Can a low-carbohydrate diet help keep weight off?

For your entire life you have been bombarded with information about which diet is the best to help you lose weight. Like many other people, you might have tried one or even a dozen diets, but it took a bit of trial and error for you to find which diet worked for you. Now, you are on to the hard part. You have finally lost the weight, but how do you keep it off? That is the million dollar question, right?

In a new study in The BMJ, researchers sought to determine if a low-carbohydrate diet might help mitigate the dreaded weight regain that occurs when a person loses weight. We know that when a person loses weight their energy expenditure, or metabolism, decreases. Until now, we have not known whether a certain diet composition would affect this metabolic adaptation that inevitably occurs.

The BMJ study researchers studied 164 adults with overweight or obesity — classified as a body mass index (BMI) of 25 or greater — between August 2014 and May 2017. Individuals in the study were assigned to one of three test diets:

• high carbohydrate content (60% carbohydrate diet)
• medium carbohydrate content (40% carbohydrate diet)
• low carbohydrate content (20% carbohydrate diet)

The investigators then measured several factors during the participants’ weight loss maintenance phase. The results were very interesting. Here is what they discovered:

• The total energy expenditure (TEE) of persons on a low-carbohydrate diet was much higher than persons in the medium or high carbohydrate groups.
• Ghrelin, a hormone that causes one to feel hunger and takes one longer to feel full, was lower in the low-carbohydrate group.
• Leptin, a hormone that causes one to feel full quickly, was lowest in the low-carbohydrate group.

Overall, the study demonstrates that, in the short term, a low-carbohydrate diet might make it easier for persons who have lost weight to keep it off, compared to moderate- and high-carbohydrate diets.

So, you’ve lost weight. Should you switch to a low-carbohydrate diet? The jury is still out. While the results clearly demonstrate that a low-carbohydrate diet fared best with regard to weight maintenance, the study was only performed over the course of 20 weeks. What would happen if the study was lengthened to a year, or two years? Would we still see such a clear difference in TEE after a much longer period of time? I think we must wait to see those results.

In the meantime, it might be a good idea to evaluate the carbohydrate content of your diet if you are struggling to maintain weight loss. If your carbohydrate content is moderate or high, you might consider decreasing your carbohydrate intake. However, remember that there is not a “one size fits all.” Just because one person responds to a low-carbohydrate diet, it does not mean that you will too. Listen to your body cues. You and your body cues are the most important part of the equation.

If you continue to struggle, seek out care with an obesity medicine physician who can help tailor your plan to fit you. You can search for a board-certified obesity medicine physician in your area on the American Board of Obesity Medicine website.

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