He does not believe in common sense, he believes in data. I believe in both.

Dr Lustig said repeatedly that he does not believe in common sense but he believes in data. You could hear it in several of his lectures of which one was in this video, when he said it at 18:00 minute. The background behind this statement was the obvious conclusion we make that when people are less physically active, it is their responsibility while his alternative explanation was that it was their physiology that made them sloths and therefore not their fault as such. 

Dr Lustig presented a common sense as a dogma which was in opposite to research, saying that that if we knew everything already we would not need to do the research. Is this really the common sense? What wikipedia says about this term? 

"Common sense is a basic ability to perceive,  understand, and judge things..."

I consider myself a scientist, too, but I believe in common sense and also in data - but only when they are presented in the whole context, not cherry-picking those that favor my agenda while leaving the rest out and muting the common sense so that one is not able to spot the flaws in the INTERPRETATION of the data. A common sense should be a sort of assessment whether the sense we make from the data actually fits the real world. And because I have been doing this all the time, I have decided to write this blog to debunk the selectively presented data of Dr Lustig after a careful judgement of the perceived and understood content of what he has been presenting to people over the past 5 years.

Dr Lustig has also earned the critiques elsewhere so I am not alone but I am probably the only one that tried to debunk his claims at such a wide scale as you could see in my blog. You could read my attempts to debunk his numerous claims in the previous 32 articles of this blog and on my very own website. 

To cut this short I would like to relate this post back to the example outlined at the beginning: that it is the physiology that makes people sloths and gluttonous, not their initial actions - hence they are not responsible for how sick and unhappy they are. The data he has presented strongly suggest this mechanism, but me and my common sense reach further to the past and says this:

In the past, our ancestors were simply forced to expend the energy in search for food or earning the living. They also often went hungry, so they also experienced the lack of energy due to the physiology - but there was no other way to survive than to overcome this and go and seek the food. Today the technological advancements allow us to earn living and spend our free time without the need of expending extra energy. The technological advancement and food almost waiting for us at our doorstep actually encourages us to be physically passive. We are encouraged to focus on our mental stimuli and reward, forgetting about our bodies, which simply sit or lay down for hours each day. It is only when this continues for a long period of time that the metabolism is changed and the physiology is harmed by the excess calories in and almost no extra calories out except of what we need to burn to stay alive. Only then we can see how people develop insulin resistance and fail to read leptin which further exaggerates the problem. Only at this point I can join the argumentation of Dr Lustig that it is not the peoples fault and that their biochemistry is taking control over them. 

But until then it was our own choices to sit and play a video game and to reach for fat and sugar laden processed food instead of going for a walk and biting into an apple or some other nutritiously superior food. When I go to the supermarket, in most of them I am welcomed by the fresh produce - in England, I do not know how it is in the U.S. I firstly start putting the fresh produce into my basket or trolley. There are isolated places at the entrance with the promotional products that offer the processed food stuff or laundry detergents or nappies, but in principle we are all welcomed in our supermarkets by the fruits, vegetables and salads based on various sorts of lettuce. We do not come to the entrance, grab the cake and leave, do we? 

The same is on the streets in front of many local shops: there are boards and desks with a number of bowls full of fruits or vegetables for £1. You have to go inside the shop to get the chocolate, beer or a bag of crisps. Now tell me that most of us do not have a healthy choice? 

I agree that there are food deserts and many people do not have a drinking water running from their tap, but these are the minority in the developed countries. I sympathize with the poorer countries in which the drink industry rather sales (and their governments allow this) the Coca-Cola instead of plain water. They are really not responsible for their choice. But for the most of us int he U.S. or the UK this is not the case. 

Another such case of wrongly presented information (not just data) is the suggestive conclusion put into the mouth of the beverage industry that the industry has never actually said - that all calories are the same and therefore a calorie is a calorie - as Dr Lustig repeatedly said in other lectures when presenting this slide: 

I have written a post about this already but I would like to bring it up again here for you to see that the common sense really matters in terms of the perception, understanding and judgement. The Coca Cola company admitted in their statement, that ALL OF US (including them) have to take an action to beat the obesity and that All calories count, regardless of their origin. There was said nothing about the quality of the calories and how they behave in the body. They simply admitted that the sugar calories in the drink also matter, as do the sugar or other calories from food, because people often ignored the calories in the drinks and only focused on the calories in their food. Coca Cola made it clear that their sugary drinks also contribute to the obesity and therefore they provided an alternative - artificially sweetened drinks. 

Therefore, the claim of Dr Lustig that the food industry said that the calories are all equal from the perspective of metabolic pathways is unwarranted and wrong. The drink industry only admitted that their calories also count and that they play their part in the current trends of ill health of the nation. Nothing less and nothing more. Meanwhile, I am not sponsored by any food or drink company, just to dismiss possible worries of my readers. I also have NO disclosures. I just want to be objective and factual as much as I possibly can. 

And this is the end of my discussion on the data and common sense. Any computer will read and evaluate the data, but only humans (for now) have the common sense to give it the actual meaning - or to distort it towards their own interests.

I will keep using the common sense when listening to the presentation of data by the biased presenters and so should you. 

Which carbohydrate?

You could hear Dr Lustig repeatedly saying in his many lectures that we eat more sugar and that the fat intake has gone down. I have already debunked this claim, but I would like to return to it and demonstrate how sophistically you have been manipulated into thinking that it is only the sugar that has been behind the increasing prevalence of obesity and metabolic diseases.

At 22:56 minute you could (again) see this picture: 

SnackWells. I want you to focus on the figures at the bottom of the slide. You can see that the fat has been reduced in this product by 2 grams but the sugar has increased by 4 grams. Now, let's calculate: 1 gram of fat has 9 kcal whereas 1 gram of sugar has about 4 kcal (the metabolisable energy can differ, some sources use 3.75 kcal). So if the energy content of biscuits was lowered by 18 kcal, the sugar brought back 'only' 16 kcal. Was that all? 

How much the non-sugar carbohydrate has been added in the new 'healthier' version of the biscuits? It was additional 9 grams of substance, which was mostly starch in this case, hence a glucose based carbohydrate, contributing by additional 36 kcal. So, while the sugar substituted the fat with slightly lower amount of calories, the addition of other carbohydrate - starch largely exceeded the contribution of sugar calories and made the new product significantly more caloric than the old one. And now you can think: was it really the sugar fault or rather the starch? You were not told this detail although it was right in front of your eyes. Sugar went up while fat went down and that was behind the obesity and metabolic diseases of Americans. 

Why the starch contribution to calories has been ignored? I tell you why: because of the anti-sugar, or rather the anti-fructose agenda. You could repeatedly hear Dr Lustig saying on several occasions elsewhere that glucose is good, that every living organism needs it while fructose is a poison.

This biscuits example reminded me the general trends of the macronutrients (energy) consumption of the Americans over the decades. Look at the diagram I made for my dissertation work, based on the USDA data: 

Can you see the trends and what was really been happening? Up to year 2000, both sugar and fat consumption were on the rise, slightly, but rising. In comparison to them the calories from starch increased much more. And here comes the dual scenario: while the fat consumption has been rising in grams, its % of calories of the total energy intake decreased, because the consumption of total energy has increased MORE than the fat calories. But, from the diagram, it is apparent that the same happened for sugar.

And now tell me: did Dr Lustig keep saying that the fat consumption went up or down and what he said about the sugar? Something completely different, right? His claim was based on a selectively chosen data between two dietary surveys back to 1989/91 and 1994/5. There he either reported the increased sugar consumption in one case, or in another he compared the % of fat calories (going down) while the obesity prevalence went up. At some moment he admitted that the fat consumption went up by 5g, saying that it was nothing. But this detail was buried under his continuous focus on sugar and fructose further on. He never put the sugar and fat together like in the diagram above, except of using a single product like the SnackWells. If he did that, his anti-fructose agenda would be gone. And did he ever mention starch? No. Do you remember him saying a DONUT? He did not comment on processed starch - white flour from which it is made of. He used it as an illustration of combination of sugar (containing fructose) and fat only. Sugar and fat eaten together certainly are not healthy, but so is not the processed starch consumed along. But glucose is our friend, do you remember? WRONG.

Does this need any more comment, especially in the light of my first articles in this blog where I debunked his outdated information which he presented as current trends? 

Although Dr Lustig tried to dismiss the USDA data source in the past, saying that he preferred the NHANES data, the same trend in the consumption of sugar and fat has been confirmed by the NHANES and I have produced a detailed discussion on these in one of my other articles here. 

One more thing I would like to correct in that slide at the beginning. According to my knowledge and based on the reports freely available in databases, the HFCS-55 is mainly used in the drinks whereas the baked goods and confectionery tend to contain HFCS-42, hence containing only 42% of fructose, not 55%. The overall content of the fructose in all the examined added sugars was estimated to fluctuate around the 40%, because other sweeteners were used in the processed foods, such as dextrose, which contains no fructose. Therefore the remaining 60% was provided by glucose. So whenever the sugar/HFCS consumption has increased and the fructose within, glucose consumption also went up and this was still within the sugars. Add the even higher increase of glucose from starches, mainly the processed ones (donut, without the fibre), for which the data also exists, and you get the picture of what has been happening over the decades. 

So, now you have the true answer on the question: WHAT CARBOHYDRATE? 

- GLUCOSE.

How much? 

- TOO much. 

What happened to fat? 

- It also went UP and kept going up all the time in absolute amounts. The relative percentage of calories is not important here and it was only used to mislead the audience towards the picture it was wanted to see. 

Fast food nation = fat nation

After I showed an example of how people easily lose weight when ditching takeaways, arguing that it is more rich in fat than sugar, I experienced a deja-vu when found this image online: 

I remember seeing this in the Metro papers several years ago and kept it in mind every time when I faced the situation of having takeaway. Can you see sugar anywhere? And if there is some - how much? 

If you could not read the text, those glasses which look like wine represent amount of FAT in each of those selected takeaways. 

Moreover, this kind of food is not only rich in fat, it is also rich in starch (glucose) calories, whether from the fries, pizza dough, rice or fat laden breading of the fried cod. Little or no vegetables other than potatoes. You can find only minor amount of sugar/fructose in there, if any. And when it comes to soda, many people, especially obese ones, reach for a diet version. Yet they do not seem to get slimmer and I do not wonder why.

Exercise for weight loss does not work?

At 14:12 of Dr Lustig's lecture you can see the diagram of one meta-analysis which assessed whether there is the body of evidence that physical exercise helps to lose weight. Dr Lustig presented it in a very simple manner - not saying how long the exercise lasted, what the exercise actually was, how many calories equivalent it was to balance a daily energy intake, and so on. All these factors are important in evaluating why something like this works and why not. 

And that is exactly my point here. WHY exercise does not work to curb down the obesity levels? They say there was a small weight loss overall but it was presented as a negligible effect. Nothing was said about whether the people had also their diet altered or not and what their diet consisted of, in general.

Let me put it this way: when you are obese because you consume over 1000 kcal more per day than are your actual requirements for that body size and lifestyle, how long you have to exercise to burn this extra energy plus some more to achieve the weight-loss? 

Here is a brief overview where you can find that if a 68 kg weighing person performs light aerobics, within a half an hour they burn mere 120 kcal. That is not even half of a regular Mars bar in the UK! With the higher body weight the energy expenditure is higher, true, but is it that much? 120 kg heavy person burns around 200 kcal. Still not a regular Mars bar, which contains 260 kcal. How much was that burger? Over 1400 kcal.

How long DAILY can you expect an obese person to perform even light exercise? Not for 3.5 hours to burn off that extra burger calories, would you? And this is every day because they tend to overeat every day, some even double or triple the average energy requirements (extra 2000-4000 kcal) as I have seen in my favorite series Supersize vs. Superskinny. Watch it, it is eye-opening. Available on Youtube.

Any wonder why the exercise showed such a small result? And this is also why the first law of thermodynamics seems not to work here - because in such a high energy intake you cannot expect weight loss if the energy output is not exceeding it. Moreover, it needs a substantial amount of time to achieve significant results, which most of such studies do not have. They usually assess the participants over several weeks or a few months at their best. 

Therefore, the things have to be looked at from the whole perspective, not just looking at the data and dismiss this or that saying it is inefficient. The little success (half point of BMI as Dr Lustig said) actually has proven that the exercise works, but it has to be accompanied with dietary changes as well. It is generally easy to overeat when the food is so cheap, processed and palatable. Cheap processed food is very energy dense, which means that per 100 grams you can get more calories from the processed food than from the unprocessed, such as fruits and vegetables. And these calories are not always only sugar. Most of the time there is more fat calories than sugar calories. Add little salt and you have got a deadly trio that has the potential to make people addicted to this particular diet. 

Moreover, the exercise has been found to be very effective in decreasing the risk of metabolic diseases such as type 2 diabetes. In fact, the exercise alone was found to be even more effective than the dietary changes alone. Surprised? I am not. It has its rationale based on our physiology. It is very simple: when you over consume, you store the energy not only in the fat, but also in the muscles and liver. Especially muscles are responsible for the most of the insulin mediated glucose uptake in the body. When you overeat and have a sedentary lifestyle or remain bed bound for several days, they are kept in the 'full of energy' state during the day and cannot take in any more. In excess, the glucose, instead of refueling the muscles, keeps circulating in the body and the body keeps producing more insulin to fit it somewhere as it should not stay in the blood in high concentrations. And humans have quite a low capacity for the de-novo lipogenesis (DNL) as you could see elsewhere. There are other processes that happen in such a hypercaloric state but this is the main mechanism. Once the person starts exercising, the muscles burn the energy they have and start taking in more again which results in the drop of a high blood glucose and also blood lipids. That's it!

We as a species have evolved being physically active and that is the need of our physiology today, too. Stop being active and the consequences come. Plug the hole in the sink and it will soon overflow. As long as one or two days of being bed bound with excessive eating can lead to the changes in our biochemistry indicating a pre-diabetic state. Keep doing the exercise while overeating and you will just keep gaining weight while you will most likely remain metabolically healthy for a pretty long time. Just please do not take this as my approval to overeat, OK? Healthy weight also matters. 

And finally: look at the diagram above again. The plot contains the results of different studies. Some worked, others did not, when examining the effectiveness of exercise on the weight management. It was only the overall figure of pooling all these together that Dr Lustig presented as the small and negligible difference. At least three studies (towards the left from the vertical line expressing that mean results) showed quite a success, did they not? I would have to look at each of them individually to give you a full report what made them show the effect and what not. But even from this you can see that it really depends on the circumstances whether the exercise does work or not. The first law of thermodynamics still applies here and the exercise DOES work when the energy output exceeds the energy input on a regular basis.  

One more thing I have noticed when listening the lecture further at the minute 18:55:

Look at the right column Activity. So, if the lowered level of activity has contributed to the obesity epidemics and associated metabolic diseases in children, why suddenly the physical activity does not seem to work, according to Dr Lustig? Yes, he did question this aspect and went for the usual toxic substance (fructose) in our diet after that but it is generally accepted in the scientific community that physical activity does play a role in the weight management and overall health of people and it is usually advised and promoted by the health authorities and implemented into the government policies, too. Dr Lustig provided no sufficient evidence that the physical activity is negligible or does not work in maintaining a healthy body weight, except of the meta-analysis study mentioned earlier. 

To be on a neutral side I must say that other studies also concluded that the exercise has little impact on weight loss and the change in the diet produces a higher effect, but this was only because of the insufficient balance of the calories I have discussed above. It is more effective not to eat that chocolate than trying to burn it off.

I know it from myself: I have been maintaining a lower body weight for some time now, with tiny fluctuations in one kilo up or down. And I know that when my physical activity suddenly increases for a couple of days while the diet remains the same and balanced, my body analyzing scales notice this and also estimate a lower percentage of body fat in my legs while increasing the percentage of water and muscles. I need no further evidence that the exercise works. I assess my body composition regularly. I maintain a record and do it at pretty constant conditions. The measurements were consistent, sometimes two or three days in a row produced identical results. 

And here I come to the last point of this article: there is a difference between maintaining a healthy body weight and reducing the body weight of obese people. These two premises are quite different, because when you are of a healthy weight, it requires less effort from you to exercise and you also need to exercise less to keep the energy in balance. For obese people this is particularly difficult to do on a regular basis and the drop-off rate is also very high, which contributes to the failure of such programs. What may be a light aerobic exercise for a fit person, for an obese person it can become quite a burden after 5 or 10 minutes. Now, imagine them doing this for an hour to merely burn the single Mars bar... 

But, as one large supermarket chains advertises: 'Every little helps'. The burned 120 or 200 kcal means they were not deposited in the fat stores and the muscles are now ready to take more glucose and more fat from the blood stream, reducing the risk of type 2 diabetes. Remember Dr Lustig saying that obesity is not a problem and that 20% of obese people are metabolically healthy? Well, 80% are not and physical activity has a huge potential in helping them out of this doom. He also admitted this in another video at 1:18:05 time that he has been struggling with his high body weight and the diet, but that the constant physical exercise helps him to reduce the abdominal fat deposits but his body weight does not change that much. He is simply replacing the fat with muscles. And if the studies do not examine the change in body composition of the participants but instead they only use BMI for the assessment, is it such a mystery they do not find significant changes? 

Was the causal effect between the sugar consumption and diabetes prevalence confirmed?

Please make yourself comfortable, this also will be long.

This particular article aims to comment on the effort of Dr Lustig to convince the audience that he has proven the causative link between the diabetes incidence and sugar/fructose consumption. It is not aimed to contradict the found link.

Dr Lustig proudly presented the study in which he participated and its design at 31:34 minute: 

He explained why it is so great and what they have examined. It looks good so far. They even mentioned the oils in the food supply, which is a surprise after the previous attempts based on the EPIC InterActive analysis that failed to mention this at all. 

He also announced they estimated that sugar explained 25% diabetes cases worldwide:

Similarly, he said that 29% of diabetic prevalence in the U.S. is explained by sugar and sugar alone, irrespectively of its calories and irrespective of its effect on weight. My critical mind is asking: what about the remaining 75 or 71%? This was not explained. 

After reading the original study I can tell you that they did a hell lot of analysis and statistical tests. I am not going into depth of the details. What I would like to say is that there were so many limitations, mainly about the quality of the data from all named sources, that even the team ended their discussion with this: 

...any of the findings we observe here are meant to be exploratory in nature, helping us to detect broad population patterns that deserve further testing through prospective longitudinal cohort studies in international settings, which are only now coming underway.

Therefore, although they found statistical significance in the link between the sugar AVAILABILITY (not consumption) and the prevalence of diabetes, independently from the BMI or total calories availability, even when adjusted for other potential confounders (including fat), this was just an extensive statistical analysis of the data of a limited quality, despite allegedly being the best they had at that time. 

Moreover, the basic rule, which is taught in the first epidemiology lecture, is that the causation effect cannot be obtained from the observational data and based on the associations as this particular study was. So what causation effect was Dr Lustig talking about? 

Oh yes, the Medical Causation Inference, or causation inference in short. What do they say about it? 

Causal inference is the process of drawing a conclusion about a causal connection based on the conditions of the occurrence of an effect. The main difference between causal inference and inference of association is that the former analyzes the response of the effect variable when the cause is changed. The science of why things occur is called etiology: the study of causation, or origination.

From this it emerges that all he did (and he also said it) was that he expanded on the single snapshot of the EPIC study correlations with the 10 years long temporal relationship (still based on associations) that the changes of diabetes prevalence followed the previous changes in the availability of sugar and not the other way round. Nothing else. This may have captured the causative effect or it may have not. 

Here is more information about what the inference actually is. So even if they statistically found a seemingly causative effect, it came with the discussed limitations and the nature of the data (observational) and therefore it is not a solid proof about the true causative effect. And, as they said: this is only the beginning and the hypothesis outlined here needs further testing by longitudinal prospective cohort studies. 

Although I said I was not going into the details of the study, I would like to highlight one point of the announced Bradford Hill Criteria, which was not included in the four points Dr Lustig mentioned. The strength. Look at the diagram:  

Despite the link between the sugar availability and the prevalence of diabetes among all these countries was found to be statistically significant, the strength of the correlation coefficient looks quite low. The direction of the scatter plot seems to have very small angle against the x-axis, but this was calculated by the computer, so let’s accept it. The low strength here does not mean the causation is non-existent, but the higher coefficient means that the causation is more likely, according to the Bradford Hill criteria on the Wikipedia. This was just to highlight another weak point in the conclusion for the causal effect of sugar consumption on the prevalence of diabetes. 

Many scientists often stick to the statistical significance and push this finding through, despite the correlation coefficient is often found small. And, just for the comparison: try to recall the critique of Dr Lustig towards the scatter plot of Ancel Keys. He had an apparently stronger association between the fat intake and coronary heart disease mortality, did he not? Yet that much stronger coefficient was named as VERY MINOR by Dr Lustig. How would you then evaluate the one above? Moreover, Dr Lustig criticized few outliers in the Ancel Keys study, but here you can also find a few.  

One thing came to my mind: the links between other factors (dietary, lifestyle, economic) with the diabetes were found either statistically insignificant or non-existent. For those that showed some link, albeit insignificant (there is a difference between the statistical significance and clinical relevance), I would be curious to find out whether some of these also would come out positive in the causation inference test. This was not done.

And finally: at the 36th minute you could hear Dr Lustig saying that "this is proximate cause". And here you can learn the difference between the proximate and ultimate cause. The proximate cause that the ship is sinking is the hole in its body below the waterline, but the ultimate cause was that it hit a rock that made the hole. And, as Wikipedia says:

"Separating proximate from ultimate causation frequently leads to better understandings of the events and systems concerned."

So we now have to find the ultimate causation, since we already have the proximate one (or we think we have it). How? 

We now know that their statistical analysis found other individual factors (dietary, lifestyle, economic) as insignificant or non determining in the relationship with the diabetes prevalence. Maybe those 71 and 75 unexplained percents are needed to be explained? What factors do they refer to? Maybe a cluster of various factors that are naturally present with the actual sugar consumption (not average availability per capita). Examining each of these other factors separately might not give the objective result, because in reality we consume composite foods within a certain lifestyle and they interact in the etiology of the disease. Where some may not come up significant on their own, they may help other factor becoming significant, or these coupled together in real living conditions, especially when they commonly occur together in the society with increasing prevalence of diabetes, or any other metabolic disease. And now even Dr Lustig knows that a 'donut diet' (sugar and fat) coupled with the lack of physical activity and positive energy balance is detrimental to our health. Yet their analysis points only at the sugar and sugar alone, but only within about the quarter of the diabetes cases prevalence.

Finally, later during the lecture, at 56:20 you could hear: 

"90% of what we know in medicine today is causal medical inference. Only 10% is scientific proof."

Well, I did not know that, but OK. As I said at the beginning, this article was written to comment on the claim that we have a proof about the causal influence of sugar only on the diabetes prevalence, independently of the factors that were already discussed. I have no problem with accepting it if it was correct but there is still a space for doubt and that was my point. Unless we will do a proper scientific study (which we will not do in this case for obvious reasons also outlined by Dr Lustig), we can only say: this is the best we have and it looks solid. Not that it IS a definitive evidence. I still have a sort of feeling that dietary fats consumed along sugars in excess do have a significant impact on the development of insulin resistance and also other metabolic disruptions. 

Remember that liver is the major organ for energy metabolism and it not only metabolizes fructose but the dietary fats as well. 

Now I would like to cite my own work based on similar analysis of dietary patterns worldwide, performed by Popkin et al  2012: 

"...the worldwide trends, the increase in obesity, MetS, CVD and other metabolic illnesses between the years 1962 and 2000 came along increased estimated per capita availability of calories from sweeteners by 74 kcal/d but the TEI rose by 403 kcal/d, indicating that the consumption of other energy rich nutrient had also increased."

And the study presented by Dr Lustig also said: 

"The impact of sugar on diabetes was independent of sedentary behavior and alcohol use, and the effect was modified but not confounded by obesity or overweight."

Leaving behind the questionable quality of the data mentioned earlier, these two quotations need an explanation in a specific context. The Popkin et al study was related to the developing countries. However, as you could see in one of my other articles, in the US the trend of sugar consumption also did not particularly correlate with the ever increasing rise of metabolic diseases for the past 14 years. There certainly was other dietary factor or factors that made this trends worse and it not only could have modified these trends but actually contribute to them. Just because one study did not find a statistical significance it does not mean that a different study performed by different scientists and maybe based on better quality data would not find it. It is quite common that studies do not always come to the same conclusion or they even report the opposite results. 

And that was my point. I did not disprove the findings of this study because I do not see behind all of it. They might have found a true cause-effect relationship, or may not. We cannot be sure for sure because of the limitations associated with it. But my 'feeling' does not let me to leave out the substantially increased fats and oils consumption along the sugar in the world, and the actual drop of sugar consumption in the U.S. while the metabolic diseases, including diabetes, have been increasing. I agree though, that there are groups of people who consume way too much sugar and these are far more likely to develop diabetes. However, their diet is not only rich in sugar but also rich in processed fats and poor in essential nutrients and as Dr Lustig said, this also was not examined in their study. 

After watching one of the older videos from 2012, Dr Lustig announced that there were some sensitive slides not to be published before the main work was published. These were not presented to the audience and were cut off the video. However, from the Q&A at the end of the video at 40:00 minute I have realized that this secret information was related to this econometric study. What I have learned from this video, Dr Lustig announced that they did not have the data available to evaluate the role of glycaemic index of the diet and its possible role in the diabetes development. He also said that the category of roots, pulses, nuts, etc, which have a low glycaemic load did not show a protective effect in the MODEL and that he was surprised, or rather shocked, as he said. Well, perhaps something was wrong with the data? Can we trust the final outcomes then? I leave it up to you. Only future will show the truth. 

At 41:44 minute you can hear the answer on my suggested question earlier in this article: the team had no answer for the remaining 71 or 75% of the causes for diabetes. They simply did not know. He mentioned the genetics... but nothing about dietary fat or the combination of fat with sugar as is for the DONUT or fast food outlets... The remaining three quarters of the 'causes' of type 2 diabetes remained a complete mystery and he tried to make the audience happy with those 25% as pretty good. Something smells here... 

Exercise for weight loss does not work?

At 14:12 you can see the diagram of one meta-analysis which assessed whether there is the body of evidence that physical exercise helps in losing weight. Dr Lustig presented it in a very simple manner - not saying how long the exercise lasted, what the exercise actually was, how many calories equivalent it was to balance a daily energy intake, and so on. I accept that it was not possible as the claim was based on a meta-analysis - pooling together various studies and looking at the evidence in a broad manner. However, all these factors matter in evaluating why something like this works and why not. 

And that is exactly my point here. WHY exercise does not work to curb down the obesity levels? They say there was a small weight loss overall and it was presented as a negligible effect. Nothing was said about whether the people had also their diet altered or not and what their diet consisted of, in general.

Let me put it this way: when you are obese and constantly gaining weight because you consume over 1000 kcal more per day than are your actual requirements for that body size and lifestyle, how long you have to exercise to burn this extra energy plus some more to achieve the weight-loss? 

Here is a brief overview where you can find that if a 68 kg weighing person performs light aerobics, within a half an hour they burn mere 120 kcal. That is not even half of a regular Mars bar in the UK! With the higher body weight the energy expenditure is higher, true, but is it that much? 120 kg heavy person burns around 200 during for the same time doing the same activity. Still not a regular Mars bar, which contains 260 kcal. How much was that burger? Over 1400 kcal.

How long DAILY can you expect an obese person to perform even the light exercise? Not for 3.5 hours to burn off that extra burger calories, would you? And this is every day because they tend to overeat every day, some even double or triple the average energy requirements (extra 2000-4000 kcal) as I have seen in my favorite series Supersize vs. Superskinny. Watch it, it is eye-opening. Available on Youtube.

Any wonder why the exercise showed such a small result? And this is also why the first law of thermodynamics seems not to work here - because in such a high energy intake you cannot expect  a weight loss if the energy output is not exceeding it. Moreover, it needs a substantial amount of time to achieve significant results, which most of such studies do not have. They usually assess the participants over several weeks or a few months at their best. 

Therefore, the things have to be looked at from the whole perspective, not just looking at the data and dismiss this or that saying that exercise does not work. It works, in its own meaning - if people do not lose much weight, they at least do not gain as much as they would without the exercise, am I right?

The little success (half point of BMI as Dr Lustig said) actually has proven that the exercise works, but it has to be accompanied with dietary changes as well. From that slide it is not obvious whether the exercising people also had changed their diet. 

It is generally easy to overeat when the food is so cheap, processed and palatable. Cheap processed food is very energy dense, which means that per 100 grams you can get much more calories form the processed food than from the unprocessed, such as fruits and vegetables. And these calories are not always only sugar, most of the time there is more fat calories than sugar calories. Add little salt and you have got a deadly trio that has the potential to make people addicted to this particular diet. 

Moreover, the exercise has been found to be very effective in decreasing the risk of metabolic diseases such as type 2 diabetes. In fact, the exercise alone was found to be even more effective than the dietary changes alone. Surprised? I am not. It has its rationale based on our physiology. It is very simple: when you over consume, you store the energy not only in the fat, but also in the muscles and liver up to a certain point as their storage capacity is limited, unlike for the fat deposits. 

Especially the muscles are responsible for the most of the insulin mediated glucose uptake in the body. When you overeat and have a sedentary lifestyle or remain bed bound for several days, they are kept in the 'full of energy' state during the day and cannot take in any more. In excess, the glucose, instead of refueling the muscles, keeps circulating in the body and the body keeps producing more insulin to fit it somewhere as it should not stay in the blood in high concentrations. That leads to hyperinsulinemia. 

Humans have quite a low capacity for the de-novo lipogenesis (DNL) as you could see elsewhere. There are other processes that happen in such a hypercaloric state but this is the main mechanism. Once the person starts exercising, the muscles burn the energy they have and start taking in more again which results in the drop of a high blood glucose and also blood lipids. And since high levels of insulin are not needed anymore, insulin drops down also. That's it!

We, as a species, have evolved being physically active and that is the need of our physiology today, too. Stop being active and the consequences come. Plug the hole in the sink and it will soon overflow. As long as one or two days of being bed bound with excessive eating can lead to the changes in our biochemistry indicating a pre-diabetic state. Keep doing the exercise while overeating and you will just keep gaining weight while you will most likely remain metabolically healthy for a pretty long time. Just please do not take this as my approval to overeat, OK? Healthy weight also matters. 

And finally: look at the diagram above again. The plot contains the results of different studies. Some worked, others did not, when examining the effectiveness of exercise on the weight management. It was only the overall figure of pooling all these results together that Dr Lustig presented as the small and negligible difference. At least the three studies (towards the left from the vertical line expressing that mean results) showed quite a success, did they not? I would have to look at each of them individually to give you a full report what made them show the effect and why other studies failed to do so. But even from this you can see that it really depends on the circumstances whether the exercise works or not. The first law of thermodynamics still applies here and the exercise DOES work when the energy output exceeds the energy input in a persistent and more permanent manner.  

One more thing I have noticed when listening the lecture further at the minute 18:55:

Look at the right column Activity. So, if the lowered level of activity has contributed to the obesity epidemics and associated metabolic diseases in children, why suddenly the physical activity does not seem to work, according to Dr Lustig? Yes, he did question this aspect and went for the usual toxic substance (fructose) in our diet after that but it is generally accepted in the scientific community that physical activity does play a role in the weight management and overall health of people and it is usually advised and promoted by the health authorities and implemented into the government policies, too. Dr Lustig provided no sufficient evidence that the physical activity is negligible or does not work in maintaining a healthy body weight, except of the meta-analysis study mentioned earlier. 

To be on a neutral side I must say that other studies also concluded that the exercise has little impact on weight loss and the change in the diet produces a higher effect, but this was only because of the insufficient balance of the calories I have discussed above. It is more effective not to eat that chocolate cake than trying to burn it off.

I know it from myself: I have been maintaining a lower body weight for some time now, with tiny fluctuations in one kilo up or down. And I know that when my physical activity suddenly increases for a couple of days while the diet remains the same and balanced, my body analyzing scales notice this with a couple of dekagrams and also estimate a lower percentage of body fat in my legs while increasing the percentage of water and muscles. I need no further evidence that the exercise works. I assess my body composition quite regularly, I maintain a record and do it at pretty constant conditions. The measurements were also consistent all the time. 

And here I come to the last point of this article: there is a difference between maintaining a healthy body weight and reducing the body weight of obese people. These two premises are quite different, because when you are of a healthy weight, it requires less effort from you to exercise and you also need to exercise less to keep the energy in balance. For obese people this is particularly difficult to do on a regular basis and the drop-off rate is also very high, which contributes to the failure of such programs. What may be a light aerobic for a fit person, for an obese person it can become quite a burden after 5 or 10 minutes. Now imagine them doing this for an hour to merely burn the single Mars bar... 

But, as one large supermarket chain advertises: 'Every little helps', the burned 120 or 200 kcal means they were not deposited in the fat stores and the muscles are now ready to take more glucose and more fat from the blood stream. Remember Dr Lustig saying that obesity is not a problem and that 20% of obese people are metabolically healthy? Well, 80% are not and physical activity has a huge potential in helping them out of this doom. He also admitted this in another video at 1:18:05 time that he has been struggling with his high body weight and the diet, but that the constant physical exercise helps him to reduce the abdominal fat deposits.