If you have any interest at all in diet, obesity, public health, diabetes, epidemiology, your own health or that of other people, you will probably be aware that sugar, not fat, is now considered the devil's food. Dr Robert Lustig's book is Fat Chance: The Hidden Truth About Sugar, Obesity and Disease http://www.amazon.com/Fat-Chance-Beating-Against-Processed/dp/0142180432, Lustig has spent the past 16 years treating childhood obesity. His meta-analysis of the cutting-edge research on large-cohort studies of what sugar does to populations across the world, alongside his own clinical observations, has him credited with starting the war on sugar. When it reaches the enemy status of tobacco, it will be because of Lustig. Lustig argues that sugar creates an appetite for itself by a determinable hormonal mechanism – a cycle, he says, that you could no more break with willpower than you could stop feeling thirsty through sheer strength of character. He argues that the hormone related to stress, cortisol, is partly to blame. "When cortisol floods the bloodstream, it raises blood pressure; increases the blood glucose level, which can precipitate diabetes. Human research shows that cortisol specifically increases caloric intake of 'comfort foods'." High cortisol levels during sleep, for instance, interfere with restfulness, and increase the hunger hormone ghrelin the next day. This differs from person to person, but deliciousness of doughnuts is all too familiar when you haven't slept well. "The problem with obesity is that the brain is not seeing the excess weight." 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 flip switch is your leptin level (the hormone that regulates your body fat) but too much insulin in your system blocks the leptin signal. Telling people to simply lose weight, "is physiologically impossible and it's clinically dangerous. It's a goal that's not achievable. Biochemistry drives behaviour. 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." To extend that, you could tell people with diabetes not to drink water, and 3% of them might succeed – the outliers. But that wouldn't help the other 97% just as losing the weight doesn't, long-term, solve the metabolic syndrome – the addiction to sugar – of which obesity is symptomatic. Many studies have suggested that diets tend to work for two months, some for as long as six. "That's what the data show. And then everybody's weight comes roaring back." During his own time working night shifts, Lustig gained 3st, which he never lost and now uses exuberantly to make two points. The first is that weight is extremely hard to lose, and the second –"I'm not a fitness guru, I'm 45lbs overweight" He doesn't want everybody to be perfect: he's just a guy who doesn't want to surrender civilisation to diseases caused by industry. This is an industry problem; the obesity epidemic began in 1980. Back then, nobody knew about leptin. And nobody knew about insulin resistance until 1984. "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." Approximately 80% of the packaged foods you can buy in the US have added calorific sweeteners. Daily fructose consumption has doubled in the past 30 years in the US, a pattern also observable in the UK, Canada, Malaysia, India, right across the developed and developing world. World sugar consumption has tripled in the past 50 years, while the population has only doubled; it makes sense of the obesity pandemic. Adding sugar to everyday food has become as much about the industry prolonging the shelf life as it has about palatability; if you're shopping from corner shops, you're likely to be eating unnecessary sugar in pretty well everything. It is difficult to remain healthy in these conditions. "The problem isn't a knowledge deficit; there isn't a fat person on Earth who doesn't know vegetables are good for you. !, personally, don't have a lot of hope that those things will turn things around. This is a substance of abuse; education has never solved substance abuse. . So you need two things, you need personal intervention and you need societal intervention - rehab and laws. Education would come in with rehab. But we need laws." "We have to do something about it, or there will be no healthcare. In fact, there will be no society. Are you ready for that? That's what's gonna happen. It's just not OK. There will be no money left for anything else."

• published: 26 Dec 2015
• views: 249