Low-Fat Diets Don't Work, Not In The Long Run

Renowned research journal The Lancet has confirmed what many have been preaching for years: low fat diets won’t help you lose weight.

According to the study, which analysed the diets of more than 68,000 adults, low-fat diets don’t lead to greater weight loss in the long run compared to higher-fat diets, like the Mediterranean diet.

The study’s lead author, Dr Deidre Tobias, said there is no good evidence to support recommending low-fat diets to lose weight.

“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,” Dr Tobias said.

Tobias and colleagues conducted a systematic review and meta-analysis of all randomised trials comparing the effectiveness of low-fat diets to other diets, including no diet, at improving long-term weight loss (over at least 1 year) in non-pregnant adults up to the end of July 2014.

They took into account the intensity of the diets which ranged from just pamphlets or instructions at the beginning of the programme, to intensive multi-component programmes including counselling sessions, meetings with dieticians, food diaries, and cooking lessons.

Analysis of 53 studies involving 68,128 adults revealed 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 (weighted mean difference 1.15 kg/2.5 lbs).

Similarly, when just considering trials without a weight loss goal (e.g, those assessing lipids or cancer endpoints), participants following a reduced-fat diet lost similar amounts of weight on average compared to those on other diets.

According to Dr Tobias, “The science does not support low-fat diets as the optimal long-term weight loss strategy”.

“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.”

Dr Tobias reminded us that long-term adherence to a certain diet is critical so its success, and that we should take into account any other long-term health effects of our diet decisions.