San José, Costa Rica, since 1956

The ups and downs of yo-yo dieting

Julie Godfrey

Julie Godfrey

Yo-yo dieting is better than doing nothing at all to control your weight, according to a recent study conducted on mice at Ohio University in the United States.

The study switched mice between low-fat and high-fat diets every four weeks over two years, comparing their health markers with two control groups, one fed just the high-fat diet and the other only the low-fat diet. Significantly, the yo-yo-dieting mice lived almost as long as the low-fat-diet mice and about 25 percent longer than the high-fat-diet group. Weight and glucose levels of the yo-yo dieters varied according to phase of diet; during the high-fat phase, weight increased, as did blood glucose levels, but both returned to normal during the low-fat dieting phases.

Not mentioned was whether the dieting mice put on even more weight during their high-fat phases – a typical reaction in humans when yo-yo dieting. Weight comes off quickly, but when dieting stops, the original weight and more creeps back on. This is because when calories are suddenly and significantly reduced, the body thinks it is in starvation mode and reacts by slowing down metabolism to conserve energy. When calorie intake rises again, the body no longer needs the extra energy as it has adjusted its metabolism accordingly; instead, it will enthusiastically store those extra calories as fat.

The conventional strategy of reducing calories and increasing exercise (which boosts metabolism) remains the most effective path to long-term weight reduction and maintenance. While a quick dip in pounds can be encouraging, try to look at weight loss as an exercise in time management. Think of a weight goal you want to achieve in six months’ time. Then, identify and prioritize six unhelpful eating and lifestyle habits you know you should change in order to shift that weight, and substitute one new good habit in place of a bad one each month. For example, in month one, you could swap soft drinks for water; in month two, take a 20-minute walk each day; in month three, take a healthy lunch to work instead of buying fast food, and so on. Before you know it, the six months are up, and, if you stuck to the gradual plan, you should have dropped an encouraging number of pounds almost without realizing it.

If you feel the need for a diet per se, try the low-glycemic index/glycemic load diet, which restricts processed and refined carbohydrates in favor of lower-fat proteins and moderate amounts of complex carbohydrates, such as whole grains. Some fruits and (nonstarchy) vegetables can be eaten in abundance.

Yo-yo dieting is not a strategy we recommend, and studies need to be done with humans to validate the results in mice. However, if you consistently battle with your weight, the preliminary message is that it could be better to have lost and regained than never to have lost at all.

Julie Godfrey, B.Sc. (Hons), is a nutritional therapy practitioner and full member of the British Association of Applied Nutrition and Nutritional Therapy (BANT).

Comments are closed.