Diets often emphasize low-fat or low-carb eating patterns, but which is best for dropping pounds? Some people may take an individualized approach to this question, believing genetic or metabolic tests are needed to choose the best diet, but a new study suggests low-fat and low-carb diets are fairly even in terms of weight loss, regardless of your genetics or insulin response to sugar. For the study, published in JAMA, researchers selected 609 healthy participants who were 18 to 50 years old and were overweight or obese, but did not have diabetes. They were randomly divided into a healthy low-fat diet group and a healthy low-carb diet group. Throughout the year-long study, participants attended 22 educational sessions where they were instructed to limit their intake of either fats or carbs to 20 grams per day for the first eight weeks, after which they were guided to slowly increase their intake to the lowest amounts they felt they could sustain for the long term. They also received guidance around improving their diet quality by increasing their vegetable intake and avoiding highly processed, high-sugar, and trans-fat containing foods. On average, the low-fat group achieved a diet consisting of 48% carbs, 29% fat, and 21% protein, and the low-carb group achieved a diet consisting of 30% carbs, 45% fat, and 23% protein. In addition to monitoring weight changes, the researchers assessed each participant’s insulin response to sugar and factors in their genetic profile related to metabolism. At the end of the study, the researchers found:
Weight loss was not significantly different between the two diet groups: the healthy low-fat diet group lost almost 12 pounds, and the healthy low-carb diet group lost a little over 13 pounds.
Neither genetic profile nor insulin response were associated with the likelihood of successfully losing weight on either diet.
While these two diets had different components, one thing they had in common was that they emphasized nutritious foods, which makes for the argument that a healthy diet—whether low-fat, low-carb, or individualized by predictors of metabolism—may be the secret to weight loss. If you’re looking for a healthy diet, both the DASH and Mediterranean diets have been associated with a myriad of health benefits. Both diets include high intakes of fruits, vegetables, and whole grains, and modest intakes of chicken and fish, which is a tried-and-true recipe for a healthy diet.