Why extreme diets don't work

How to avoid yo-yo dieting

It's that time of year again. Suddenly June, with its call for shorter hemlines, no sleeves and flesh-bearing beachwear, is looming and the need to shift weight fast is on us. Times columnist Robert Crampton had his own “bikini” moment a few weeks ago and resolved to lose 20lb in only four weeks. He has been offered plenty of quick weight-loss tips from concerned Times Health Club members.

The “yo-yo” syndrome

But is it safe for Robert and other pre-summer dieters to shed weight quickly with near-starvation rations, especially if we pile it all back on again rapidly in that classic yo-yo pattern? Andrew Prentice, Professor of International Nutrition at the London School of Tropical Medicine and Hygiene and an expert on obesity, says that from a metabolic point of view it is not a problem: “While it is true that when we diet our metabolic rate [the rate at which we burn energy] goes down, it simply drops to a level which is appropriate to our new weight. If you were to put the lost weight back on again, it would bounce back up...human metabolism is designed to yo-yo.” That said, some “starvation rations” are nutritionally better for you than others.

The cabbage soup diet, for example, is one of the worst and leaves you feeling so lethargic and bored that you go mad once any proper food is on offer again and the pounds pile back on with alarming speed.

Special meal-replacement diets such as the Cambridge Diet and Lighter Life consist of shakes, bars and soups, which have been fortified to provide all the vitamins, minerals and protein you need, while keeping calories to well under 1,000 a day. These are better because they give rapid weight loss results while leaving you feeling pretty healthy, although, again, you may struggle to avoid regaining weight once you return to the diversity of “real” food.

The high-protein diets that Robert has been advised to follow by some Times Health Club members give fast results, but they risk upping your intake of saturated fats to a dangerous level, and if your kidneys are not in tip-top condition, excess protein can strain these two small organs and cause permanent damage.

Seven key tips for keeping weight off

1. Find a way of losing weight that you enjoy and is within your budget.

2. Catch “slips” before they turn into larger weight regains.

3. Maintain a consistent eating pattern across weekdays and weekends.

4. Monitor your weight regularly.

5. Eat breakfast every day.

6. Do some kind of physical activity.

7. Eat a low-calorie, low-fat diet.