Last year, Jo Swinson, a UK business minister, urged magazine editors to end “reckless” promotion of “irresponsible, short-term solutions” to weight loss, and reduce the pressure to conform to “impossible” stereotypes that damage women and men by lowering self-esteem while promoting depression and eating disorders. It was a too late to stop the post-Christmas editions of magazines with cover lines such as “Festive Flab fighter! Lose 7lb in 7 days” and “Flat tum tricks! Try our 3-day diet plan.”
Last week, the World Health Organisation said that it was considering halving the amount of sugar that it recommends people should have in their diet, reducing down to 5% the number of total calories. Let me explain how these two issues are related.
A book released last year tried to explain the truth about diets. Robert Lustig, a American academic who has spent 16 years treating obese children, believes Swinson is right: most diets, even combined with exercise, do not last long. Almost any change of lifestyle works for the first three to six months, he says, but then the weight comes rolling back on leaving the dieter often at a loss to understand why the fat is returning. In fact, says Lustig in his book, Fat Chance, which draws on more than 300 scientific papers, today’s children in the developed world are likely to be the first to die younger than their parents because they are being slowly poisoned by a colossal dietary error a generation ago.
It’s a big claim, based on a simple premise: when the Americans were hunting for the cause of rising rates of heart disease in the 1960s and the 1970s, there were two candidates. One was sugar and the other was dietary fat such as cholesterol. The Americans decided fat was the enemy and by the 1980s a low-fat diet was being recommended in a message that spread worldwide. As the £1.2 trillion industry removed fat from processed products, it raised sugar levels to keep them palatable.
“The goal was to alter our diet for the better,” says Lustig. “Instead, we’ve laid waste to every nutritional hypothesis, lost the public’s trust and killed countless millions.” The fundamental change in our diet that resulted helps to explain why nearly 4,000 American teenagers are now diagnosed annually with type-2 diabetes — once so rare in the young that it was known as “adult” diabetes — and why more than 40% of US death certificates list diabetes, up from 13% two decades ago. The UK, says Lustig, is “right behind”.
A sugary surfeit
Even giving young children organic juice instead of the whole fruit can set them on a path of sugar addiction that leads to diabetes, heart disease, cancer and possibly dementia, he warns. Why? The answer is food is processed differently when it arrives in a sugary surfeit. Fructose, a component of sugar, gets metabolised into fat, including a dangerous form of liver fat. It also activates a liver enzyme, setting off a chain reaction that makes the pancreas release more insulin, the hormone that tells the body to store energy as fat.
The majority of humans, regardless of weight, release twice as much insulin as they did 30 years ago. This extra insulin is believed to block a signal from another hormone, leptin, that tells the brain when you can stop eating. Without this signal, the brain boosts your appetite even if you are full and sends you to the sofa to conserve energy. Something similar happens in a diet of the kind that involves skipping meals.
Your leptin concentrations drop faster than your fat stores. You have not lost any weight yet. But your fat cells tell your brain you are starving, your sympathetic nervous system goes into energy-conservation mode and the vagus nerve, which connects the brain with the abdomen, goes into overdrive, boosting your appetite and ordering the release of insulin to tell your body to store some fat.
Our Second Brain
This raises another important topic, that of our “second brain”. As well as the one in your head, our bodies contain a separate nervous system that comprises an estimated 500 million neurons. Embedded in the wall of the gut, the enteric nervous system (ENS) not only controls digestion, it also plays an important role in our physical and mental well-being. It can work both independently of and in conjunction with the brain in your head, and your ENS helps you sense environmental threats and then influences your response. Your ENS oversees your digestion, and it alerts the brain if it finds dangerous invaders such as bacteria and viruses.
The “feel good” molecule
Our second brain produces a wide range of hormones and around 40 neurotransmitters. This is important as also transmitting signals in your ENS is serotonin, the “feel good” molecule that prevents depression and regulates sleep, body temperature and crucially appetite. Research has shown that nerve signals sent from the gut to the brain do affect our mood. These signals may also explain why fatty foods make us feel good, as when ingested, fatty acids are detected by cell receptors in the gut which send nerve signals to the brain. Why is all this important? Simply because a lot of information about our environment comes from out gut. You are what you eat?
Lustig challenges assumptions by dieticians and doctors that to lose weight we must eat less or exercise more; that a calorie is a calorie, wherever it comes from; and that to shed the pounds we need fewer calories. Not true, he says. The type of food we eat is crucial. Successful diets do exist and have two things in common: they are low in sugar and high in fibre.
Even some popular diets work, although they are flawed. The Atkins diet, a low-carbohydrate regime in which you keep the burger but ditch the bun, is effective for weight loss and improved metabolic health. But it can result in inadequate micronutrients and compromised bone health. The Ornish diet, a low-fat, no-fun diet has been proven not only to promote weight loss but to reverse heart disease. The Mediterranean diet — olive oil, legumes (beans, lentils and peas), fruits, vegetables, unrefined grains, dairy products and eggs, fish and wine in moderation — is excellent, as is the South Beach diet, which keeps insulin low, has plenty of fibre, and avoids added sugar.
But the number of people who can stick to any diet is exceedingly small. So the key is to follow some other simple principles, chief among them shopping on the periphery of the supermarket, where the “real food” is kept, not on the shelves. Real food does not have, or need, a label showing nutritional values. The more labels you read, the more rubbish is in your trolley. Real food takes time to cook but eating it will raise your levels of micronutrients and reduce your fructose. “If you eat real food, your weight will take care of itself, just as it did for the 50,000 years since irrigation and the taming of fire,” says Lustig. “We have no choice but to try to recreate the kind of food supply our grandparents had, before the food processors tainted it.” To make sure, take all your recipes and cut the amount of sugar by a third. And do not forget to exercise.
Traffic light food guide
Lustig uses traffic lights to divide food into three types, a system that might help you with your food choices: greens are “real” foods you can eat as often as you like; yellows are “minimally processed” and can be consumed three to five times a week; and highly processed reds are to be avoided or are for rare occasions.
Green foods include high-fibre cereals such as porridge and shredded wheat. Eggs, milk, grass-fed beef, wild fish, lamb, turkey and free-range chicken can also be eaten without restraint, as can wild or brown rice, whole-grain bread, and home-made salad dressing. Nuts and seeds, fruit and vegetables, plain yoghurt, beans, butter, cheddar cheese — you don’t have to think, just put them in your trolley. Overall, the green foods are high in fibre and low in sugar and “bad” omega-6 and trans fats. They also include tea, coffee and red wine in moderation.
Yellow foods include whole-grain pasta, pitta bread, baked beans, dried fruit and processed meats such as bacon, salami and hamburgers.
The red list has the surprises. Some foods we think of as healthy — bagels, baked potatoes, basmati rice, couscous, fruit juice, rice cakes — are in the danger zone with white bread, pizza and doughnuts.
Don’t compromise your long-term health by believing the fads and trying too hard to lose weight too quickly. By nourishing your body you nourish your second brain, which can all help you feel and look much better, and with an appropriate exercise regime, help you lose weight in a controlled and sustainable way. And after all, that’s what most of us want isn’t it?