Diets for Weight Loss Are Effective, But the Benefits Dwindle as Time Goes On

According to new research published in The BMJ, most diets lead to weight loss and lower blood pressure in the beginning, but those effects largely disappeared a year after the diet’s start.
Changing from a “diet” mindset into one focused more on long-term strategies can help extend these benefits for a significant amount of time.

When embarking on a weight loss journey, there are plenty of options when it comes to diets to follow, from Mediterranean and DASH approaches to keto and macro tracking. The biggest question: Which one should you follow? Recent research in The BMJ suggests it doesn’t actually matter what diet you embrace, since most of them will provide results—but there’s a catch.

Researchers compared 17 diets that were studied in 121 nutrition trials, totaling nearly 22,000 participants. They found that all diets had some effect on reducing weight and lowering blood pressure over the initial six months.

Low-carb and low-fat options had about the same modest results on weight, but the latter is slightly more beneficial in regards to blood pressure, the study noted. The diets with the most weight reduction were Atkins, DASH, and Zone, but none of the diets significantly improved levels of HDL (good) cholesterol.

The most notable conclusion, though, is that while most diets that changed macronutrient distributions showed some degree of weight loss and improvements in blood pressure at the six-month mark, those effects largely disappeared a year after the diet’s start.

Does this mean the takeaway here is that you shouldn’t even give weight loss and blood pressure management a shot, since you’ll be back to square one anyway? Not at all, said Helen Truby, Ph.D., coauthor of an accompanying editorial on the study and director of nutrition and dietetics at Monash University in Australia.

Instead, she told Runner’s World, the message of this study should be that you could choose any popular diet and you’ll likely see results, but that after a certain period of time—for example, about six months—the focus should shift to weight maintenance.

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For instance, that might involve changing from a “diet” mindset into one focused more on long-term strategies, said Truby, particularly when it comes to nutrition. Considering that the Mediterranean model fared so well here, the researchers suggest that could be the eating plan with the most staying power in terms of maintaining weight loss and cardiovascular benefits.

National dietary guidelines in any country are failing to resonate with the public, Truby said, and this study shows that diets—and particularly those that have numerous restrictions—are less helpful in the long run than focusing on healthy eating basics like eating more vegetables, legumes, and whole grains, and limiting your amount of sugar, salt, and alcohol.