No long-term difference after rapid or gradual weight loss

Slow and steady weight loss does not reduce the amount or rate of weight regain compared with losing weight quickly, according to research 'The effect of rate of weight loss on long-term weight management: a randomised controlled trial', published in The Lancet Diabetes & Endocrinology.

"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,” said Katrina Purcell, dietician and the first author on the paper from the University of Melbourne, Australia. “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."

The study, led by Professor Joseph Proietto, Sir Edward Dunlop Professor of Medicine at the University of Melbourne and Head of the Weight Control Clinic at Austin Health in Australia, set out to examine whether losing weight at a slow initial rate, as recommended by current guidelines worldwide, results in larger long-term weight reduction and less weight regain than losing weight at a faster initial rate in obese individuals.

The Australian trial included 200 obese adults (BMI30–45) who were randomly assigned to either a 12-week rapid weight loss (RWL) programme on a very-low-calorie diet (450–800 kcal/day) or a 36-week gradual weight-loss (GWL) programme. The GWL programme reduced participants' energy intake by approximately 500 kcal/day in line with current dietary weight loss guidelines. Participants who lost more than 12.5% of their bodyweight were then placed on a weight maintenance diet for three years.

They reported that participants who lost weight faster were more likely to achieve target weight loss with 81% of participants in the RWL group losing  ≥12.5% of their bodyweight versus just 50% in the GWL group.

The researchers also found that the initial rate of weight loss did not affect the amount or rate of weight regain in these patients who entered the subsequent weight maintenance period, as similar amounts of weight were regained after three years by participants who had lost weight on either diet programme. Weight regain was around 71% in both groups after three years.

The authors suggest a number of possible explanations for their findings including that the limited carbohydrate intake of very-low-calorie diets might promote greater satiety, and less food intake by inducing ketosis. In addition, losing weight quickly may also motivate participants to persist with their diet and achieve better results.