After years of being told that fat consumption is a dietary no-no, the latest research indicates that sugar, not fat, is the real demon in our diets.
Fat was labelled the bad guy years ago in what was essentially a political decision which pandered to the immense weight of the sugar industry.
Dr. Robert Lustig exposes this truth in a new book entitled Fat Chance: The Hidden Truth About Sugar, Obesity and Disease, in which he compiles the findings of sixteen years of research into childhood obesity. By his own admission, Dr. Lustig is now at war with what he believes to be one of the most insidious and deadly enemies on the planet: sugar. He says he will not be content until "the white stuff" is considered in the same harmful terms as alcohol or tobacco.
"Politicians have to come in and reset the playing field, as they have with any substance that is toxic and abused, ubiquitous and with negative consequence for society," he says. "Alcohol, cigarettes, cocaine. We don’t have to ban any of them. We don’t have to ban sugar. But the food industry cannot be given carte blanche. They’re allowed to make money, but they’re not allowed to make money by making people sick."
Lustig’s research has determined that sugar affects appetite by creating a powerful hormonal cycle that would as difficult to resist as trying to ignore our physiological urge to drink when we are thirsty. The stress hormone, cortisol, is one of the culprits in the cycle:
"When cortisol floods the bloodstream, it raises blood pressure; increases the blood glucose level, which can precipitate diabetes", explains Lustig. Human research shows that cortisol specifically increases caloric intake of ‘comfort foods’." For example, elevated cortisol levels during sleep interfere with restfulness, and increase the hunger hormone ghrelin the next day.
"The problem with obesity is that the brain is not seeing the excess weight," continues Dr. Lustig, who is a pediatric endocrinologist at the University of California, San Francisco (UCSF) where he is a Professor of Clinical Pediatrics. "The brain can’t see it because appetite is determined by a binary system. You’re either in anorexigenesis – "I’m not hungry and I can burn energy" – or you’re in orexigenesis – "I’m hungry and I want to store energy."
The deciding factor is your leptin level (the hormone that regulates your body fat), and excess insulin in your system blocks the leptin signal with the result that you feel constantly hungry.
This makes it incredibly difficult for some obese people to lose weight. Simply urging them to do so is, according to Dr. Lustig," physiologically impossible and it’s clinically dangerous. It’s a goal that’s not achievable."
In his book he explains that the behavior of the overweight individual is often driven by physiological urges that shape their psychological responses: "Biochemistry drives behaviour," he states." You see a patient who drinks 10 gallons of water a day and urinates 10 gallons of water a day. What is wrong with him? Could he have a behavioural disorder and be a psychogenic water drinker? Could be. Much more likely he has diabetes."
Lustig himself is 45lbs overweight, and so speaks from personal experience. He knows that most diets do not work and that the weight returns once the programme is over, but he maintains that the reason that most dieters lose the battle is metabolic syndrome, or sugar addiction.
But the problem is going to be a difficult one to combat as the food industry revolves heavily around the production of and use of sugar.
"Sugar causes diseases: unrelated to their calories and unrelated to the attendant weight gain. It’s an independent primary-risk factor. Now, there will be food-industry people who deny it until the day they die, because their livelihood depends on it," argues Lustig.
Lustig explains how the sugar content in our foods increased in the wake of the low-fat crusade:
"What they knew was, when they took the fat out they had to put the sugar in, and when they did that, people bought more. And when they added more, people bought more, and so they kept on doing it. And that’s how we got up to current levels of consumption."
Education isn’t necessarily the answer, says Lustig, as most people are well aware that sugar is not a healthy food: "I, personally, don’t have a lot of hope that those things will turn things around. Education has not solved any substance of abuse. This is a substance of abuse. So you need two things, you need personal intervention and you need societal intervention. Rehab and laws, rehab and laws. Education would come in with rehab. But we need laws."
Sugar consumption is so heavily interwoven into Western diets and lifestyles that it would take a radical change to re-habituate the population and change the economics of the food industry. But before you denounce sugar and replace it with sugar-substitutes and sweeteners, read on. A study published this week in the journal Nature suggests that high doses of artificial sweeteners such as saccharin, sucralose and aspartame can negatively affect our populations of healthy gut bacteria, and could be contributing to the problems they were designed to combat.
Experiments conducted in mice and in some humans indicate that changes in gut microbiota can ultimately affect sugar metabolism and cause weight gain, though further studies are needed to consolidate these results.
"We are by no means prepared to make recommendations about the use and dose of sweeteners, but these results should prompt additional study and debate on the massive use of artificial sweeteners," said Eran Segal a computational biologist at the Weizmann Institute of Science in Israel and a senior author of the paper.
Artificial sweeteners do not contain any calories as they are not digested by the body, but they still have physiological effects as they pass through our digestive systems. The latest study identified that one of the most concerning of these is the effect of sweeteners on glucose metabolism.
A series of experiments on mice illustrated that glucose intolerance began to occur in those mice who had been fed saccharine, sucralose or aspartame, a result that was echoed in subsequent tests.
So sweeteners can potentially have the same effect as excess sugar intake, causing insulin resistance and eventually obesity. The study authors now consider them to be part of the diet and lifestyle factors that form part of the obesity epidemic and "diseases of the Western lifestyle" like diabetes, obesity and food allergies, none of which were the accepted norm fifty years ago.
"Our microbiota have co-evolved with us over millennia, but they are not evolved for a McDonald’s diet, or consistent antibiotic use,” she said. “Now, I would say we could add artificial sweeteners to this list."
Whether sweeteners are still a preferable option to sugar is still not clear, but it seems that a return to the simpler and less-processed foods of our past must surely be a route to resolution. In many cases, if it comes in a packet, then the chances are that either sugar or some form of artificial additive will have been added to our foods; Nature, it seems, has always known best.