Gradual weight loss is no better than rapid weight loss for long term weight control, study finds

A new study has challenged the common belief that losing weight gradually is better in the long term than rapid weight loss. The findings showed that regaining weight was just as common regardless of the speed of weight loss.

Over the past decade dietary experts have recommended gradual weight loss for obese people—probably because they believe that the longer people spend losing weight, the more likely they are to establish healthier eating habits.

To test this hypothesis Australian researchers randomised 204 obese adults (body mass index 30-45 kg/m²) to either a 12 week rapid weight loss programme on a very low calorie diet (450-800 kcal/day) or a 36 week gradual weight loss programme, which reduced participants’ daily energy intake by about 500 kcal.1 Participants who lost more than 12.5% of their body weight were then placed on a weight maintenance diet for three years.

The results, published in Lancet Diabetes and Endocrinology, showed that the participants who lost weight more quickly were more likely to achieve their target weight loss: 81% of participants on the rapid weight loss programme lost at least 12.5% of their body weight, compared with only 50% in the gradual weight loss group.

At the end of the three year follow-up period the researchers found that most of the participants had regained most of the weight. Those in the gradual weight loss group had regained an average of 10.4 kg, 71.2% of the weight that they had lost (95% confidence interval 58.1 to 84.3), while those who had rapidly lost weight regained 10.3 kg (70.5% (57.8 to 83.2)).

The biggest limitation of the study was that it excluded people who smoked, had diabetes, used weight altering drugs, or were severely obese—which made the findings difficult to generalise to most people who seek medical help to lose weight, said the researchers.

In a statement Katrina Purcell, dietitian at the University of Melbourne and the first author on the paper, said, “Across the world, guidelines recommend gradual weight loss for the treatment of obesity, reflecting the widely held belief that fast weight loss is more quickly regained. However, our results show that achieving a weight loss target of 12.5% is more likely, and drop-out is lower, if losing weight is done quickly.”

In a commentary on the study Corby Martin and Kishore Gadde, of Pennington Biomedical Research Center in Baton Rouge, United States, concluded, “The study . . . indicates that for weight loss, a slow and steady approach does not win the race, and the myth that rapid weight loss is associated with rapid weight regain is no more true than Aesop’s fable.

“Clinicians should bear in mind that different weight loss approaches might be suitable for different patients in the management of clinical obesity, and that efforts to curb the speed of initial weight loss might hinder their ultimate weight loss success.”2

In a statement through the Science Media Centre, Naveed Sattar, professor of metabolic medicine at the University of Glasgow, said, “This appears a well done study, but the extent to which it really represents ‘gradual’ weight loss in the control arm of the study is unclear, since losing around 15% [of body weight] by eight months would still be considered a rapid weight loss in some minds. For me, gradual weight loss would be a loss of around 3% at three months before a period of weight maintenance—and then individuals can revert to weight loss if so desired.

“It may be best for the majority of individuals to lose weight even more slowly than in this study, and more work is needed in this space to test this.”

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