Australasian Science: Australia's authority on science since 1938

Slow and Steady Does Not Win the Weight Loss Race

Gradual weight loss does not reduce the amount or rate of weight regain compared with losing weight quickly, according to research published in The Lancet Diabetes & Endocrinology.

In fact, the study found that substantial weight loss is more likely to be achieved if undertaken rapidly. “This randomised study highlights the urgent need for committees that develop clinical guidelines for the management of obesity to change their advice,” said Prof Joseph Proietto of The University of Melbourne and Austin Health.

The trial included 200 obese adults who were randomly assigned to either a 12-week rapid weight loss program (average weight loss 1.5 kg/week) on a very low-calorie diet of 450–800 Cal/day, or a 36-week gradual weight loss program (0.5 kg/week) based on current dietary recommendations.

“Global guidelines recommend gradual weight loss for the treatment of obesity, reflecting the widely-held belief that fast weight loss is more quickly regained,” said study co-author and dietitian Katrina Purcell. “However, our results show that an obese person is more likely to achieve a weight loss target of 12.5% weight loss, and less likely to drop out of their weight loss program, if losing weight is done quickly,” she said.

The researchers found that the initial rate of weight loss did not affect the amount or rate of weight regain. Similar amounts of weight were regained within 3 years by participants on both diet programs who completed both phases of the study (around 71% in both groups).

The authors suggested a number of possible explanations for their findings. For example, the limited carbohydrate intake of low-calorie diets promotes greater satiety and less food intake by inducing the production of hunger suppressants called ketones. Losing weight quickly may also motivate participants to stick to the diet.