Diets have to be the least successful health campaigns in history. In the past 30 years bookshelves have become stuffed with how to guides, governments spend millions on task forces and the media are stuffed with warnings and advice. In that time the percentage of people in Britain classified as obese has risen ten fold.
But while as health promotion it’s been a disaster, as a money making exercise it’s been nothing short of brilliant. The food industry has found ever more ingenious ways to make as cheaply as possible nutritionally rubbish food which they sell as expensively as they can. Then they flog diet options to counter the effects and the media gorge themselves on an endless supply of health and diet stories.
Zoë Harcombe starts by wondering why it is that humans, whose bodies evolved to regulate themselves, should be experiencing a weight crisis. It is questionable whether we’re really not exercising enough when you consider how many people you know who run or play sport. It seems odd when the average daily calorie intake is lower than a generation ago.
In a series of rigorously sourced chapters she pulls apart many of the key tenets in the diet business. The science behind them is contradictory and often based on mantras about which we know little. A good example is the formula that 1lb fat contains 3,500 calories, so to lose 1lb a week you need a deficit of 500 calories a day. This is a diet shibboleth yet the Department of Health, one of its adherents, told Harcombe it didn’t know the rationale behind it and the British Dietetic Association refused to say if it had any evidence for it. Harcombe painstakingly dissects statements such as “people are fat because they eat too much and exercise too little”.