Diets work, but brands don’t make much difference, study finds


Which diet is the best for you? Whichever one you can stick with, according to a new meta-analysis of 48 different trials involving nearly 7,300 overweight and obese adults.

The findings, described in the Journal of the American Medical Assn., or JAMA, show that there’s relatively little difference in the effectiveness of various low-fat or low-carb diets, including the branded ones, from Atkins to Zone.

“Our findings should be reassuring to clinicians and the public that there is no need for a one-size-fits-all approach to dieting because many different diets appear to offer considerable weight loss benefits,” the study authors wrote.


Diet fads come and go, each claiming to tap into some secret advantage that previous weight-loss strategies did not. But it’s difficult to tell which diets are actually most effective – and that’s crucial information for overweight or obese individuals looking to successfully shed pounds by changing what they eat.

To provide some data-driven answers, a team led by Bradley Johnston of the Hospital for Sick Children Research Institute in Toronto examined 59 papers involving 48 randomized trials and sized up the examined diets’ average weight loss.

Low-carbohydrate diets edged out the low-fat diets (echoing an Annals of Internal Medicine study released Monday). Low-carb diets were linked to 8.73 kilograms of lost weight (19.25 pounds) at 6 months, and 7.25 kg (15.98 pounds) at 12 months. The low-fat diets were close behind, with 7.99 kg (17.61 pounds) lost in the first half-year and 7.27 kg (16.03 pounds) at the one-year mark.

Among individual, brand-name diets, the weight loss differences “were minimal,” the study authors wrote. For example, the Atkins diet nosed past the Zone diet at six months with just 1.71 kg (3.77 pounds) more weight lost.

“This supports the practice of recommending any diet that a patient will adhere to in order to lose weight,” the study authors wrote. In other words: Pick the one that’s easiest to stick with over the long haul.

Linda Van Horn of Northwestern University in Chicago, who was not involved in the paper, praised the study in a commentary. She noted that a healthful diet is ultimately about more than just macronutrients such as carbohydrates, fats and proteins.


Choosing the right foods with the right micronutrients – such as calcium, iron or folic acid – is key.

“Choosing the best diet suited to an individual’s food preferences may help foster adherence, but beyond weight loss, diet quality including micronutrient composition may further benefit longevity,” Van Horn wrote.

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