Scientists Reveal Which Low-Carb Diets Work Best for Weight Loss

After a month of festive indulgence, weight loss is one of the most popular New Year's resolutions. But it can be hard to know which diet is best for you for losing weight and successfully keeping it off.

Cutting down on carbohydrates is a common dieting strategy—think lettuce sandwich wraps and zucchini pasta—but new research has shown that not all low-carb diets are equal when it comes to losing weight.

In clinical trials, low-carb diets have been shown to be effective in achieving short-term weight loss. One study in 2008 found that a diet consisting of 20 percent carbohydrates (compared to the average 50 percent in America) led to an average loss of 10 pounds over a two-year period. This was higher than those sticking to a Mediterranean or low-fat diet.

But whether these low-carb diets lead to long-term, sustainable weight loss is still largely understudied.

In a recent study published in the scientific journal JAMA Network Open, researchers at the Harvard T.H. Chan School of Public Health in Boston analyzed data from three large ongoing health surveys to assess the impact of these diets on long-term weight loss over a four-year period.

Overall, the team observed a U-shaped association between low-carb diets and weight change over the four-year period.

In other words, while the low-carb diets did result in short-term weight loss, people tended to put the weight back on in the long term. However, when the researchers looked closely at what the participants were actually eating, a different pattern began to emerge.

Those who had a diet rich in healthy, plant-based foods saw significantly less weight re-gain in the long-term than those who ate more animal proteins and fats. Weight gain was also seen in those who opted for more refined carbohydrates within their low-carb allowance. In particular, processed meats, potatoes and sugar-sweetened beverages were associated with long-term weight re-gain, while whole grains, vegetables, fruits, nuts and yogurt were associated with less weight gain.

The study does have some limitations, namely that the data was self-reported by the participants. However, it does still highlight the importance of food quality as well as quantity when it comes to dieting and weight loss.

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