foods can
  • 00:14:05
    can also have a role in causing obesity
  • 00:14:08
    and it's gonna be through the same
  • 00:14:10
    pathway but we're gonna hold off on that
  • 00:14:12
    for now and just move on with now that
  • 00:14:16
    we know that the fruits that these
  • 00:14:17
    animals eat contains fructose so the
  • 00:14:20
    question was could fructose be
  • 00:14:23
    a nutrient that activates the switch
  • 00:14:25
    that makes you want to gain fat could
  • 00:14:26
    that be the driver of the biologic
  • 00:14:29
    switch so we took mice lab mice we put
  • 00:14:32
    fructose in the drinking water and by
  • 00:14:34
    god they loved the drinking water they
  • 00:14:36
    were drinking a lot for the first couple
  • 00:14:38
    weeks they held their weight stable
  • 00:14:40
    because they were still regulating their
  • 00:14:42
    weight and then something changed
  • 00:14:45
    and they suddenly lost their control of
  • 00:14:48
    appetite and they start eating more and
  • 00:14:49
    more they exercise less and less they
  • 00:14:52
    become less active especially when
  • 00:14:53
    they're not
  • 00:14:55
    you know what we call resting activity
  • 00:14:57
    metabolism dropped and what happened was
  • 00:15:00
    they became fat
  • 00:15:01
    so the
  • 00:15:03
    the equation was the same they're eating
  • 00:15:04
    too much they're exercising too little
  • 00:15:06
    but it's being driven
  • 00:15:08
    not by
  • 00:15:09
    a desire
  • 00:15:11
    it's i mean it's not being driven by
  • 00:15:14
    behaviors it's actually a special food
  • 00:15:16
    you give them this food and suddenly
  • 00:15:18
    they start eating more
  • 00:15:22
    so what is it about the food is it the
  • 00:15:24
    taste for example or is it the
  • 00:15:26
    metabolism you know what is it that
  • 00:15:28
    makes fructose cause this syndrome
  • 00:15:32
    and so what we did was we took mice that
  • 00:15:35
    couldn't taste let's just see if it's
  • 00:15:37
    taste
  • 00:15:38
    and so we took mice that were that had
  • 00:15:40
    lost their taste because of a genetic
  • 00:15:42
    manipulation and then we offer them
  • 00:15:45
    fructose or water and you know normally
  • 00:15:48
    uh if you if they have two bottles to
  • 00:15:50
    choose from and they're they both
  • 00:15:52
    contain water
  • 00:15:53
    they'll take the water evenly they'll
  • 00:15:55
    take about half of it from this bottle
  • 00:15:57
    half from that bottle and you can switch
  • 00:16:00
    the bottles and you know nothing happens
  • 00:16:01
    but if you give them sugar water or
  • 00:16:04
    fructose water and drinking water
  • 00:16:07
    normally animals will take about eighty
  • 00:16:09
    percent of their of their fluid from the
  • 00:16:11
    sugar
  • 00:16:12
    and twenty percent from the drinking
  • 00:16:14
    water so they'll drink some sugar water
  • 00:16:16
    and but they'll drink about four times
  • 00:16:18
    more
  • 00:16:19
    and you know if they can't taste you
  • 00:16:21
    would think that they wouldn't care
  • 00:16:23
    but guess what
  • 00:16:25
    a master can't taste can still figure
  • 00:16:27
    out where the sugar is and it will take
  • 00:16:30
    the sugar water just like it will
  • 00:16:32
    uh a normal mouse except that
  • 00:16:35
    overall it takes less sugar
  • 00:16:37
    but the preference is the same it's it
  • 00:16:40
    still takes about four times
  • 00:16:42
    for every for if you if they have their
  • 00:16:45
    choice they're going to go to the sugar
  • 00:16:46
    water four times more even if the total
  • 00:16:49
    amount of sugar they eat will be less so
  • 00:16:50
    the taste is there to encourage you to
  • 00:16:53
    to find the foods that are sweet
  • 00:16:56
    and it they probably encourage a little
  • 00:16:58
    bit more intake but it's actually uh
  • 00:17:01
    doesn't affect your desire for it so the
  • 00:17:04
    desire
  • 00:17:05
    for sugar water
  • 00:17:07
    is independent of taste
  • 00:17:09
    and they will still get fat
  • 00:17:12
    if you give them sugar water
  • 00:17:14
    they still get fat even though they
  • 00:17:15
    can't taste it
  • 00:17:17
    amazing
  • 00:17:20
    now
  • 00:17:20
    if you block their ability to metabolize
  • 00:17:23
    fructose and we can do that by blocking
  • 00:17:25
    the enzyme i call that enzyme khk and
  • 00:17:29
    when you block it we call it a knockout
  • 00:17:31
    so uh so these these mice can't
  • 00:17:34
    metabolize fructose well when you can't
  • 00:17:35
    metabolize fructose guess what they
  • 00:17:38
    don't care for for the for fructose
  • 00:17:40
    anymore and they don't get obese even
  • 00:17:42
    when you force them to eat the same
  • 00:17:44
    amount
  • 00:17:45
    so there's something about fructose
  • 00:17:48
    that's making them
  • 00:17:50
    want to
  • 00:17:51
    they crave it even though they can't
  • 00:17:53
    taste it
  • 00:17:54
    and they will get fat from it even if
  • 00:17:57
    they can't taste it and it's something
  • 00:17:58
    to do with the metabolism of fructose so
  • 00:18:01
    let's figure out how that works
  • 00:18:04
    why how does fructose work
  • 00:18:06
    well
  • 00:18:07
    you know and and is it from is it all
  • 00:18:10
    from calories because i'm sure you guys
  • 00:18:12
    have heard hey you know
  • 00:18:15
    it isn't just calories i mean if it were
  • 00:18:16
    just calories then why would a low-carb
  • 00:18:18
    diet be so much better than a low-fat
  • 00:18:21
    diet and we know that low-carb diets
  • 00:18:23
    really are better right that's why
  • 00:18:25
    you're watching this show
  • 00:18:28
    because low-carb diets do work so the
  • 00:18:30
    question is what what is it
  • 00:18:32
    is it more it's got to be more than
  • 00:18:34
    calories well it is more than calories
  • 00:18:36
    but let's let's do this scientifically
  • 00:18:38
    let's try to figure it out so one way to
  • 00:18:40
    figure it out is you take animals
  • 00:18:43
    and you feed them the exact same number
  • 00:18:44
    of calories you can get sugar and you
  • 00:18:47
    can get fat or you can you know fat in
  • 00:18:50
    your diet or you can get um fructose and
  • 00:18:53
    you and we're going to not give you
  • 00:18:54
    fructose so we take this big
  • 00:18:57
    all these rats and we say you guys are
  • 00:19:00
    all going to eat the same amount but of
  • 00:19:01
    course we can't really tell them
  • 00:19:03
    you know you're going to eat only x
  • 00:19:05
    amount so we have to serve them the same
  • 00:19:08
    amount of food but it what happens is to
  • 00:19:11
    do this right
  • 00:19:12
    after you if you serve them all the same
  • 00:19:14
    amount of food there's always one guy
  • 00:19:15
    that eats less than the others right
  • 00:19:17
    so if you really want to do it right you
  • 00:19:19
    have to feed them all the same amount as
  • 00:19:21
    the guy that gets the least so basically
  • 00:19:24
    all the animals end up eating the same
  • 00:19:26
    amount as the guy who eats the least now
  • 00:19:28
    when we did this experiment we did this
  • 00:19:29
    multiple times but one time we did the
  • 00:19:31
    experiment where one one of the poor
  • 00:19:33
    guys had cancer so he was eating much
  • 00:19:36
    less so that experiment's really
  • 00:19:38
    interesting because they're all eating
  • 00:19:39
    less than they normally eat so guess
  • 00:19:42
    what if you're going to put you on a
  • 00:19:44
    diet but one one group gets
  • 00:19:46
    high sugar or fructose and sugar
  • 00:19:49
    and the other group doesn't get a
  • 00:19:51
    fructose contains sugar what do you
  • 00:19:52
    think happens
  • 00:19:54
    well
  • 00:19:56
    when you when you can't eat all that
  • 00:19:57
    extra food even though you're hungry
  • 00:20:00
    you're not going to gain as much weight
  • 00:20:02
    because you're just not eating as much
  • 00:20:03
    food
  • 00:20:04
    but you'll still gain a little weight
  • 00:20:06
    because you're you're you're reducing
  • 00:20:08
    your your metabolism as well so when
  • 00:20:11
    when you activate this switch
  • 00:20:13
    you eat more but you uh have your
  • 00:20:15
    resting energy metabolism goes down and
  • 00:20:17
    so boom the animals got the sugar which
  • 00:20:20
    i here's
  • 00:20:22
    sucrose which is glucose and fructose
  • 00:20:24
    they actually gained a little weight
  • 00:20:25
    even though they're on the diet
  • 00:20:27
    so they were able to conserve their
  • 00:20:30
    energy
  • 00:20:31
    enough so that they actually gained
  • 00:20:32
    weight even though they were eating less
  • 00:20:34
    than they normally eat the control
  • 00:20:36
    animals of course lost weight
  • 00:20:39
    but it was just very small amounts so i
  • 00:20:41
    mean one could argue that it wasn't
  • 00:20:43
    really significant
  • 00:20:44
    but what was significant was even though
  • 00:20:47
    they're eat you know the differences in
  • 00:20:50
    weight are almost zero
  • 00:20:52
    or very minor
  • 00:20:54
    we're seeing huge differences in in
  • 00:20:56
    metabolism in the body so the animals
  • 00:20:59
    that got sugar got fatty liver they got
  • 00:21:01
    diabetic they developed hypertensive
  • 00:21:04
    i mean that you know it was a very
  • 00:21:05
    significant issues and so even when
  • 00:21:09
    calories are the same there's something
  • 00:21:11
    special about fructose it isn't
  • 00:21:14
    just making you eat more it is
  • 00:21:17
    poisoning your system where you're
  • 00:21:18
    developing diabetes and fatty liver and
  • 00:21:22
    all those things and you can do it even
  • 00:21:24
    when you're on a diet if you're eating a
  • 00:21:27
    high sugar
  • 00:21:28
    diet so what is it about
  • 00:21:31
    how does that work
  • 00:21:33
    how does what's the chemistry now this
  • 00:21:36
    forgive me we're going to go two or
  • 00:21:38
    three slides deep into chemistry but
  • 00:21:40
    it's it's not going to be super deep but
  • 00:21:42
    here it is when you eat fructose it's
  • 00:21:45
    like all nutrients you use it to make
  • 00:21:47
    energy you eat
  • 00:21:49
    calories to make energy
  • 00:21:52
    and we make energy that is either
  • 00:21:54
    immediate energy
  • 00:21:55
    which is the atp that makes me want to
  • 00:21:58
    be able to do everything you want or we
  • 00:22:00
    store it as energy which is what we call
  • 00:22:03
    as fat
  • 00:22:04
    and this is in
  • 00:22:05
    normal calories do this
  • 00:22:08
    but fructose is unique because what it
  • 00:22:10
    does is it has a side path
  • 00:22:14
    where it generates uric acid inside the
  • 00:22:17
    cell and i call it a non-caloric pathway
  • 00:22:20
    because it you can
  • 00:22:22
    you can activate that pathway even
  • 00:22:23
    without when you block the caloric
  • 00:22:26
    pathway
  • 00:22:27
    and yet when you do that
  • 00:22:29
    you activate the switch so the switch
  • 00:22:32
    turns out to be associated with this
  • 00:22:34
    non-caloric pathway unique to fructose
  • 00:22:38
    and what that does is it generates uric
  • 00:22:40
    acid inside the cell uric acid goes up
  • 00:22:44
    uh
  • 00:22:44
    in the blood
  • 00:22:46
    and it activates the switch and if you
  • 00:22:48
    lower uric acid in these animals and
  • 00:22:51
    that's all you do
  • 00:22:52
    you can actually affect the ability to
  • 00:22:55
    raise blood pressure to increase their
  • 00:22:57
    weight increase their triglycerides so
  • 00:22:59
    there's an association
  • 00:23:01
    there's an
  • 00:23:03
    a relationship where uric acid being
  • 00:23:05
    produced inside the cell is triggering
  • 00:23:09
    this switch and how does it do it well
  • 00:23:11
    here's the complicated slide
  • 00:23:14
    basically what it does is it helps reset
  • 00:23:17
    the energy in the cell to a lower energy
  • 00:23:20
    so with remember energy is atp
  • 00:23:24
    and then there's a stored energy which
  • 00:23:26
    is fat
  • 00:23:27
    so if if the way fructose works is it
  • 00:23:30
    makes the energy level or the atp level
  • 00:23:34
    low
  • 00:23:35
    because it tends to shunt more of the
  • 00:23:37
    calories to fat
  • 00:23:39
    so with when the atp levels go low it
  • 00:23:42
    sort of
  • 00:23:42
    activates an alarm it makes you want to
  • 00:23:44
    eat more forage for food and activate
  • 00:23:47
    the switch and the the actual way it
  • 00:23:50
    works is like a series of really cool
  • 00:23:52
    reactions so when fructose
  • 00:23:55
    initially
  • 00:23:56
    metabolizes it consumes
  • 00:23:59
    some of the atp and all foods consume
  • 00:24:02
    energy when they're being made but
  • 00:24:04
    fructose is unique because it consumes
  • 00:24:06
    it so rapidly that there's a fall
  • 00:24:08
    of energy in the cell normally energy
  • 00:24:11
    doesn't fall in the cell it's just
  • 00:24:13
    maintained at a very high level but
  • 00:24:15
    fructose triggers this drop in energy
  • 00:24:18
    that then
  • 00:24:19
    activates an enzyme that removes the amp
  • 00:24:22
    amp is what's used to reconstitute atp
  • 00:24:26
    so when you make amp then you can make
  • 00:24:28
    it back to atp but this guy's like the
  • 00:24:31
    giant sweeper and it sweeps away the amp
  • 00:24:34
    to make uric acid and then the uric acid
  • 00:24:36
    goes and stuns the energy factories
  • 00:24:38
    where atp is made reducing the atp
  • 00:24:42
    production by put blocking what we call
  • 00:24:45
    the krebs cycle and fatty acid oxidation
  • 00:24:47
    and all these things you don't really
  • 00:24:48
    want to hear about and then it blocks
  • 00:24:51
    the regeneration of atp in a low energy
  • 00:24:54
    state
  • 00:24:55
    by blocking this this great enzyme
  • 00:24:57
    called ap
  • 00:24:58
    amp kinase and the result is atp levels
  • 00:25:01
    fall
  • 00:25:02
    alarm signal
  • 00:25:04
    it makes the animal feel like it doesn't
  • 00:25:06
    have enough food because there's not the
  • 00:25:08
    energy is down but actually it does it's
  • 00:25:10
    just stored fat and the stored fat can't
  • 00:25:14
    be released into regular fat because
  • 00:25:16
    it's blocking that
  • 00:25:18
    so the fructose blocks the
  • 00:25:20
    ability of the fat to be
  • 00:25:22
    uh to be broken down to generate energy
  • 00:25:25
    so the animal feels that it's in a low
  • 00:25:28
    energy state it feels like it's starving
  • 00:25:30
    and guess what it wants to do eat it
  • 00:25:32
    wants to eat it wants to increase its
  • 00:25:34
    fat stores it's perfect it's a way to
  • 00:25:37
    increase fat in an animal that already
  • 00:25:38
    has fat because it tricks the system
  • 00:25:42
    into thinking that's that you're in a
  • 00:25:43
    low energy state and it puts you in a
  • 00:25:46
    low energy state
  • 00:25:48
    and what does that mean well again the
  • 00:25:50
    uric acid goes into these energy
  • 00:25:52
    factories called mitochondria and it
  • 00:25:55
    blocks the production of atp
  • 00:25:58
    and that leads to the stimulation and
  • 00:26:00
    of fat as a stored energy and and the
  • 00:26:03
    dropped atp leads to fatigue and being
  • 00:26:06
    tired and now you've got it you're
  • 00:26:09
    you're slower so you're spending less
  • 00:26:12
    energy
  • 00:26:13
    you're fatter you're putting weight on
  • 00:26:15
    you're hungry
  • 00:26:16
    it's making you fat and tired
  • 00:26:19
    not great but it's really good if you've
  • 00:26:21
    got to survive a period of time where
  • 00:26:23
    there's no food around
  • 00:26:26
    all right so so that's how the pathway
  • 00:26:29
    works but there's a there's another side
  • 00:26:31
    to it and the other side to it is that
  • 00:26:33
    we humans you and me
  • 00:26:36
    are much more sensitive to fructose than
  • 00:26:39
    most animals and that's because of
  • 00:26:41
    something that went wrong a long time
  • 00:26:43
    ago so this pathway was meant to save
  • 00:26:46
    our lives and guess what it did
  • 00:26:49
    but the consequences
  • 00:26:51
    of that is it made us more sensitive
  • 00:26:54
    to sugar and here's how it worked
  • 00:26:56
    so there's there's a famous scientist
  • 00:26:58
    named james neal
  • 00:27:00
    back in the 1950s he came up with this
  • 00:27:02
    idea when he was studying
  • 00:27:05
    natives in different environments
  • 00:27:07
    he said you know maybe the reason
  • 00:27:09
    obesity and diabetes are happening today
  • 00:27:12
    is because we
  • 00:27:14
    inherited or got mutations
  • 00:27:17
    that
  • 00:27:18
    affected our ability to survive in our
  • 00:27:20
    past when things were really bad so if
  • 00:27:22
    there was a famine
  • 00:27:24
    maybe we had a mutation that allowed us
  • 00:27:26
    to help survive the famine but it's
  • 00:27:28
    increasing our risk for obesity today
  • 00:27:30
    now that there's a lot of food and this
  • 00:27:32
    thing got called the thrifty gene
  • 00:27:34
    hypothesis it was really
  • 00:27:37
    this great idea that maybe we are more
  • 00:27:40
    the reason we're becoming obese and
  • 00:27:42
    diabetes are diabetic is because of
  • 00:27:44
    something that happened in our past
  • 00:27:46
    well i told you the importance of uric
  • 00:27:49
    acid and driving this whole process
  • 00:27:52
    and it's interesting humans have much
  • 00:27:54
    higher uric acids than almost all other
  • 00:27:57
    mammals so why
  • 00:27:58
    is it that we have these high uric acids
  • 00:28:01
    and guess what it was from a mutation a
  • 00:28:03
    mutation that occurred millions of years
  • 00:28:05
    ago that affected our ability to degrade
  • 00:28:08
    uric acid
  • 00:28:09
    so normally uric acid is like produced
  • 00:28:12
    when you eat foods you you can make uric
  • 00:28:14
    acid it's also produced when energy
  • 00:28:17
    turns around like atp
  • 00:28:19
    well like as we talked and we always
  • 00:28:21
    have some uric acid in our blood
  • 00:28:24
    normally there's an enzyme most animals
  • 00:28:26
    have an enzyme that degrades it we lost
  • 00:28:28
    that enzyme so when it we make it it's
  • 00:28:31
    harder to get
  • 00:28:32
    to to lower it because we can't break it
  • 00:28:35
    down so we have to excrete it through
  • 00:28:36
    our kidneys our gut and as a result we
  • 00:28:40
    can't do that as well as just breaking
  • 00:28:42
    it down and so we end up with higher
  • 00:28:44
    uric acid levels than most other animals
  • 00:28:47
    now why would we want that so
  • 00:28:49
    and and was it an advantage well when we
  • 00:28:52
    when when we look at the history of this
  • 00:28:55
    mutation we see that it actually
  • 00:28:56
    occurred millions of years ago that it
  • 00:28:59
    didn't just affect us it affected all
  • 00:29:01
    the apes the great apes the lesser apes
  • 00:29:03
    and humans so the this uh so it seemed
  • 00:29:06
    to have hit an ancestor and it happened
  • 00:29:10
    millions of years ago and the
  • 00:29:11
    consequence of a high uric acid that the
  • 00:29:13
    one that we best know is a disease
  • 00:29:16
    called gout because when our uric acid
  • 00:29:18
    gets really high it's pretty not very
  • 00:29:20
    soluble and it crystallizes and it loves
  • 00:29:23
    crystallizing joints causes this
  • 00:29:25
    terrible painful joint disease called
  • 00:29:28
    gout and it often hits the toe and these
  • 00:29:31
    crystals deposit in the and they
  • 00:29:34
    activate inflammation and it's hard to
  • 00:29:36
    walk and it hurts like for several weeks
  • 00:29:39
    until you finally get the pain under
  • 00:29:40
    control and the inflammation under
  • 00:29:42
    control and so why would we have a
  • 00:29:44
    mutation that increases our risk for
  • 00:29:47
    gout and what was happening to our
  • 00:29:49
    ancestors millions of years ago
  • 00:29:52
    so you had you know i i'm i love history
  • 00:29:55
    so i went back started looking at what
  • 00:29:57
    happened way back then and the first uh
  • 00:30:00
    the first apes uh appeared in africa
  • 00:30:02
    around 20 million years ago they were
  • 00:30:04
    larger animals than the other monkeys
  • 00:30:06
    and primates and these guys had big
  • 00:30:09
    heads they were tailless they live in
  • 00:30:10
    the trees and they ate mainly fruit they
  • 00:30:13
    loved
  • 00:30:15
    they loved fruit and so they were eating
  • 00:30:17
    a high fructose diet so they were eating
  • 00:30:20
    a lot of fructose and they were doing
  • 00:30:22
    pretty well they actually
  • 00:30:24
    were probably not eating
  • 00:30:26
    they had this mutation they had your
  • 00:30:28
    case way back then and so they were
  • 00:30:31
    doing very well and then what happened
  • 00:30:33
    was
  • 00:30:35
    we had a change in temperature
  • 00:30:38
    co2 levels fell and we had global
  • 00:30:41
    cooling
  • 00:30:42
    not global warming
  • 00:30:44
    and as the co2 levels fell in the
  • 00:30:47
    atmosphere
  • 00:30:48
    the
  • 00:30:49
    uh got cooler polar ice caps formed the
  • 00:30:52
    sea levels fell and africa which had
  • 00:30:55
    been pretty much uh separated from
  • 00:30:57
    europe suddenly as the sea levels fell
  • 00:31:00
    there were land bridges and the primates
  • 00:31:03
    and apes and other animals entered
  • 00:31:05
    europe
  • 00:31:07
    now initially when the when the fruit uh
  • 00:31:09
    when the uh
  • 00:31:11
    apes arrived to europe there were there
  • 00:31:13
    were plenty of fruit trees and they were
  • 00:31:15
    able to live just the same way they did
  • 00:31:17
    in africa but as it continued to cool
  • 00:31:21
    the trees became a little bit more
  • 00:31:23
    sparse and turned into woodlands instead
  • 00:31:25
    of rainforests and and they became more
  • 00:31:27
    deciduous and there became more uh open
  • 00:31:29
    areas and savannas and these
  • 00:31:33
    apes which were had been living in the
  • 00:31:34
    trees they had to come out of the trees
  • 00:31:36
    they had to forage more for food they
  • 00:31:38
    couldn't find fruit
  • 00:31:40
    all year long and especially during
  • 00:31:42
    their cooler months there was less fruit
  • 00:31:44
    available and so they started to starve
  • 00:31:47
    and you can see signs of starvation by
  • 00:31:49
    looking at the
  • 00:31:50
    uh their teeth and and
  • 00:31:53
    when when they're when an animal is
  • 00:31:54
    starving they can't put the enamel down
  • 00:31:56
    as well so they get these rings of of
  • 00:31:59
    poor growth of enamel and we and these
  • 00:32:02
    rings kind of look like tree rings and
  • 00:32:04
    they're a sign of seasonal starvation
  • 00:32:06
    these animals were starving
  • 00:32:08
    um especially during the cooler months
  • 00:32:10
    when there wasn't fruit available and
  • 00:32:13
    when that happened these poor guys
  • 00:32:16
    started to uh to to become extinct and
  • 00:32:19
    they they retreated to little colonies
  • 00:32:21
    and then around eight or ten million
  • 00:32:23
    years ago there were no more apes in
  • 00:32:25
    europe but in africa where it was wetter
  • 00:32:28
    and uh
  • 00:32:30
    was warmer uh the fruit trees were able
  • 00:32:32
    to were present all year round so there
  • 00:32:34
    wasn't really as as much of a survival
  • 00:32:38
    uh
  • 00:32:39
    problem there so the the the forest
  • 00:32:42
    contracted but the apes were able to
  • 00:32:44
    survive on their normal foods
  • 00:32:48
    but it's interesting the fossil record
  • 00:32:50
    suggests that our species and also the
  • 00:32:53
    great apes and the lesser eaves were all
  • 00:32:55
    seemed to be derided
  • 00:32:57
    by the fossil record from the apes in
  • 00:33:00
    europe not from the apes in africa in
  • 00:33:02
    fact there's this thought that some of
  • 00:33:04
    the european apes must have migrated
  • 00:33:07
    back to africa to be the ancestors of
  • 00:33:11
    humans and great apes and others may
  • 00:33:13
    have migrated to southeast asia to be
  • 00:33:16
    like the ancestor of the orangutan
  • 00:33:22
    and so i thought this was really
  • 00:33:24
    interesting and i flew to london to meet
  • 00:33:26
    with dr peter andrews a famous uh
  • 00:33:29
    anthropologist who studies these myocene
  • 00:33:32
    apes these apes from this period 10 to
  • 00:33:35
    you know 15 million years ago
  • 00:33:38
    and i told them our hypothesis that you
  • 00:33:41
    know that that this mutation had
  • 00:33:43
    occurred that affected uric acid that
  • 00:33:45
    uric acid is produced when you eat
  • 00:33:47
    fructose which is what these animals
  • 00:33:49
    were doing
  • 00:33:50
    and how this mutation could there could
  • 00:33:53
    potentially
  • 00:33:54
    uh
  • 00:33:55
    allow
  • 00:33:56
    an animal to generate more fat
  • 00:33:59
    from the same amount of fruit and that
  • 00:34:01
    that might allow it to store more fat in
  • 00:34:04
    a situation when there was less fruit
  • 00:34:06
    available that would allow them to
  • 00:34:08
    survive winter
  • 00:34:09
    and then uh and and from that be able to
  • 00:34:13
    to uh
  • 00:34:15
    survive
  • 00:34:18
    so uh he liked the idea we published the
  • 00:34:20
    hypothesis but of course we needed data
  • 00:34:23
    and one of the key experiments was done
  • 00:34:25
    by our collaborator gabby sanchez lozada
  • 00:34:28
    and what she did was she said okay
  • 00:34:30
    you know laboratory rats have uricase
  • 00:34:34
    and it's true you have to give them a
  • 00:34:36
    large amount of fructose to get them to
  • 00:34:38
    be fat what if i gave them a small
  • 00:34:41
    amount of fructose but inhibited their
  • 00:34:43
    uric ace could i still make them fat so
  • 00:34:46
    she put them on very small amounts of
  • 00:34:48
    soft drinks
  • 00:34:49
    and then she inhibited uricase on top of
  • 00:34:52
    it with or without and what she found
  • 00:34:54
    was that when she inhibited uricase the
  • 00:34:56
    uric acid levels were higher not
  • 00:34:58
    surprisingly but so was the prediabetes
  • 00:35:01
    the blood pressure the body weight the
  • 00:35:04
    the increase in triglycerides
  • 00:35:07
    the liver fat everything was enhanced it
  • 00:35:09
    was exactly true
  • 00:35:11
    we also even resurrected the extinct
  • 00:35:14
    gene we resurrected the extinct uri-case
  • 00:35:17
    gene
  • 00:35:18
    and found that when we did so that we
  • 00:35:20
    could
  • 00:35:22
    that it could block the ability for
  • 00:35:24
    fructose to make fat and that when we
  • 00:35:25
    mutated it like we did that we could
  • 00:35:28
    increase the fat response
  • 00:35:30
    there's even some data that uric acid
  • 00:35:32
    can be a survival factor
  • 00:35:35
    for starving animals and
  • 00:35:38
    way back in the 80s people found that if
  • 00:35:40
    they gave uric acid injections to
  • 00:35:43
    starving animals that it was similar to
  • 00:35:44
    giving glucose and that it could help
  • 00:35:46
    animals survive
  • 00:35:48
    especially if they had troubles breaking
  • 00:35:50
    down fat
  • 00:35:52
    so what we know
  • 00:35:54
    is that
  • 00:35:56
    this urecase mutation
  • 00:35:58
    uh was probably there to help uh help us
  • 00:36:01
    survive when there wasn't a lot of
  • 00:36:03
    fructose around and it enhanced our
  • 00:36:05
    ability
  • 00:36:06
    uh to make fat and to activate this for
  • 00:36:09
    uh the survival path we then included
  • 00:36:11
    foraging and blood pressure
  • 00:36:13
    and brain fuel these were all
  • 00:36:16
    uh things that uh that this mutation
  • 00:36:19
    allowed us to do so it was a good guy
  • 00:36:21
    but guess what
  • 00:36:23
    today it's not a good guy and the reason
  • 00:36:27
    is is is because of what's happened
  • 00:36:29
    since uh
  • 00:36:30
    that time 15 million years ago so when
  • 00:36:33
    that mutation occurred it only raised
  • 00:36:36
    the uric acid a little bit and the way
  • 00:36:38
    we know that is because if we go and we
  • 00:36:39
    study animals in the wild like the
  • 00:36:41
    orangutan or the chimpanzee that had the
  • 00:36:44
    mutation like us their uric acid levels
  • 00:36:47
    are only around two or three
  • 00:36:50
    and likewise i was able to
  • 00:36:52
    get blood samples from the yanomami
  • 00:36:54
    indians from actually the same
  • 00:36:57
    expedition that james neal went on and
  • 00:36:59
    we were able to show that the uric acid
  • 00:37:01
    levels in the yanomami indians was
  • 00:37:03
    around also around two or three so when
  • 00:37:06
    the mutation occurred the uric acid
  • 00:37:08
    levels up went up only a little bit to
  • 00:37:10
    like the two or three range and that was
  • 00:37:12
    enough to prevent us from starving
  • 00:37:16
    but not enough to make us fat
  • 00:37:18
    but then
  • 00:37:20
    a new source of fructose cane and that
  • 00:37:23
    new source
  • 00:37:24
    came from sugar and the discovery of
  • 00:37:26
    sugar cane in the ganges river valley
  • 00:37:29
    around 500 bc
  • 00:37:31
    led to suddenly a new sweetener that had
  • 00:37:34
    a lot of fructose and that people liked
  • 00:37:36
    and pretty soon diabetes and obesity
  • 00:37:39
    were being uh reported even from that
  • 00:37:41
    area and then the sugar got brought from
  • 00:37:43
    india into persia and china and egypt
  • 00:37:46
    and we start seeing reports of obesity
  • 00:37:48
    and diabetes there around 500 bc 500 a.d
  • 00:37:52
    for example and then it's brought in
  • 00:37:54
    through venice during the middle ages
  • 00:37:56
    and suddenly we start seeing obesity and
  • 00:37:58
    diabetes among the people who could
  • 00:38:00
    afford the sugar and it was very
  • 00:38:03
    expensive so it was really just the
  • 00:38:05
    royalty and the wealthy and in those
  • 00:38:07
    days um if you were poor you were not at
  • 00:38:10
    risk for obesity it was the wealthy who
  • 00:38:13
    were and it was the wealthy who could
  • 00:38:14
    afford sugar but then a sugar production
  • 00:38:17
    increased both you know with the sugar
  • 00:38:19
    plantations in the america
  • 00:38:21
    with the
  • 00:38:22
    uh advent of sugar beets
  • 00:38:24
    you know and then in the 1970s with the
  • 00:38:27
    with the production of high fructose
  • 00:38:29
    corn syrup from from corn suddenly these
  • 00:38:32
    sweeteners that have fructose in it are
  • 00:38:35
    because are everywhere and they're being
  • 00:38:37
    put in processed foods and they're being
  • 00:38:39
    put in and today about 15 of our diet
  • 00:38:43
    contains sugar and some people it's 25
  • 00:38:46
    of our diet is sugars and added sugars
  • 00:38:49
    that's a huge amount of sugars and 1700
  • 00:38:53
    we're only eating four percent or four
  • 00:38:55
    pounds of sugar
  • 00:38:57
    uh a year and today we're eating you
  • 00:38:59
    know 140 150 pounds of sugar a year
  • 00:39:03
    all right and
  • 00:39:05
    guess what now you got a lot of fructose
  • 00:39:07
    and we're sensitive to fructose obesity
  • 00:39:10
    and diabetes rates are soaring and they
  • 00:39:12
    parallel the rise in sugar uric acid
  • 00:39:15
    levels are soaring they're going up they
  • 00:39:17
    were around only three to four
  • 00:39:18
    milligrams
  • 00:39:20
    remember of you know following the
  • 00:39:22
    mutation but then with the advent of
  • 00:39:24
    sugar and foods and beer and other
  • 00:39:25
    things that can raise uric acid the uric
  • 00:39:28
    acid levels continue to increase in our
  • 00:39:30
    society and today about 20 million
  • 00:39:32
    people in the u.s have uric acid levels
  • 00:39:35
    of seven or higher and that's the level
  • 00:39:37
    where you start seeing gout and so it's
  • 00:39:40
    a real real problem
  • 00:39:42
    and when you have gout guess what you
  • 00:39:44
    see a lot of obesity you see a lot of
  • 00:39:47
    diabetes you see a lot of kidney disease
  • 00:39:49
    you see a lot of metabolic syndrome gout
  • 00:39:51
    is the greatest risk factor
  • 00:39:54
    for for all these these fee these
  • 00:39:56
    diseases they they're all part of one
  • 00:39:59
    syndrome
  • 00:40:00
    and now if you look at uric acid levels
  • 00:40:03
    and the frequency of obesity look
  • 00:40:05
    you have a uric acid of 10 you have a
  • 00:40:07
    huge chance of having obesity or
  • 00:40:09
    diabetes
  • 00:40:10
    it's it's amazing and you can see how it
  • 00:40:13
    isn't just the mutation it's the
  • 00:40:15
    mutation plus
  • 00:40:17
    a food that's driving the obesity
  • 00:40:19
    epidemic and it's true for kidney
  • 00:40:21
    disease and it's true for hypertension
  • 00:40:24
    and the higher the uric acid the greater
  • 00:40:26
    the risk and even in people who have a
  • 00:40:29
    high uric acid who have no other risk
  • 00:40:31
    factors no obesity no diabetes no
  • 00:40:33
    elevated triglycerides those people if
  • 00:40:36
    you have a high uric acid you're at
  • 00:40:38
    increased risk and this slide shows that
  • 00:40:40
    you have an increased risk for obesity
  • 00:40:41
    and hypertension and kidney disease and
  • 00:40:44
    diabetes and fatty liver it's bad news
  • 00:40:48
    it even predicts of course heart disease
  • 00:40:50
    because when it's predicting all these
  • 00:40:51
    different diseases it's going to also
  • 00:40:53
    predict and gout in particular is
  • 00:40:55
    associated with a higher risk for these
  • 00:40:57
    diseases
  • 00:40:59
    well what about fruit i mean
  • 00:41:02
    you know i understand that fructose is
  • 00:41:04
    is causing the obesity epidemic but
  • 00:41:06
    we've been told fruits are good
  • 00:41:08
    is fruit of comfort well the vast
  • 00:41:11
    majority of fructose you're getting is
  • 00:41:12
    from sugar it's from added sugars fruit
  • 00:41:15
    makes up just a small amount and most
  • 00:41:17
    fruits when we eat them we're only
  • 00:41:19
    eating a small amount that and the fruit
  • 00:41:21
    has
  • 00:41:22
    only a limited amount of fructose when
  • 00:41:24
    we're eating an individual fruit if
  • 00:41:26
    you're a bear and you're eating 10 000
  • 00:41:28
    berries you're gonna get fat okay if you
  • 00:41:31
    had a bowl of grapes on the couch you're
  • 00:41:33
    going to get fat that
  • 00:41:35
    it adds up but if an individual fruit is
  • 00:41:38
    not going to do it it's got fiber it's
  • 00:41:39
    got vitamin c it's got potassium it's
  • 00:41:41
    got a lot of things that block the
  • 00:41:43
    effects of fructose
  • 00:41:45
    and so you have to eat a fair amount
  • 00:41:47
    especially ripe
  • 00:41:48
    fruit and we tend to like tart fruit and
  • 00:41:51
    what's more the intestine
  • 00:41:53
    removes about the first four or five
  • 00:41:55
    grams of fructose so that really helps
  • 00:41:58
    out a lot too
  • 00:41:59
    so natural fruits are good so in summary
  • 00:42:02
    there is a biologic switch obesity is
  • 00:42:05
    driven by a switch
  • 00:42:07
    that switch
  • 00:42:08
    is fructose and what the how the
  • 00:42:10
    fructose works is it drops the energy in
  • 00:42:13
    the cell
  • 00:42:14
    creating a false sense of starvation
  • 00:42:17
    and the major sources of fructose are
  • 00:42:19
    sugar and high fructose corn syrup they
  • 00:42:21
    make up the most and it's really liquid
  • 00:42:24
    sugar that's the worst
  • 00:42:26
    humans are more sensitive to fructose
  • 00:42:28
    because they had a mutation in your case
  • 00:42:31
    15 million years ago so we are more
  • 00:42:33
    sensitive to sugar and we're eating a
  • 00:42:35
    lot of it some people make it 25 of
  • 00:42:38
    their diet and this is why we're
  • 00:42:40
    developing obesity diabetes metabolic
  • 00:42:42
    syndrome and all these diseases
  • 00:42:44
    now i'm going to tell you a very bad
  • 00:42:46
    surprise in the next lecture about how
  • 00:42:48
    the body
  • 00:42:49
    can also make fructose and how certain
  • 00:42:52
    foods that don't contain sugar can still
  • 00:42:54
    cause obesity so stay tuned thank you
  • 00:42:57
    very much
  • 00:42:58
    i want to do special thanks to my
  • 00:43:00
    collaborators and and of course all this
  • 00:43:03
    information is in my book nature wants
  • 00:43:05
    us to be fat thank you very much
  • 00:43:08
    [Music]
  • 00:43:18
    you
Tags
  • obesity
  • fructose
  • metabolism
  • uric acid
  • insulin resistance
  • sugar
  • historical diet
  • disease prevention
  • genetics
  • energy metabolism