How Dangerous Is Junk Food? with Dr. Robert Lustig

He is an emeritus professor from the University of San Francisco and he's written numerous books in this area , including Metabolical , which is his most recent one . I highly recommend it , but it's so great to have you on the program , Rob . Thanks for joining us .

Now , when I entered this field , the excitement was in sex differentiation why boys were boys and girls were girls , from the neck up , and also from a clinical standpoint , the excitement was in growth hormone , because growth hormone had just been approved by the FDA for treatment of growth hormone deficiency , and so that's what I thought I was going to do for my

career . I had minimal interest in the obesity , metabolism , diabetes , chronic disease field . In fact I went into pediatrics to stay out of chronic disease and of course now that's all I do . Funny how those things happen . Obesity was , of course , not an endocrine disease , except of course it was , you know , for all those years .

But in 1994 , we discovered this hormone called leptin , and leptin , which is a hormone that your fat cells make , which travels through the bloodstream to the brain to tell your brain that you have enough energy on board to burn properly to engage in normal , expensive metabolic processes , such as puberty and pregnancy , that basically regulate the rate of energy

expenditure .

So when that hormone was discovered , it became very clear that obesity was an endocrine disease , and it just so happens that when that happened , I was a physician working at St Jude Children's Research Hospital in Memphis , tennessee , the pediatric cancer hospital and so I had a cadre of about 40 children who had survived their brain tumors , and of course they had

multiple different endocrine problems because of the tumor or the surgery or the radiation . But one of the problems that was very glaring , very prevalent and very debilitating was that these kids were gaining weight hand over fist , nonstop , even though they weren't eating very much .

They were gaining weight at the rate of about a kilo a month , and so these kids were now 350 , 400 pounds , you know , when they were perfectly normal prior to their tumor , and the parents would complain to me . This is double jeopardy .

My child survived the tumor , only to succumb to a complication of the therapy , and so it was my charge , you know , to try to do something for them .

Well , because I'm a neuroendocrinologist , I knew about a literature in you know basic sciences where investigators had taken electrolytic lesions you know electrodes and put them into the hypothalamus of rats and buzzed , and these animals would then eat like there was no tomorrow and gain enormous amounts of weight , and we called this phenomenon hypothalamic obesity because

of the hypothalamic damage , and I rightly at that point assumed that these kids had the same problem as the rats . It's just that they got it because of their tumor , not because of an electrolytic lesion , and I also rightly assumed that the reason was because they couldn't see their leptin . So it was up to me to try to figure out what to do for them .

Well , I can't fix a brain and I couldn't stop , you know , the weight gain , you know , by trying to influence the brain . So I had to think well , what's downstream of that lesion ?

And we knew from the rat data that if you cut the vagus nerve , which is a nerve that goes from the brain to the pancreas , if you cut that vagus nerve , you can stop that weight gain .

So it appeared that the brain was thinking it was starving because of that damage and that the brain was telling the pancreas release more insulin in order to drive more energy into fat , in order to try to increase the leptin . But of course you would never see the leptin because the brain was broken .

So I thought , well , I can't , I'm not a surgeon , I can't cut a vagus nerve . But what I could do is give these kids a medicine that would suppress insulin release at the level of the pancreas .

And we had a drug that was available to us called octreotide , which was normally used to treat growth hormones secreting tumors of the pituitary , but it also suppressed insulin as well . And so we did an open label trial of eight kids , giving them this medicine to see whether or not it would have any effect .

And lo and behold , you know beyond my wildest dreams . You know of the eight patients that we treated in an open-label fashion . They all got better . Four of them lost a lot of weight . Four of them at least stabilized their weight . But something even more important happened these kids started exercising spontaneously .

These were kids who sat on the couch , ate Doritos and slept , and now they were physically active . One kid became a competitive swimmer . Two kids started lifting weights at home . One kid became the manager of his high school basketball team , running around collecting all the basketballs . I mean , these were kids who had checked out of life .

These were kids who the parents would say you know , my kid's gone , even though he's here , he's gone because he doesn't do anything , he's a lump on a log . And now they're saying I got my kid back . And the kid would say this is the first time my head hasn't been in the clouds since the tumor .

So this was really , really remarkable Because it suggested that the medicine changed their behavior .

So what we did was we did a double-blind placebo-controlled trial , using the medicine versus placebo , and this time we built a quality life questionnaire into the protocol and we found that when we got the insulin down with the medicine , these patients felt better and these patients started exercising .

And so what this showed me you know very clearly was the biochemistry comes first , that the behaviors that we associate with obesity , gluttony and sloth are actually secondary to the biochemistry rather than primary . And so everybody has been saying eat less , exercise more .

It turns out no , get the insulin down , and when you do , you will eat less and exercise more of your own volition . And so I turned my obesity program at UCSF into an insulin reduction program , get the insulin down , and we were enormously successful .

You know , and to this day you know , that's how our clinic practices and that's one of the reasons why you know we're going on 20 years now . So I'm very clear on why I do what I do , and it was the data that brung me . You know , I didn't have an invested interest or you know an agenda going in , you know . Basically I followed the data .

Everyone probably agrees we shouldn't eat junk food , but what is it about food that makes it junk or processed ? What are the key things to look out for Right ?

Insulin dynamics are defective . In virtually everyone who is obese , insulin is the driver of weight gain . Insulin shunts energy to fat . Insulin makes fat More insulin , more fat . Insulin makes fat , more insulin , more fat . Now these kids , they have high insulin because of their hypothalamic damage . Why does everyone else have high insulin ?

And that's where junk food comes in . So the question is what about junk food leads to high insulin ? And the answer is the liver is the downstream target of the pancreas . The pancreas releases insulin and it goes immediately to the liver via the portal vein .

And when the liver doesn't do its job , the pancreas knows that and releases more in an attempt to make the liver do its job . It's a negative feedback pathway .

So when your liver is sick , your pancreas overworks , okay , and that increase in insulin then floods the entire system , all over the body , and that's what drives the weight gain and it's also what drives the chronic disease . So you have to get the liver healthy .

You have to make the liver insulin sensitive so that the liver will respond to the insulin signal properly . So what is it about junk food that causes the liver not to work right ? And the answer is two things .

The first is the sugar , because it turns out that one molecule of sugar called fructose as you know , sugar , dietary sugar , sucrose , table sugar , cane sugar , beet sugar is two molecules , one's called glucose , one's called fructose . Glucose is the energy of life . Every cell on the planet burns glucose for energy .

Glucose is so goddamn important that if you don't consume it , your body makes it . You have to have glucose in your blood or you will die . Have to have glucose in your blood or you will die , but you don't have to consume it . You don't have to eat it Because it's so important . Your body can turn fat into glucose . It can turn protein into glucose .

It has multiple methods for being able to keep your glucose levels up . That's how important it is .

So people who don't consume glucose , people on a , say , ketogenic diet , or the Inuit or the Rendili or the Tokolau tribes , who basically consume only milk and meat and no carbohydrate , still have a serum glucose level because their livers will turn fat or protein into glucose . So you don't have to eat it , but you have to have it in your blood , fructose .

On the other hand , this other molecule , the sweet molecule , the molecule that makes candy and cakes and ice cream and breakfast cereal and everything else you know , sweet and addictive , okay , that molecule turns out to be completely unnecessary to all animal life on this planet .

There is absolutely no biochemical reaction in any animal cell , in any species on the planet , that requires fructose . It is completely irrelevant to all animals , especially humans . Now , we just so happen to like it a lot .

It just so happens that it is addictive because it stimulates the reward center in our brain , the same way cocaine , heroin , nicotine , alcohol do , but it is completely unnecessary . Well , it turns out that fructose , when it reaches the liver , causes your mitochondria , the little energy burning factories inside each of your cells , to become dysfunctional .

They don't work . And when they don't work , your liver can't burn the glucose . And what happens is it turns all of the carbohydrate into fat . This is a process called de novo lipogenesis , new fat making , turning carbohydrate , and especially sugar , into fat . And this is why everyone today now has fatty liver disease .

And when you have fat in your liver , your liver doesn't work right . And when your liver doesn't work right , your pancreas makes extra insulin . And when your pancreas makes extra insulin , guess what you got obesity and chronic disease . So ultra-processed food is bad because of too much sugar . But that's only one reason .

The second reason ultra-processed food is bad is because ultra-processed food has no fiber , and fiber , turns out , is essential . It's just not essential for you . It's essential for the bacteria in your intestine . So each of us has 10 trillion cells in our bodies , but we have 100 trillion bacteria in our intestines . Our intestinal bacteria outnumber us 10 to 1 .

Okay , well , they got to eat something . Well , what do they eat ? Well , they eat what you eat . The question is how much did you get versus how much did they get ? And what they like to eat is fiber . They will eat the fiber .

You can't digest the fiber because you don't have the enzymes in your intestine to do it , and the reason you don't is because the fiber is for them . So when you consume your food with fiber , you are feeding your microbiome , and when you feed your microbiome , your microbiome leaves you alone because they're happy .

When you don't feed your microbiome , your microbiome gets mad because they don't have anything to eat . So what do they do ? They eat the mucin layer right off your intestinal epithelial cells , which then expose your intestine to all of the junk in your intestine , which then causes systemic inflammation .

And since we are talking about inflammation in this podcast , this is one of the primary drivers of inflammation , and when you have inflammation , then that's another reason why your insulin doesn't work well . And so now you have another reason why your liver is dysfunctional because of what happened in your intestine , because you didn't feed your bacteria .

So ultra-processed food is bad because of the sugar , which causes mitochondrial dysfunction , and the lack of fiber , which causes systemic inflammation .

In fact , insulin resistance occurs with aging and arguably the majority of the US population has a degree of insulin resistance . They have elevated HA1Cs . They may not have crossed over into the pre-diabetic range , but with aging there's a general tendency towards increased insulin resistance and inflammation as a function of aging .

You know if you want to make it 88% , 93% , the point is , virtually everyone in America is suffering from this and the reason is because virtually everyone in America is eating the Western diet and it is the Western diet , the high sugar , low fiber diet that is driving this metabolic dysfunction .

Well , that fiber actually prevents the absorption of the fructose in the intestine . The soluble and insoluble fiber in the apple and this is true for virtually every real food , food that came out of the ground will have both soluble and insoluble fiber . They are not the same .

Soluble fibers , like pectins or inulin , you know , like what holds jelly together , and insoluble fibers , like cellulose , like the stringy stuff in celery . They're both fiber . Okay , they have different functions , they work together , they're synergistic , and so the apple has both .

And what will happen is the insoluble fiber , the cellulose , will act like a fishnet , a latticework on the inside of your intestine . The soluble fiber are globular .

They will plug the holes in the fishnet and together they will form an , a secondary barrier , a gel , a whitish gel that you can actually see on electron microscopy , and what that will do is it will serve as a secondary barrier preventing the absorption of glucose , fructose , sucrose , simple starches , from the gut into the bloodstream .

And so , yes , when you consume the apple , yes , you're consuming sugar , yes , you're consuming fructose , that's true , but that fructose is not for you , because it never gets absorbed by you . It rather goes further down the intestine where the microbiome will chew it up for its own purposes , because the fiber made it so .

So , when you eat the apple , it's not a problem . On the other hand , when you process that apple and turn it into apple juice and you have removed the fiber and now you can't set up that gel , now you will absorb it and now it does become a problem .

So , in fact , when you look at the meta-analyses , the statistical analyses of fruit versus diabetes , it turns out that the higher the fruit consumption , that the higher the fruit consumption , the more you are protected from diabetes , whereas the higher the fruit juice consumption , the more likely you are to get diabetes .

Because it's not the fruit , it's the fiber that matters .

One interesting speaker we've had who was Chris Palmer , who's written about now metabolic dysfunction and mental health and that's it's some very fascinating work . I'd like to look instead of all the way to mental illness . What do you think about the effects of metabolic dysregulation on sort of the normal person ?

You know there's that famous study with sugar drinks and violence and all and kids and it was just a correlative study . But what , what's ?

What do you think is going on with not people who are schizophrenic or or , you know , have clinical mental illness , but instead it's someone dealing with their boss at work or their spouse or their kids , or making political decisions and , you know , running the world government .

What is the effect of this junk food on normal people and the mental state of how people get along with each other ?

But what Dr Palmer espouses , and I believe as well , is that metabolic health and mental health are the same thing , and the reason is because of mitochondrial dysfunction in the brain . So you can have mitochondrial dysfunction in the liver , which I've already described . You can have mitochondrial dysfunction in the brain .

Now , it was always assumed that fructose doesn't get into the brain . Oh yes , it does . It absolutely does . It doesn't get into neurons , it gets into astrocytes , gets into the glial cells , gets into the cells that nourish the neurons instead . And what it does is it causes changes in neurotransmitter synthesis . So there are two neurotransmitters in the brain .

They do opposite things . One's called glutamate and the other one's called GABA , gamma-aminobutyric acid . Glutamate is excitatory , gaba is inhibitory . Turns out , glutamate becomes GABA . Glutamate is turned into GABA . There's two enzymes the glutamate is acted on by an enzyme called glutamine synthase , which turns the glutamate into glutamine .

And then there's a second one called glutamic acid decarboxylase , which turns the glutamine into GABA , turns out fructose , inhibits that glutamine synthase , and so what you end up with is an imbalance in neurotransmitters , between the excitatory and the inhibitory , which then have effects on cognition , effects on irritability and emotion , have effects on behavior , all sorts

of things that are documentable .

A colleague of mine , dr Bill Wilson , who is a very astute clinician in Lowell , massachusetts , has written a book called Brain Drain and in it he describes 22 symptoms that he put together from pattern recognition over 40 years , which he calls carbohydrate-associated reversible brain syndrome , carb syndrome , c-a-r-b syndrome how appropriate .

And things like brain fog , like forgetfulness , inability to access short-term memory , et cetera , things that people ascribe to you know bad day , lack of sleep , poor energy , blah , blah , blah . The bottom line is they're all fixable , they're all reversible . When you take the carbohydrate out of people's diets , they all get better .

So carbohydrate-associated reversible brain syndrome . Now , is it because of these changes in neurotransmitters ? Maybe Is it because of the mitochondrial dysfunction itself ? Maybe Is it because of changes in trophic factors in the brain , like , for instance , brain-derived neurotrophic factor or BDNF or leptin .

Maybe Is it because of changes in the microbiome which then send messages from the gut to the brain via the afferent vagus nerve . Maybe there are a lot of different ways that what go on in the body and what go on in the diet could ultimately affect cognitive , cognitive function and also emotional distress . And we haven't yet figured out what causes what .

But we do know that diet is really , really important . That we do know . And we do know that when you get the ultra-processed food out of your diet you feel a whole lot better , not just physically and metabolically , but in fact cognitively , behaviorally and above the neck . It has now been shown that ultra-processed food consumption correlates with dementia .

It has been shown that ultra-processed food correlates with addiction . It's been shown that ultra-processed food correlates with depression . So those are correlative diseases . We still need causation .

I agree , we're not there yet , but there's every reason to believe that mitochondria in your liver are very much like mitochondria in your brain in terms of how they work , and so we know how fructose affects mitochondria in the liver . It's very , very likely that it does similar problems , similar things in the brain .

I'm still very naive , but when I was naive about I thought that there was a lot of information , such as the information you're telling us now about how harmful these substances are in processed food , and I was under what I believe is a misconception that if I just educate the people , if we just get the message out there that so many people would benefit .

And I have friends who are professionals , healthcare professionals , highly educated people and they understand the damage that sugar causes , and one person just recently got diagnosed with a known heart disease on their CT scan and they've heard all the stories about sugar and they'll sit down to breakfast and have a glass of orange juice and a cereal .

It's not enough to educate people , is it ? Or what is the problem beyond just education here ? What else needs to be done ?

You can know cognitively that whatever it is you're addicted to it can be cocaine , heroin , nicotine , alcohol , sugar or gambling , social media , internet , gaming , shopping , pornography you can know that , whatever it is you're addicted to chemicals or behaviors .

They are ruining your life , your health , your community , your economy , your family and you are powerless to do anything about it . That's why they're addictive . That's the definition . So education alone is not enough .

And the reason is because when you over-release dopamine and that's what happens in the reward system dopamine is released and it gives you a feeling of reward . Okay , this feels good , I want more . Okay , but dopamine , just like glutamate , is an excitatory neurotransmitter . It excites the next neuron . Now , neurons like to be excited . That's why they have receptors .

But neurons like to be tickled , not bludgeoned , Whether it's glutamate or dopamine , you know , they like a quick burst and then they like it to go away and they like to recover from it . Okay , Chronic overstimulation of any neuron anywhere in the body doesn't matter where . Chronic overstimulation of any neuron will lead to neuronal cell death .

Now , neurons don't want to die . They have a plan B . They have a secondary defense mechanism . What they do is they downregulate the number of receptors so dopamine gets released , then the dopamine receptor goes down .

More dopamine gets released , more dopamine receptors go down , and so you end up needing a bigger and bigger hit to get a lower and lower response , until finally you need a huge hit to get nothing . And that phenomenon is called tolerance , and everyone who's ever experienced addiction knows about tolerance .

You need more and more to get less and less the law of diminishing returns . About tolerance you need more and more to get less and less the law of diminishing returns . But when those neurons actually do start to die , they don't come back , they're gone forever . Neurons don't divide , they are post-differentiation . So you lose a neuron , it's forever .

You lose a dopamine neuron , it's forever . And that means that even if you got over your addiction , you're not going to get those dopamine neurons back , which means that your ability to perceive reward and pleasure will forever be attenuated , because you'll never be able to get the same reward response . Well , that is why people go back and relapse .

That is why people they're trying to recapitulate that original high and they can't do it and sometimes they overdose and that's why so many you know former drug addicts , when they go back to using , end up , you know , in the morgue Because they , you know , tried to , you know , regenerate the same level of dopamine activity that they had previously and they can't

because those neurons are dead . So this phenomenon is very real . It goes on , you know , in a good 20 to 25% of the American adult population . And what people don't understand is that you know we have sugar addicts . Okay , If you say , oh , I have a horrible sweet tooth , you're a sugar addict until proven otherwise .

The problem is that because sugar's in everything , you can't even go cold turkey . So you constantly have that craving , you constantly have that need , you constantly have that draw and so you can't cut back . So this is a problem of the food industry , not just of individual patients .

Of course , we become the laboratory , you know , for the rest of the country , but the fact is , you know , this is a movement that people now do understand and are starting to get on board with , and the food industry is recognizing that they have a problem and what are they going to do about it is still open to question , but they have seen the data and I

can prove it . I can prove that the public is being educated Because in 2011 , the International Food Information Council , ific , which is a PR arm of the food industry , every year , they asked a question what foodstuff or what ingredient causes weight gain ? And back then , only 11% of the population said refined carbohydrate or sugar .

Virtually everyone said a calorie is a calorie , or I don't know a calorie , or I don't know . They asked the same question again seven years later , in 2018 . And now 33% of the public said refined carbohydrate and sugar , and it all came from the group that said a calorie is a calorie , or I don't know .

So we have the data to show that the public is being educated .

What I would do is I would get rid of all food subsidies , all food subsidies , all of them , not some of them , all of them . And the reason is because they distort the market .

And so when you subsidize corn , wheat , soy , sugar , which are the things that are currently being subsidized , what you're doing is , first of all , you're making everything else more expensive because you're providing the subsidy for these things , and all these things are the things that kill you .

And , number two , you're distorting the market to make it cheaper so that people will consume more of the things that kill you , consume more of the things that kill you . So if you got rid of the subsidies , okay , then you know the price of individual foodstuffs would you know , not be all you know would basically find their own rational market .

Even the libertarians , you know , can get on board with this . And it turns out that you know that people say well then the price of food would go up . Actually , not so .

The Giannini Foundation at UC Berkeley did this exercise several years ago and found that , in fact , the price of food would not change except for two items corn and sugar , which is exactly what we would want to go up in order to reduce total consumption . So for me , that's where it starts . That's what I would do Now . There are other things we can do .

For instance , at UCSF here in San Francisco in 2015 , we instituted for all of our campuses , throughout the entire Bay Area , what we call the Healthy Beverage Initiative . You cannot find a sugared soda anywhere at UCSF death . You cannot buy one . No vendor , no cafeteria , no , nothing .

Okay , if you want to drink a sugared soda , you have to bring it from home . I mean , we don't have police running around . You know spying on people , but you know so .

If you want , if you want to drink a sugared soda , then you bring it from home , but you can't buy it on campus , because we are a medical campus and we're trying to model for the public what you know rational consumption should be . You know where was smoking ? First banned Hospitals , for good reason , right . So what we did was we studied it .

When we put this into practice in 2015 , we studied it and it turned out that our employees improved their insulin sensitivity and reduced their waist circumference because we took it off campus so they could drink it when they went home , but what we found was that their total soda consumption was cut in half because they couldn't buy it at work .

There's an example of something you could do , and so , in fact , that process is now being implemented at all UCs across all of California . So that is going on right now . So there's an example of something we could do . So there are things that could be done .

In addition , we are working to try to establish an upper limit of added sugar in children's meals at school , because there's no reason for excess sugar being delivered to our children while they're , you know , under someone else's roof . So there are different things that could be done and we are doing them .

Thank you for asking .

Diet sweeteners alter the microbiome in different ways that ultimately lead to increased systemic inflammation and glucose intolerance . This has now been shown in several different studies , both in animals and in humans , and also turns out when sweet touches the tongue , you get an insulin response .

Anyway , the brain interprets sweet as sugar , whether it was sugar or not , and so you still get an insulin response . And if you get an insulin response , you're still going to gain weight . So it turns out that diet sweeteners are not the panacea , unfortunately .

They may have a role , because if you're a sugar addict , it may be a way to wean you off , like methadone for heroin addiction . There might be a value to it , but not as a substitute , as a tool , maybe as a substitute , no .

So , yes , unfortunately , what we really need to do is desweeten our lives , and the food industry obviously is fighting tooth and nail against that , because this is their juggernaut , this is their gravy train , this is what brung them . This is how they went from a one percent annual profit margin to a five percent annual profit margin .

This is how they get us to eat all their their junk uh , you know , is sugar's the hook . So we still have a lot of work to do .

We've had four cultural tectonic shifts in the last 30 years Bicycle , helmets and seatbelts , smoking in public places , drunk driving , condoms in bathrooms .

30 years ago , if a legislator stood up in a state house or Congress or Parliament or the Duma or anywhere else in the world and proposed any legislation around any four of those things , they'd have gotten left right out of town . Nanny , state liberty interest get out of my kitchen , get out of my bathroom , get out of my car .

Get out of my bathroom , get out of my car . Today they're all facts of life . No one's bellyaching about any of those . We have new things to bellyache about , like vaccines , right , but no one's bellyaching about those four . So how did we fix that ? How did that happen ? We taught the children . The children grew up and they voted and the naysayers are dead .

That's why this is a generational shift . But you have to start with education . You have to teach the public first and that is why I'm very happy to be here discussing this with you and hopefully some of your listeners will take some of these messages away and rethink their own thoughts on the problem .