Book notes: The Diet Myth

A fascinating book by Professor Tim Spector, of King’s College, London debunks many of the myths about dieting, including the received wisdom that the best way to lose weight and live healthily is simply to consume fewer calories and exercise more – the implication of this being that “if you can’t manage this, you simply lack willpower”. That is far too simple. The fact that waistlines continue to expand by an inch every decade in the UK and obesity is increasing all round the world requires more complicated explanations. (Obesity rates have trebled in the United States, China and India over the last three decades).

Why is the traditional advice not always useful? On cutting calories:

Our bodies simply seem to adapt to the new reduced calorie intake and do what they are programmed by evolution do. It appears that the dull monotony of mob most exclusion diets is overridden by the body’s impulse to hold on to our fat stores. Once someone has been obese for a while, a whole series of biological changes transpire to maintain or increase their fat storage and the brain’s reward mechanisms for food. That is why most diets fail.

And on exercising the story is similar:

The reason why millions of us don’t lose weight exercising is that our bodies compensate. The body is programmed to stop us losing weight via fat and we have to expend five times more energy to get rid of fat than muscle…..When people have successfully lost weight in three to six months through diet can exercise work to keep it off? The short answer is no. In a recent meta analysis of seven studies exploring exercise alone, or exercise plus diet, versus diet alone, exercise failed dramatically to have any effect over placebo or control interventions. Nearly everyone refined weight and without dietary restriction exercise had little influence.

Prof Spector’s research suggests that two other factors are just as important n determining weight loss and gain – your genetic makeup and the millions of microbes that live in your digestive system. You can’t do much about the former, but what you need in the latter case is as much diversity in your microbe population as you can get. One unpleasant way to do this is to have a “stool transplant” (no, it doesn’t appeal to me either). But there are others:

People who are basically fit but want to be healthier can achieve this in a fairly straightforward way by helping their microbes in the ways I’ve suggested. Try to eat a greater variety of foods, particularly fruits, olive oil, nuts, vegetables and pluses plus fibre and polyphemus.. Avoid processed foods, anything that claims to be a special low-fat or light product or has too many ingredients,, and reduce your meat intake. Eat traditional cheese and full-fat yoghurt, avoiding synthetic varieties. Try adding more variety of fermented foods to your diet like refit, fermented cabbage or soybsed foods.

I like the concept that our ancestors ate in very irregular and seasonal ways, so intermittent fasting for giving up meat for months at a time or skipping some meals seems sensible to enhance your perception of variety. Throughout the year try to eat fruits and vegetables that are in season so as to increase the diversity of the foods you consume. Also, cutting back on liquid calories, such as sugar in juices and other drinks, as well as calories in cases and snacks, is sensible, as is avoiding artificial sweeteners as a regular alternative.

There is plenty more detail on the different types of food we eat (fats, fibre, protein etc) in the book, together with a reminder that “consume by” and “best before” labels on supermarket food are worse than useless, a gift to the food industry that also contributes mightily to the scandalous amounts of perfectly edible food that goes to waste every day. OK, you probably all know most of this already, butĀ The Diet Myth is a useful corrective to the ongoing special pleading of the diet industry.