Switching diets after 6-months does not result in renewed weight loss: a secondary analysis of a 12-month crossover randomized trial.

Abstract

Weight change trajectory from diet and lifestyle interventions typically involves rapid weight loss followed by a weight plateau after approximately 6months. Changing from one weight-loss diet to another at the time of the plateau could instigate renewed weight loss. Therefore, our secondary analysis aimed to assess trajectory of weight loss in a 12-month, randomized, cross-over study. Forty-two adults were randomized to eat a healthy low-fat or healthy low-carbohydrate diet for 6months then switched to the opposite diet for an additional 6months. Regardless of diet assignment, participants experienced rapid initial weight loss, which slowed between 3 to 6months. After switching diets at 6months, weight modestly decreased until 9months, but at a rate slower than the initial 3months and slower than the rate from 3 to 6months. This suggests that the weight loss plateau typically seen at 6months is physiological and cannot be overcome by simply switching to a different weight-loss diet.