5 July 2012
For many people, the hardest part of losing weight is keeping the weight off. In fact, research shows only one in 6 overweight people will maintain even 10 per cent of their weight loss long-term. This is partly because after weight loss, energy expenditure (the rate at which you burn calories) decreases, reflecting a slower metabolism.
Now a study has found both low-carbohydrate and low-glycaemic index (GI) diets may be preferable to a low-fat diet for those trying to achieve lasting weight loss.
US researchers evaluated the effects of 3 maintenance diets following weight loss of 10 to 15 per cent in 21 young overweight and obese adults. In the cross-over study, participants consumed a low-fat, low-GI and very low-carbohydrate diet, in random order, for 4 weeks each.
Although the very low-carb diet produced the greatest improvements in metabolism, it led to increased levels of the stress hormone, cortisol, which can lead to insulin resistance and cardiovascular disease. The very low-carb diet also raised levels of C-reactive protein, a marker of inflammation which can also increase the risk of cardiovascular disease.
The low-GI diet had similar metabolic effects to the low-carb diet, keeping energy expenditure (calorie-burning) at a high rate after weight loss, without the negative effects of stress and inflammation.
The low-fat diet caused the greatest decrease in energy expenditure, and was also associated with an unhealthy cholesterol pattern and insulin resistance.
“A strategy to reduce glycaemic load rather than dietary fat may be advantageous for weight-loss maintenance and cardiovascular disease prevention,” the authors concluded, adding that the study challenged the notion that a calorie was a calorie.
“In addition to the benefits noted in this study, we believe that low-glycaemic-index diets are easier to stick to on a day-to-day basis, compared to low-carb and low-fat diets, which many people find limiting,” the authors said.
Last Reviewed: 05 July 2012