low-fat diet won't make you slimmer in long term: Study

Having low-fat diet does not lead to greater weight loss in the long term compared to higher-fat diets of similar intensity, says a lancet study.

The results are based on analysis of past studies involving more than 68,000 adults.

"Behind current dietary advice to cut out the fat, which contains more than twice the calories per gram of carbohydrates and protein, the thinking is that simply reducing fat intake will naturally lead to weight loss. But our robust evidence clearly suggests otherwise,” said lead author Deirdre Tobias from Harvard Medical School, Boston, US.

Tobias and colleagues did a systematic review and analysis of all randomised trials comparing the effectiveness of low-fat diets to other diets, including no diet, at improving long-term weight loss (at least one year) in non-pregnant adults up to the end of July 2014. 

Analysis of 53 studies involving 68,128 adults showed no difference in the average weight loss between reduced-fat diets and higher-fat diets. 

Indeed, reduced-fat diets only led to greater weight loss when compared with no diet at all, and resulted in less weight loss compared with low-carbohydrate interventions, although differences in weight change were small.

"The science does not support low-fat diets as the optimal long-term weight loss strategy,” Tobias noted.

"To effectively address the obesity epidemic, we will need more research to identify better approaches for long-term weight loss and weight maintenance, including the need to look beyond differences in macronutrient composition--the proportion of calories that come from fat, carbohydrate, and protein,” Tobias explained.

The study was published in the journal The lancet Diabetes & Endocrinology.