The Obesity Code Lecture (Why do we get Fat?) Part 1

welcome to the lecture this is called the etiology of obesity and this is the first part of my six-part series looking at basically what the cause of obesity is and and then later on we'll get into how we can deal with that so let me start with a story this is William Banting he was a London Undertaker and he lived in the 1796 to 1878 and basically he had become very obese through the years starting in his mid 30s he had started to gain a few pounds every year until by age 62 he had weighed about 202 pounds which was really quite obese for that time and not being too happy with that whole situation he decided that he would do something about it so what he did was he went to see some physicians and they gave him some various advice such as increasing the exercise so living near the Thames he actually took up rowing and he decided that he would grow every day the problem was that he said that he developed a very healthy appetite but in the end he wasn't able to lose any weight so he went to see some other esteemed doctors at the time and he told him well all you need to do is decrease your caloric intake and you'll automatically lose weight but what he found was that he was just tired and hungry and he still wasn't able to lose weight so eventually he came to the attention of a French surgeon who told him about a specific diet which involved eating three meals a day of a meat fish or game with just very little stale toast or cooked fruit on the side and what happened was that he avoided very strenuously these fattening carbohydrates which were sugar and starch so the Brad beer sweet potatoes and what he found was that he actually was able to lose a significant amount of weight very quickly so he published this in a letter called letter on corpulence published in 1863 and it actually quickly became one of the best-selling diet books of its time and it's really considered one of the first diets this sort of idea of about obesity actually persisted for quite a few years so William Osler who is considered the father of modern medicine he authored the textbook the principles and practice of medicine which was very influential at the in it he discusses treatment of obesity and much of his ideas are similar to Banting and they featured lean beef veal mutton and eggs and that was his opinion he actually had published a monograph himself on obesity and its treatment and his thought was that what needed to be eaten was fatty foods they're crucial actually because they increased the tidy and therefore decrease fat accumulation his idea of course was very similar to Banting and that one needed to strenuously avoid the fattening carbohydrate up until the 1950s and 60s this idea was fairly prevalent it wasn't really a secret in any way if you look at standard textbooks or even for the address to the lay public at the time such as dr. Spock's baby and child care things were hadn't progressed much beyond that what he noted was that rich desserts the amount of plain starchy foods taken is what determines in the case of most people how much weight they gain or lose and in the British Journal of nutrition in 1963 dr. Passmore writes every woman knows every woman knows that the carbohydrate is fattening that is this was fairly common knowledge that is if you eat fattening carbohydrate it's not all carbohydrates but the starchy foods the sugary foods the sweets they are going to lead you to obesity and that was pretty well the prevalent thinking at his time things started to change in the 1950s and 1960s with the great so-called epidemic of coronary disease and what this was was as B industrialized what we noted was that there was an increasing incidence of coronary disease so in the 1950s dietary fat increasingly became vilified for its effect on LDL cholesterol the so called diet heart hypothesis and by the 1960s the American Medical Association was insisting that the so called low carbohydrate diets were fad of course they really were anything but a fad having been used for close to 200 years the vitriol was so extreme that John Mayer who is a prominent nutritionist of his time actually said that these carbohydrate restricted diets was the equivalent of mass murder we're killing people with these with these reducing diets the problem was this of course that if fat was the problem then you necessarily had to eat a high carbohydrate diet if you're going to eat low fat because fat and protein tend to travel together however the fattening carbohydrate could not be healthy in that it's low fat and unhealthy at the same time because it causes obesity so in order to resolve this cognitive dissonance all of a sudden the fattening carbohydrate suddenly turned into the healthy whole grain the fat with its dense calories was simply assumed to cause obesity even though there was really no proof anecdotal or otherwise to sustain that the model that we think about obesity instead of being the fattening carbohydrate model all a sudden became this calories in calories out model and that's where we were in the 1970s there was still a significant amount of debate of course between the dietary fat proponents and the dietary carbohydrate refined carbohydrate camp and this was settled not by scientific dispute but really by dictum by government in 1977 the US Department of Agriculture published for the first time this dietary goals for the United States and this was the first time really that any government institution had told Americans that they could really improve their health by eliminating or reducing the fact in their diets so this is a copy of the USDA Dietary Guidelines and what you can see very prominently is that you should avoid too much fat saturated fat and cholesterol and what you should eat is actually adequate starch so instead of avoiding the VDV fatty carbohydrates you should really eat more and this dietary fat controversy turned from a scientific controversy into a political one and it came down really on the side of eating more carbohydrates this explicitly determined goal was to raise the consumption of carbohydrates until they constituted 55 to 60 percent of calories and to decrease the fat consumption from approximately 40 percent to 30 percent and this is what gives us the very familiar food pyramid which is meats at the top x poultry fish you know weekly or even monthly and at the bottom what you should be eating every single day is bread pasta rice and whole grains physical activity of course is very important it got to the point in 1995 if you were to look at an American Heart Association diet but this is what they wrote to control the amount and kind of fad diet saturated fatty acids and dietary cholesterol you eat chews snacks from other food groups such as low-fat cookies low-fat crackers unsalted pretzels hard candy gumdrops sugar syrup honey jam in other words it really didn't matter how much sugar was in your snack or in your diet it only mattered how much fat there was so things like this which is candy is is is entirely fine to eat as long as you're cutting the fat so how did we do how did we do as a as a nation well it turns out that we actually did pretty well if you look at what happened we made a very conscious effort to eat less fat less red meat fewer eggs and if you look at the average fat consumption of Americans it decreased from about 45% of calories to about 35% if you look at what else we told them to do so you know get your blood pressure checked get your blood pressure treated to stop smoking to treat your cholesterol we did very well as well so 40% decline in hypertension 28 percent decline in hypercholesterolemia so it turns out we did very well so in fact you can't really say that the public wasn't listening to us in fact they were had listened to the advice of the time and tried really their very best to comply and they did we told them to eat less fat and eat more carbohydrates and that is what they did so if you look at the changes in the u.s. food availability you can see that butter eggs and and animal protein such as meat significantly decreased from the 1960s to today and what we ate instead was what we were told to eat grains and sugars if you look at the u.s. sugar consumption through the years you can see through the 1800's there's a steadily rising increase in the amount of sugar per capita that Americans were eating and this really reflects the increased availability of the sugar as sugar plantations kind of spread throughout the Caribbean and the u.s. south by the time you hit the 1920s you can see that there really is not that much more that we are going to eat and we enter a sort of flat period from the 1920s to about 1977 by the time they tell us that eating sugar is just fine you can see that there's this secondary spike in the amount of sugar that we eat if you look at grain which is the the most important of which is we you can see that in 1950 the per capita consumption was approximately a hundred twenty-five pounds per day and in the 1960s it decreased slightly in the 1970s decreased down to a hundred and thirteen but by 1980 had gone up to 122 by 1990 a hundred and forty one and two thousand a hundred and forty six total grain products shows a very similar distribution and what happened to wait well you can see that there had been a very slowly increasing incidence of obesity over the previous years but when you hit night if there's a clear tipping point right here in 1977 when they release the first Dietary Guidelines for Americans where you can see that the curve really changes that is instead of a slowly rising increase in the prevalence of obesity it takes a very sudden sharp turn for the worse so this is the way that we understand obesity now the reason we don't actually think about what causes obesity is because we actually think that we know what causes it and this is what we think so this is caloric reduction as primary theory that is it's all about the calories sometimes called calories in calories out so this is obesity and what causes obesity well it's clear that you either eat too much or you exercise too little and really those are personal choices or behaviors so that is the way that many of us think about obesity as it currently stands and there's a few implicit assumptions in that theory that you may or may not realize but a calorie the calorie that is calories of calorie of sugar is no different than a calorie of fat the fat stores are essentially unregulated that is it's simply a dump for excess calories of if there's the imbalance here it will be simply simply dumped into the body as as fact the intake and the expenditure of calories are under your conscious control that is we make all the decisions on how much we eat how much we exercise which sort of ignores the effect of hunger as well as basal metabolic rate but one of the more important assumptions to this theory is that the intake and the expenditure of calories are independent of each other that is to say if you eat more it doesn't have an impact on how much exercise you do if you exercise more it similarly doesn't have any impact on what you eat and we'll go through this to see if that actually is true and it's usually depicted as some kind of a scale that is this is the calories in calories out model if you you know have too much to eat or too little exercise it kind of shifts the balance and therefore you gain weight and usually what people say is that it's the so-called first law of thermodynamics and the accumulation of this fat is due to this caloric imbalance and this is true in a technical sense but it's not really as useful as you think that it is as an example if you go to an airport in March Break and it's really really crowded and you turn to your friend who's a doctor and say wow it's really crowded here and I wonder why that is and your doctor friend says well it's really very simple there's either too few people leaving or too many people coming in and while that's true it's not particularly useful the real reason more people are coming in than leaving is because it's March Break it's the same with calories yes in the end it always bound and boils down to calories but really the question is what's driving the calories in and what's driving the calories out and in our way of thinking it's a behavioral problem that is we control what we take and we control what we expend therefore it's a behavioral problem and of course it became a very popular theory in fact most of us still believe it today and it's because it is very easy to understand and it appeals to people's sense of self determinism that is your captain of your own ship and you're in control and if you are overweight really as a it boils down are you a glutton or are you a sloth and that's the way we think of it and obesity is not so much a medical condition but some kind of psychological defect some character defect due to low willpower or some some such some such assumption if you look at the text books in fact you will see that they are full of theories like this and full of what to do about it based on this caloric reduction as primary theory that is if you look at for instance Jocelyn's diabetes a very or authoritative textbook on the treatment of diabetes reduction of caloric intake is the cornerstone of any therapy for obesity of course it recognizes at the same time that low calorie and very low calorie diets none of these approaches has any proven merit the handbook of obesity dietary therapy remains the cornerstone of treatment and reduction of energy intake continues to be the basis of successful reduction again they realize that the result the results of such diets are known to be poor and not long lasting so even if you talk to experts they still say that reduction of caloric intake really is the basis of treatment so if this is the way we think that is caloric reduction is primary so this is the way things are then it's really a very easily tested hypothesis because if you think that somebody's obesity is caused by eating too much or exercising too little all we have to do is change how much you eat and if that is really the causal factor then we should see a difference in the obesity well just remember that the key assumption is that the caloric intake and expenditure are independent of each other it turns out that this is not a very new idea at all in fact it was done close to a hundred years ago where they took 12 men and put him on to these so-called semi starvation diets of 1,400 to 2,100 calories a day and what was found was that the subjects they did lose weight but they constantly complain of being cold and when you measure their basal metabolism what you see that there is a very significant decrease in 30% decrease in their metabolic rate and that explains why they're called the body was shutting down is turning down heat production as a way of reducing caloric expenditure so it turns out that you reduce your energy expenditure so much that if you go back to your regular diet after this period then what happens is that you start to gain fat you start to gain weight and they also measured all these things including decreases in blood pray blood pressure heart rate inability to concentrate all these are manifestations over the body really starting to shut down a similar study was done by Ansel keys in 1944 where he took 36 men and put him on a 24 week semi-starvation diet fifteen hundred and seventy calories a day and again measured what happened to their metabolism it turns out that the men's resting metabolic rates declined by 40 percent so again heart volume Trank heart rate slowed and the body temperature drop there's all kinds of psychological effects some people went actually completely crazy but they were obsessed about food and there was binge eating and all sorts of problems so what we see is that one of the key assumptions of the caloric reduction model is actually not true that is if you look at caloric intake and caloric expenditure they are very intimately linked in fact if you look at more recent data from the New England Journal of Medicine a very prominent medical journal from 1995 what they did was they measured something very similar that is they took people at an initial weight and they increased their weight by 10% or decrease that by 10% and what they did then is they look at what their basal metabolism is and what how they did this was they adjusted their diet I a liquid diet and they gave him more or the eighth lesson so they achieved what they wanted in terms of weight and what you found in terms of basal energy expenditure that is as you gain weight your body actually starts to rev up and starts to burn off those calories and as you lose weight your body wise you return to initial weight you go back to normal as you lose weight your body actually starts to shut it down so far from being completely independent of each other it seems that the body has compensatory mechanisms to actually return you to your initial weight and in fact these changes happen not only right away but they actually persist for a surprisingly long amount of time that is even a year after even a year after your weight loss so after a 10% weight loss this is from the American Journal of Clinical Nutrition after a 10% weight loss one year later what they found was that the total energy expenditure was already down and it stayed down so this goes down right away and it stays down if you look at the hormonal adaptation to weight loss this is a more recent study in the New England Journal of Medicine 2011 they took people and gave them very low calorie diets so 500 calories a day for 10 weeks and they're able to make them all lose weight so they wanted to see what happens after they lose weight well after a year what you can do is you can measure their harm hormone so gir Ellen the so-called hunger hormone is actually even after a year significantly higher than where it was before you lost that weight these ones peptide YY C CK they're all satiety hormones that is they tell the body that you're full and you can see that they are lower than it normally would be in response to a standardized meal if you look at their feelings of hunger you can see that this is the baseline and after a year of weight loss these changes have not gone away people are hungrier than they used to be and if you look at their desire to eat as much the same they are wanting to eat so in fact what happens to the body in response to weight loss is actually the body tries furiously to get you back to the original weight that is there are hormonal signals that tell you to eat that make you hungry and tell you that you need to return to your weight and if that doesn't happen well the body actually will start to shut it down because if you're not going to eat more the body has to shut it down in order to get that weight up so in fact far from being a scale the body acts far more like a thermostat that is there appears to be a set weight at which the body wants to be and if you go above that weight the body will try and bring you down as you go below that set weight your body wants you to raise up so this is what they found a 10% increase in weight actually led to a 16% increase in energy expenditure a 10% decrease in weight leads to a 15% decrease in energy expenditure so in fact these are physiologic changes which are aimed at increasing the metabolic efficiency and fuel supply of the tissues at a time of energy deficit that is if you're not eating enough the body will either shut it down or try and get you to eat more that is the body is actually very smart body fat is actually finally regulated and what do I mean the body is smart well think about this suppose you're the manager of a coal plant okay so I've depicted food as coal that's your energy okay and you run the power plant you need to put out energy and you have a certain amount in storage and you'd like to keep that amount in storage for times of need so what would happen if the manager of that plant all of a sudden you saw a 30% decrease in the amount of coal that you are getting it would you say well let's just burn the same amount of coal even though I'm getting 30% less the same amount and have the same amount of energy out when I exhaust my stars then we'll just shut it down we'll just turn it off well no that wouldn't be very smart you'd probably get fired what would you do you if you saw a 30% reduction in the coal that's coming in what you would probably do is turn down your powerplant 35 or 40% just in case there's further decreases in the supply of coal and the body does exactly the same thing because it's smart it doesn't want to die okay so if you have a reduction in the calories coming in the body's gonna think wow I need to start shutting it down I need to match what's coming in to what's going out so that I can maintain a reserve a storage reserve because if you didn't you just died so let's see what happens in the real world because really this caloric reduction model we've been testing it continuously and probably the biggest trial that's ever been done is the Women's Health Initiative dietary modification trial this was started in 1993 anyways a huge very expensive trial 50,000 women and they were enrolled to either a low-fat diet rich in fruits vegetables and fiber and about 30,000 roughly who just took kind of what they usually talk they use dietary counseling to make sure that people got what they thought they would get and let's look at what happened so if you look at total energy at baseline they were taking 17 hundred and eighty eight calories per day and I follow up they were taking fourteen hundred and forty five calories a day so they were taking three hundred and sixty 1.4 calories less every single day if you look at percentage fat they went from thirty eight point eight percent to twenty nine point eight percent which is very good that's exactly what they were trying to do and as a result the amount of energy from carbohydrate went up from 44% to 52% at the same time they to exercise more so if you look at the Mets per week which is a unit of exercise they went from ten to eleven point four in other words they increase their physical activity by roughly ten percent so that's great they ate less and they exercise more so what happened to their weight that's the question so compared to the people with a normal diet the people who took this very stringent 360 calorie reduction diet every day plus increased exercise they barely lost any weight compared to the usual group over a period of up to seven to nine years there was barely any difference less than one kilogram difference between the two groups it simply doesn't work so if you look at what they should have lost everybody says oh wow if you're reducing 360 calories a day and a pound of fat is 3000 you should have lost 36 pounds of fat in the first year alone but in fact their weight went from seventy six point eight kilos to seventy five point seven kilos which is barely a kilogram of weight lost but the problem with that is actually they lost lean mass as well as fat mass because if you look at their waist circumference it actually went up from 89 centimeters to 90 centimeters so the cruel hoax of all these semi-starvation diets are simply calorie restricted low fat calorie restricted diets is they do not work okay it has a perfect 35 year track record unblemished by success because caloric deprivation triggers two adaptive mechanisms which are going to work against you you're going to reduce your energy output and you're going to increase your hunger so in the end it's a self-defeating cycle they don't work and it's a cruel hoax because these women tried so hard for seven or eight years depriving themselves exercising for no benefit and they were just fatter than ever and this is the vicious cycle of under eating so as you eat less calories you start to lose a bit of weight your body says well hey I'm losing weight I need to control this so you decrease your energy expenditure and you increase your hunger but you still don't eat because you're trying to lose weight so you regain a bit but then you you you double down right you redouble your efforts and you eat even less calories and you lose a bit more weight but then the body says hey I need to decrease my energy expenditure further and increase my hunger and then as you start to gain weight you have to eat even less calories than that and it circles around and around until it's completely intolerable and then we blame the victim then we blame the person on the diet saying that you don't have enough willpower or you are cheating on your diet and you know it's it's all the health professionals they have all said that but it's simply not true that's not what happened it wasn't a lack of willpower if you think that eating too much is really the cause of obesity well again you can test that very simply if you give people more to eat then they should get fat and these experiments have been done as well ever since the 1960's most famously by a an endocrinologist by the name of Nathan Simmons so he took convicts out of Vermont state prison and he initially did it in college students but he couldn't make them eat enough so he took you know inmates where you could control what they ate and they were eating up to 4,000 calories a day and their weight would go up but then it kind of stabilized some wound up eating 10,000 calories a day and when you measure their metabolic rate their metabolism had increased by 50% the body was simply trying to burn it off again if we go back to the coal analogy if all of a sudden you're getting so much more coal you're not just gonna leave it you're gonna say well I have way too much coal let's burn it and that's what the body does if you look at this published in the American Journal of Clinical Nutrition they also took volunteers and they overfed them for 42 days okay and they followed a diet which is fairly standard for North America which is about 46% carbohydrate and what happened well they all gained weight but as you take them off of that force-feeding they all go back towards their usual weight except for this fellow who continued to gain weight but most people started to drift back down towards their natural weight naturally this is not of an experimental condition this is what they had did on their own so again you can see the body acts more as a thermostat not as a scale so the caloric reduction is primary there's a couple of problems with the way we perceive why we get fat the etiology of obesity one is that eating less does not result in weight loss that is it simply induces hunger and reduces energy expenditure eating more does not result in weight gain so if you try and over feed people what happens is that they simply burn it off until that condition resolves and then they go back to their usual weight so the body acts as a thermostat and the caloric deprivation is difficult because it's a fight against the mechanisms which have evolved to precisely minimize its effects that is we think that restricting the call will result in lower fat but it simply results in less power being burn less power coming out so we've got the wrong idea about the etiology of obesity that is we don't understand what it is that makes us fat and that is probably the single most important reason why we've been losing the fight against obesity the ultimate proof really is all of you because I think everybody in this room including myself has tried to eat a little bit less to lose weight and yeah it works in the short term but in the end it doesn't work in your hearts you know it doesn't work everybody knows it doesn't work yet that's what the experts still tell you but things are changing the other part of the caloric reduction model of course is the exercise more so one of the major things is that we say well if it's a not a matter of calories in it's a matter of calories out we need to exercise more so if you look at how much exercise we've been doing actually been doing more and more exercise if you look at leisure time physical activity we've been exercising more up until the 1960s in fact many doctors actually thought exercise was bad for you if you go back you know to heart disease patients they would prescribe a week of bed rest with the idea that resting is better than exercising so it wasn't until the 1970s and 1980s that people started to get the idea with the so-called fitness revolution that yeah we should be exercising a little bit more but prior to that it wasn't now experts routinely cleaned that exercising is actually the key to weight loss but the problem is that it's very hard to see any kind of correlation that is if you look at the correlation between obesity and exercise you can see that as we've been getting more obese more and more people have been meeting their exercise recommendations so it's hard to kind of reconcile those two facts if you go back to the real world and see what happens in the real world you can take this large cohort study published in JAMA 2010 that's the Journal of the American Medical Association and they took 39 thousand women and they grouped them into three different groups one which did very little exercise so Mets hour per week less than 7.5 a kind of intermediate group and a group that did really a lot of exercise and they wanted to follow them over seven years and see who got more or less weight so you can see that those who exercised less tended to be heavier but those weights were actually quite stable through the years that is over five six seven years of exercising more this is as much as an hour a day every day you can see that they don't actually gain anymore or lose any more weight than those who do zero if you look in this model of how much more weight you would lose by doing exercise over three years of one hour per day you would lose an average of an extra point one two kilograms or just about one quarter of a pound that's the difference in weight you would go from zero exercise to an hour a day so really very little at all and it hardly seems enough to be the key to weight loss a few years ago there this was published by church in the public library of science 2009 and what he did was he actually randomized women to several different groups you know of exercise so one that doesn't do very much to increasing amounts of exercise and what you can see is that there was actually no difference between all the groups but if you look more closely as you start to do more exercise you actually start to lose less weight if you look at other trials in fact almost every trial that's have been done has shown something very similar that is published in obesity 2007 they took a hundred men and a hundred women and they put them on six days a week of one-hour moderate to vigorous exercise and they wanted to see how much weight they lost so over one year so going from sedentary or zero exercise to an hour a day of aerobics you lost about three pounds for women and four pounds for men so yes there is a difference but really a very very small difference a group of researchers in Denmark actually took sedentary subjects and trained them to run a marathon with a thought that if a little bit of exercise is good for you while a lot of exercise must be good for you and the problem was that the men only lost about five pounds in weight and the women they didn't have any weight lost at all in fact they say that no change in body composition was that is if you think that well they lost fat but gain lean muscle well in these women they comment that they didn't see any difference in the amount of fat at all and this is from going from sedentary to running a marathon and this is the dirty little secret of exercise that nobody ever tells you about but it is really well documented and this is something called compensation that is almost all studies lasting more than 25 weeks people don't lose as much weight as they are predicted to weigh and there's probably two different mechanisms one is that as you exercise more you probably naturally increase your caloric intake and two is that as you do more prescribed physical activity your spontaneous physical activity probably goes down so if you look at this group from the church timothy church study you can see as that as they went and did more and more exercise you can see that they started to eat more and more that is they went from 1730 to 1831 to 1870 calories a day so as you're doing more exercise you're going to eat more compensation it can also occur because as you as you do more of the prescribed physical activity you do less outside of that and this is well documented in children this study was done looking at children and phys-ed in school so some schools of course had a lot of phys ed and some schools that didn't have much physical education and what they wanted to know was that our children more active or less active with that hour to a physical activity at school it turns out that when you measure all these kids it matters very little how much physical activity they get in school because those kids who are doing a lot of physical activity at school when they got home they weren't doing very much and those who didn't do very much at school when they got home they did a lot and that kind of makes sense basically if you go out and you go to the gym and you go run around the track and do weights for a couple of hours the last thing you really want to do when you come home and say hey maybe I should go for a little walk but if you spend your whole day in the office doing nothing you're gonna come home and say you know a bicycle ride around the block seems like a really good idea so there's a compensation effect and really it comes down to this yeah we'll go to the gym but then we'll take the escalator to get there and that's a possible mechanism of compensation the other problem with exercise really is that there seems to be this notion that exercise is the majority of our caloric expenses that is you can measure how much energy somebody expends just lying in bed all day and that's the basal energy expenditure so you can calculate it for instance for a 140 pound person just to sit down in bed all day it takes about 2200 calories per day if you were to get up and walk for 45 minutes a day kind of moderate pace of 2 miles an hour it would take about a hundred and two calories in other words that extra energy that you expend by exercising is barely four percent of your daily caloric intake so even if you go crazy on exercise you might only get up to 6% or 8% of caloric intake it's really a very small percentage of what we burn just to stay alive so the majority of calories that we expend through the day is actually not an exercise it's actually just heating the body and that explains a couple of things for instance why do we get so hungry after swimming probably not the exercise the exercise is important but we're constantly cooling the body the water is pulling off heat and as we burn off the as we pull off the heat we have to increase what we burn to heat our bodies back up and why do patients on these semi starvation diets get so cold well the answer is because they don't have enough calories so they're starting to shut down the easiest thing to shut down these your temperature so by focusing narrowly on this 4 percent of daily caloric expenditure and ignoring the other 96 is the reason why the exercise just isn't that important so make no mistake we should really all get exercise I actually believe that quite a bit it's just not that effective for weight loss so there are many many many important reasons to do your exercise there's the muscle tone the insulin sensitivity decrease vascular disease bone density there's all sorts of very important very good reasons to exercise the weight loss just is not one of the major things so we can see by looking at this hypothesis the way that we think about what makes us fat is that obesity is caused by eating too much and exercising too little is simply not true it simply doesn't hold up in an experimental setting then there's another theory of obesity which has mostly been forgotten but is being rediscovered and that's the hormonal obesity theory that is if we think about the coal and the power plant there's actually a little cop here a little traffic cop who directs things into storage and that's the first thing that happens when you take that energy you want to maintain that storage at a certain level the so called set point and the major player in determining how much food you keep in storage is insulin and to a lesser extent cortisol and then the amount that you eat and the amount that you expend in your basal metabolic rate will adjust themselves in order to maintain the setpoint of storage or fat so this is the way that we can think about obesity instead that is high levels of insulin or cortisol are going to lead to obesity and this is going to lead to the behaviors of eating too much or eating or exercising too little there's a few implicit assumptions on this theory as well for instance fat like all body systems are regulated under tight hormonal control that seems to make sense because there's virtually no system in the body which is not regulated it's not simply a dump the intake in the expenditure of calories are under hormonal control so this takes into account the effect of hunger for instance and the basal metabolic rate and the intake and the expenditure of calories are directly linked to each other as we've seen and not independent so insulin is i've been used as a fattening agent first quite some time in 1923 it was first used as a for underweight children and in the 1930s clinicians had started to use that already for pathologically underweight children and when they gave insulin these kids would gain weight and the truth of the matter is that I can make you fat I can make anybody fat what do I do I give them insulin and any physician who's used insulin or any patient who's used this thing knows this to be true it has nothing to do with character defect or lack of willpower when you take insulin you get fat so if you look at this study which is from the diabetes trial a type 1 diabetes the DCCT trial you can see that they had two groups so one group of diabetics they actually had very tight control of their Sugar's by giving more insulin and the other group of patients they had very loose control because they that was the trial at the time and what you can see is that the number of people with a major weight gain was significantly different between the two that is the number of people who are using more insulin almost 30 percent of those people had weight problems major weight problems compared to those who didn't use so much insulin if you look at the amount of weight they gained and correlate it to how much insulin they use you can see there's a very strong correlation that is the the total insulin dose as it goes up is correlated very strongly with the amount of weight that they would gain if you look at type 2 diabetes you actually see much the same thing if you do intensive control of their diabetes by giving them more therapies that increase their insulin levels they tend to gain more weight those ones that you don't control this tightly they don't gain as much weight in type-2 diabetes they had a trial a few years ago when they're really concerned about controlling their glucose and what they found was this they took a group of people a group of diabetics and they gave them intensive insulin therapy and they went from zero units of insulin a day and six months they had them up to a hundred units a day of insulin and what happened well they all started to gain weight and you can see that again there's a very tight correlation between the amount of insulin that you used and the total weight gain in fact the other interesting part about the study is that they gained on average eight point seven kilograms but they also measured how much calories they're eating so at baseline they're eating 2023 calories by the end they're eating 17:11 calories that is even though they were gaining weight they were eating less and less that is they had reduced the amount of calories consumed by almost fifteen percent yet under the influence of insulin which is telling the body to get fat they were still gaining weight if you take a look at diabetics and give them different amounts of insulin to control their diabetes again in this study from the New England Journal of Medicine in 2007 you can see your body weight goes up as you take more insulin and it correlates to the amount of insulin that you get that is these are different types of insulin but as you get more insulin that is a higher dose of the insulin you get a higher weight gain insulin itself can cause local fat deposits and this is a picture of something called insulin lipo hypertrophy which is the way that the insulin injections can actually cause localized deposits of fat if you combine insulin with other agents that increase insulin you can see that you get so it's a funnel urea which is a drug which increases insulin levels if you combine that with insulin the insulin levels are going to go up even higher even though your sugars are better you're going to gain more weight a new class of drugs called die Glocke losen works in a different way now you can add this to insulin to reduce the amount of insulin that you need and what they did was this they had four different groups so one group was just the insulin group and this over the study period these people to control their Sugar's were getting more and more insulin and these people instead of increasing their insulin they were taking different doses of this new drug which didn't raise the insulin levels and if you looked at the change in weight you can see that those are taking more and more insulin are gaining more and more weight and those that are taking less insulin are losing their weight and you see the same thing in type 2 diabetes with metformin metformin is a drug that does not raise the insulin levels but controls the sugars and you can see that there is no difference between metformin and the control group in terms of weight gain whereas glyburide which is a drug that does raise the insulin level does cause the weight gain weight gain is independent of the control of blood glucose because you can use these different drugs such as metformin so the metformin group loses the most weight but as you take drugs such as so faunal urea you actually gain more and more weight januvia which is a new type of drug which also doesn't raise the insulin levels all the time is not associated with the weight gain in fact causes a little bit of weight loss compared to the older medications which simply raise the insulin levels and this is the same sort of thing with the doctor glyph losen as you add it to the body you actually start to lose more and more weight and not only is that weight but you can measure it and see if it's fat tissue or lean muscle tissue and much of that weight loss is actually fat tissue so you can actually make a graph excluding the the t set D class but you can make a graph of drugs which increase the basal insulin the insulin and the sulfonylureas and you can list a number of drugs that don't cause such a sustained increase and insulin levels and if you look at what causes weight gain it's almost the exact same list that is the insulin and drugs that raise the insulin levels cause weight gain and those that do not raisins levels insulin levels do not cause weight gain and the reverse is also true if you take away the insulin people will lose weight this is a picture of untreated type 1 diabetes that is these are people who due to an autoimmune effect actually have very very low levels of insulin and what you find is that they are skinny beyond belief in fact the classic description is a melting down of flesh and limbs into urine and no matter what you feed them no matter what you give them to eat they still can't lose weight they still can't gain weight they will continue to lose weight until they die when you give them the insulin back all of a sudden they gain their weight back and this is actually fairly well known in the type-1 community and it's actually called daya bulimia that is a deliberate underdosing of their insulin in order to lose weight so it's dangerous as hell and can kill them but they know that they will lose weight so they give them less insulin that is insulin causes weight gain you can do the same sort of analysis with cortisol that is if you give people cortisol which is a stress hormone they will gain weight so we can do that from a pharmacological standpoint by giving them steroids or a drug called prednisone and they will gain weight almost everybody gains weight in fact anybody who has treated patients knows he'd give the steroids they gain weight there's also a condition called Cushing's disease where people over produce this hormone cortisol and they also gain weight the hallmark of Cushing's syndrome is weight gain and if you don't have cortisol it's a disease called Addison's disease and again one of the hallmarks of Addison's disease is weight loss so you can see that really what caused weight gain and weight loss is not calories per se it's really hormones because as you manipulate insulin as you give more insulin they will get more as you give less insulin they will have less weight and the same with cortisol so if you say what is making us fat is it because we eat too much or exercise too little well that doesn't seem to be the case at all in fact it's hormones obesity is really a hormonal dysregulation of the fat and those two hormones are predominantly insulin and to a lesser extent cortisol so this is the caloric reduction as primary therapy as primary theory and you can see that this is really not true because when you think about it it doesn't really work because manipulating the eating doesn't lead to changes in weight but the belief in this theory has led to a singular research focus on so behavioral and psychological issues that is is a lack of willpower is it fast food is it the sugar and an entire generation of health professionals really endorsing this are so-called low low fat caloric restriction as a treatment well if you have the cause of it wrong you simply can't understand the treatment and really as I said it's a perfect record unblemished by success so this is the hormonal theory of obesity which is how we understand it that the high insulin and to a lesser extent cortisol levels leads to the obesity and by changing these hormones that that actually leads us to these behaviors of eating more or exercising less in other words this is not the cause of obesity it's actually the result of obesity and that really sets you up for the proper question because the proper question then is if this is the result of obesity what is the cause and the cause leads you back to the hormones so in other words you're not getting fat because you're overeating you're overeating because you get in fat that is this is the result not the cause so now if we understand now we can start to treat it so the really the real crucial question obesity is not how many calories am i eating because the calories are larger the aroma if you take more calories your body will burn it off if you take less calories your bodies will burn less it's what is driving my insulin levels up and the first thing that was noticed is that it's the fattening carbohydrates so all those sugary foods starchy foods are fairly well known to cause high insulin levels and over time that leads to obesity which leads to the behaviors of overeating and under exercising so the answer really or the first one that we've come up with is the fattening carbohydrate so if you go back to Banting so this is not a new idea in fact it's a very very old idea in fact most of our grandmother's if you had asked them how to treat obesity the first thing they would have said stop the sweets and stop the starchy foods that would have been the first answer and that was what it was the fattening carbohydrates leads to obesity and as we see it now the fattening carbohydrates leads to the increased insulin levels which leads to the obesity so really there's the body acts as a set point that is it's not a scale it's completely wrong to think of the body as a scale a calories in calories out scale it is much more useful to think of the body as a thermostat that is what is setting my body weight setpoint why am i setting it too high and how can i reset it to the bar to to a proper level and really insulin or hormones are the major way that it resets insulin tells the body to get fat and if you take it away it will reset it down so this leads us to again a very very old idea this was taken out of the practice of endocrinology in 1951 that is if you are going to try to lose weight there are foods that you need to avoid there's bread and everything else made of flour cereals including breakfast cereals and milk puddings potatoes and all other white root vegetable foods containing much sugar and all sweets but on the flip side there are foods you can eat as much as you like that is meat fish birds all green vegetables eggs dried or fresh cheese and fruit if unsweetened except bananas and grapes and this in a nutshell is just something I found on the internet which kind of explains carbs insulin for dummies and what it is is it takes a normal person and as you eat the bad carbs the insulin levels go cuckoo the black box gets asked up if you take an obese person and you simply cut their carbs the insulin levels will normalize and the black box is fixed so as these are not really new ideas but by trying to understand what is the really the ideology of obesity you can get much more rational treatments of obesity that that fall more along physiological lines and this is the final slide I have this is the weight loss and nutrition clinics which we're running if there's any questions I can be reached that dr. Jason Fong at hotmail.com thanks

Channel: Jason Fung

Views: 758,473

Keywords: obesity code, obesity, Diet (nutrition), Insulin Resistance, weight management, calories, Low Carb, weight loss, calories in calories out, hormones, Exercise, Wellness, fat, Dieting, Nutrition, fat loss diet, Fasting, Health, Carbohydrates, Dieting (Symptom), Insulin, medical, Loss, diet, Weight, drjasonfung, drfung, fung, obesity in america, obesity epidemic, Obesity in Amercia, obesity code dr jason fung, Obesity code boook, weight loss tips

Id: YpllomiDMX0

Length: 58min 50sec (3530 seconds)

Published: Fri Mar 01 2013

Reddit Comments

[u/Inti108]

Thank you, this is a really good talk, I thought I knew what it was going to be about, but I learned a lot.

But why is he wearing a stethoscope? Is he really trying to nail home the fact that he is a doctor?

[u/dlg]

Dr. Jason Fung gives an alternative explanation for the causes of obesity and ways to treat it.

He is also the author of the book which covers the same ideas, The Obesity Code

Here is the rest of the lecture series:

The Aetiology of Obesity Part 2 of 6: The New Science of Diabesity

The Aetiology of Obesity Part 3 of 6: Trial by Diet

The Aetiology of Obesity Part 4 of 6: The Fast Solution

The Aetiology of Obesity Part 5 of 6: Diet and Disease

The Aetiology of Obesity Part 6 of 6: Dietary Villains - Fat Phobia