WHAT IS THE BEST DIET, ACCORDING TO SCIENCE?

When it comes down to it, the science of dieting is simple: eat less. You can do it with a low-fat diet (like the raw food diet), or a low- carb diet (like the Atkins or paleo diet). But the problem with diets is not so much losing weight, but finding a way to do it that is effective, safe, fits in with your lifestyle, and is sustainable so that your weight doesn’t rocket up again.

Diet academics (as opposed to product pushers) avoid prescriptive advice because different diets fit different people’s lifestyles and personalities. But recent research indicates that one particular group of diets is most effective for the greatest number of people. These are the supervised diet programmes, like the Cambridge Weight Plan, LighterLife and Optifast diets, consisting entirely of pre-prepared snack bars, shakes and other food products. You might assume these fast-acting diets would be condemned by scientists as drastic, unhealthy and gimmicky. Yet research is finding that these very low- calorie diets, also known as total food replacement diets, are effective and safe if applied correctly. A major analysis of trials last year, headed by Birmingham University’s Centre for Obesity Research, showed that these diets brought an average weight loss of 10kg after 12 months. This compares with research showing that behavioural programmes (focused on changing eating habits and exercising), such as Slimming World and Weight Watchers, bring a weight loss of 4kg after one year.

Jebb explains that, although research indicates that all dieters gain weight afterwards (no matter which regime you embark on), the more weight you lose the longer you stay beneath the ‘obese and unhealthy’ bar. “The research shows that the food replacement programmes which provide weekly or monthly behavioural support are associated with the best long-term success,” she says.

And though food replacement diets may look extreme, they do contain a balance of nutrients that some do-ityourself diets – for example, the milk diet or the lemonade diet – might not.

“Food replacement diets are easy, and if you want to lose weight, why not do it quickly? What’s not to like?” Jebb says.

Verdict: Try a supervised diet programme to safely shed excess weight.