Scientists from Harvard University found that low-fat diet is not the key to solving weight loss problems after embarking on a large-scale study.

Experts have been debating about the effectiveness of low-fat diets in maintaining weight loss over a long period of time. Past and recent studies suggested mixed results and for this reason, the Harvard scientists wanted to know what the truth is, once and for all.

The goal of the new study is to know whether or not low-fat diets can yield greater weight loss compared to usual diets, low-carbohydrate diets or other diets than entail higher fat intake.

The researchers were able to identify 3,517 citations, of which 53 met their inclusion criteria. The total number of participants were 68,128.

After analysis, the authors found that after weight-loss trials, people who consumed low-carbohydrates exhibited major weight loss compared to those who had low-fat diets.

Low-fat diets did not result in weight loss findings that are greater than that of high-fat diets. Higher weight loss for low-fat diets were only noted when compared with a usual diet.

Another notable finding in the weight loss trials is that high-fat diets resulted in more weight loss compared to low-fat diets when the groups had a five percent difference in calories obtained from fat and some discrepancy in serum triglyceride levels at follow-up.

For the non-weight-loss and weight maintenance studies, no low-carbohydrate comparisons were created. The findings of the said analysis showed that low-fat and high-fat diets exhibit similar impacts on weight loss.

The findings of the study suggest that the long-term impact of low-fat diet on weight varies according to the strength of the intervention in the groups. When the diets were compared under similar intensities, the trials lifted low-fat diet above other diets for long-term weight loss.

"There is no good evidence for recommending low-fat diets," said Dr. Deirdre Tobias, the lead author of the study.

"Making good dietary choices does really matter, but it is the type of fat, not the amount, that is most important." Harvard researchers wrote. They added that increased calories from both carbohydrates and fats will result in weight gain, which in turn will heighten the risk of colon cancer, breast cancer and heart disease.

The study was published in the Lancet Diabetes and Endocrinology on Thursday, Oct 29.

Photo: Junya Ogura | Flickr