“Adherence is crucial,” Johnston told Live Science. Because different people have an easier time sticking to different diets, the ideal diet is the one that the individual can adhere to best, so that they can stay on the diet as long as possible, the researchers wrote in their study. And in smaller studies, healthy eating habits have been linked with not only weight loss but also improved health, such as lower blood pressure, lower cholesterol levels, lower blood sugar levels and even improved cognitive function.
In another meta-analysis, published in October 2015 in the journal The Lancet, researchers concluded that low-fat diets were no better than other types of diets evaulated for long-term weight loss. The researchers looked at 53 studies that had weight loss as a goal, as well as other studies for which weight loss was not the primary goal (think back to the Women’s Health Initiative study, for example).
When comparing weight loss trials specifically to one another, the researchers found that low-carbohydrate diets resulted in greater weight loss than low-fat diets. For both the weight loss trials and the other trials, the researchers found that higher-fat diets resulted in greater weight loss than low-fat diets. And low-fat diets only resulted in greater weight loss when compared with a person’s usual diet, according to the study.
But none of the diets blew the others out of the water. The big picture that people can take away from this meta-analysis is that a low-fat, high-carb diet is not more effective than any other weight-loss diet, said Hu, who was the senior author of the study.
And the amount of weight loss induced by any of the diets was not very impressive, Hu added. Most people regained the weight they lost in six months to a year, he said. Studies have shown that many people tend to regain lost weight over time, and experts think that more research is needed on how to keep weight off successfully. “A low-carb diet may be a little bit more effective than a low-fat diet, but in the long run, both diets are not significantly different from each other in terms of weight loss,”