Have we had presented the whole picture or was there something missing?

At about 38:30 Dr Lustig says that liver is the only site for energy metabolism. He presented a slide showing: 

During that time, as he did not want to appear a fructocentric, he pointed out at these four food substrates that drive the metabolic disease by overloading the mitochondria in the liver and producing fat. Well, where is glucose? Is glucose not an energy molecule? Is it not metabolized by the liver? And, more importantly: is it not converted to fat when in excess? Of course it is. But Dr Lustig has some sort of sympathy for glucose and blaiming only fructose for everything, with the recent addition of these three substrates on top of it. The only difference is that glucose metabolism is regulated by insulin - in a secondary manner, it does not need insulin to enter the liver. 

Yes, I agree that about 80% of glucose is metabolized in the rest of the body, but the truth also is that the isotopes of labelled fructose were found in breath in higher concentrations than of labelled glucose (Chong et al 2007). This means that more fructose was burned straight away than of glucose and other isotope tracer studies confirmed this as well: non-exercising people proportionally burned more fructose while exercising subject burned more glucose, according to the concentrations of recovered labelled carbons (originating from each sugar) in their breath. 

Of course, liver can store unlimited amount of glycogen, from glucose molecules. But this applies mainly on people with genetic disease called glycogen storage disease, as Dr Lustig once said. What he did not say was that the remaining population with functional enzymes for glucose metabolism in the liver do not store excess amount of glycogen when overeating on carbohydrates. And some amount of fructose is also converted to glucose in the liver and even stored as glycogen especially when the glycogen stores are not full. We know it because the isotopic tracer studies have been examining the different fates of labelled fructose as I have discussed earlier and in more detail here. And there is also no pop-off in glycogen from glucose, when the glycogen stores are full. Mitochondria has to deal with excess substrates from either the fructose or glucose (which they have common, interconvertible) and now you already know that it was glucose based carbohydrates the consumption of which has increased much more than of sugar and since 2000, when sugar intake started to decrease in the U.S., the non-fructose carbohydrates stayed the same. 

In this article you can learn how flawed were the conclusions about the de-novo lipogenesis (DNL) of fructose, based on rather indirect assessment methods and how the addition of the same amount of glucose tripled the allegedly measured DNL as a result of fructose intake. 

I am glad Dr Lustig pointed at alcohol in the first slide of this article. He said that little is OK, but too much is not. However, that applies to the fructose, too. In one of my articles I criticized his statement that alcohol is better than sugar because it sends you under the table only once a day. He stated that about 20% of people are addicted to alcohol (1 in 5). Well, have a look at this diagram about the trends in sugar sweetened beverages (SSB) consumption and alcohol consumption among the U.S. adults. *Alcohol is not part of the SSB. The study of Duffy and Popkin (2012) can be found here. 

So, if fructose is an alcohol without the buzz, which allegedly led the metabolic diseases in the U.S. population, how about the alcohol? Even many teenagers have drinking problems. While alcohol is not responsible for the NAFLD, do you think this trend has not affected the population somehow? Just a reminder: from the number of calories within the total SSB fructose forms only about half, which brings it very close to the amount of calories obtained from alcohol. Moreover, fructose is converted to many other compounds (glucose, lactate, glycogen, fat), not just the toxic glyceraldehyde. In comparison, alcohol is temporarily broken down to also a toxic compound - acetaldehyde, but it has not such capacity to be converted to the other compounds as fructose does - except the fats, when consumed in excess. both of them. 

The diagram above is a very crude overview of the trends, and the data may not be absolutely representative of the real situation, but it gives you a hint about what was going on. Many people do not report their guilty pleasures and this is one of the many weaknesses of the dietary surveys. Moreover, this refers to date before 2002 and it would be interesting to see newer trends. But Dr Lustig also likes to present old trends (especially between 1989-1995) as the current ones, so look at the diagram what was happening in those years with alcohol. I also sense some weakness in the data of the NAFLD that it partially could be due to alcohol consumption among youth (or even adults), but because they are under-age their alcohol intake may not have been captured sufficiently and their liver problems only ascribed to other dietary components (sugars, fats). 

Moving on, I particularly appreciate the mention of the corn-fed beef that has a higher profile of branched chain amino acids (and also less healthy fatty acids profile). Is it a news for you that the cheap fast-food has boomed in the western countries in the past decades? What they put into the burgers? Cheap corn fed beef! While the sugar consumption in the U.S. has been decreasing since 2000, the added fats and oils have been increasing, and the consumption of cheap meat as well, while the grass-fed beef and pasture raised chicken meat is rather expensive and not commonly consumed by ordinary people. I am not saying that people consume significantly more meat than they used to decades ago, I am saying that there was a shift from healthy meat to the cheap meat produced on a massive scale today. People also cook less at home today and they rather go to the fast-food and take-away, often serving as cheap ingredients as possible, including the cheap food items such as fries and soft drinks. It is the cocktail of unhealthy foods and drinks is responsible for the poor health of the Western population, not only sugar or fructose alone. 

And, regarding the trans fats: yes their intake has slowly decreased. But what is the real picture? Have you heard about the interesterified fats? Probably not. But you will, in the future. For now, please check what these fats actually are and make your own opinion about this particular statement of nutrient made by Dr Lustig. I think that even he should update his knowledge about the diet, at least within his own country. This article was published in 2007 but his lecture delivered in 2013.

So, I completely agree with his statement: A calorie is not a calorie. Especially after finding out that these interesterified fats actually increase blood sugar (glucose), too. 

This article aimed to show five main things: 

• Alcohol followed the curve with sugary drinks for adults
• There is no glycogen pop-off when the liver or any glycogen stores (muscles) are full, even from glucose. 
• Fructose can also be converted to glucose and glycogen, when the glycogen stores are not full. 
• Since glucose and fructose have common metabolic intermediates, they both in excess can choke mitochondria in any cell in the body, not just the liver. It only happens that fructose has more capacity for this in the liver while the excess of glucose and fat can negatively affect muscle tissue. 
• Although the trans-fats were reduced, they were replaced with equally bad interesterified fats.

The processed food doom continues... 

PS: Every body cell is a site for energy metabolism, not just liver, as Dr Lustig said.