Low-fat diets are just as ineffective as many other diets for achieving long-term weight loss

Another diet bites the dust after research shows a low-fat regime is not better for long-term weight loss.

"There is no good evidence for recommending low-fat diets," says Dr Deirdre Tobias, lead author of a study published in The Lancet Diabetes & Endocrinology journal.

The diets don't lead to greater weight loss in the long term compared to higher-fat diets, such as low-carbohydrate or Mediterranean programs, of similar intensity.

Dr Tobias is from Harvard Medical School in Boston.

The analysis of 53 studies involving 68,128 adults showed no difference in the average weight loss between reduced-fat diets and higher-fat diets, said to have been followed for at least a year.

"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," she said.

"But our robust evidence clearly suggests otherwise."

Reduced-fat diets only led to greater weight loss when compared to no diet at all but they did result in less weight loss compared with low-carb interventions.

However Kevin Hall from the National Institute of Diabetes and Digestive and Kidney Diseases in the US, said the one kilo difference was "clinically meaningless".

He noted that regardless of the type of diet prescribed, the study showed long-term weight loss was "unimpressive".

"What seems to be clear is that long-term diet adherence is abysmal, irrespective of whether low-fat or other diets ... are prescribed."

Australian experts said the findings are consistent with evidence underpinning the nation's obesity, dietary and weight management guidelines which do not promote low-fat diets.

"They promote eating a wide variety of healthy foods, including healthy (unsaturated) fats," said Professor Amanda Lee from the Queensland University of Technology.

They also recommend limiting intake of alcohol and of junk foods with high levels of saturated fat, salt and sugar.