Low-Fat vs. Low-Carb: Which Is Better for Weight Loss?

Fresh fruit in a waffle cone
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There are so many diets out there for weight loss, it is hard to know where to start and which to choose. Some recent research helps shed light on the long-running low-fat vs. low-carb debate.

Rethinking Low-Fat

A number of studies have now shown that low-fat diets may not be the best choice when it comes to weight loss, or even when it comes to preventing cardiovascular disease.

One study that looked at weight-loss results in individuals following either a low-fat or low-carb diet for a year found that those who followed the low-carb diet lost nearly 8 pounds more than did those who followed the low-fat diet.

Importantly, those on a low-carb diet also saw a greater reduction in cholesterol-based cardiovascular risk factors.

In a review of over 50 clinical trials that have examined the low-fat vs. low-carb question, researchers concluded that evidence from randomized controlled trials “does not support low-fat diets over other dietary interventions for long-term weight loss.”

But Better Than Nothing

However, when compared to no diet at all, the low-fat diet did turn out to be more effective for weight loss. The lesson here seems to be that any dietary change aimed toward weight loss is a better step to take than doing nothing at all.

If you’re going to change your diet, though, why not get the “biggest bang for your buck” and go for the most effective dietary plan?

Higher-Fat Diets With Added Health Benefits

Higher-fat diets that focus on good fats (monounsaturated and polyunsaturated fats), like the Mediterranean diet, have been found to prevent cardiovascular disease and breast cancer as well as slow cognitive decline, all while resulting in modest weight loss.

In the latest results released from the PREDIMED (Prevención con Dieta Mediterránea) trial at the 2015 American Heart Association meeting in Orlando, Florida, the higher-fat Mediterranean diet actually showed more weight loss (a little over 2 lbs.) than the low-fat control diet.

Researchers believe that this may be due to the nature of the fats inherent in the Mediterranean diet.

Olive oil and nuts fall into the category of “good fats,” which are low in saturated fat and high in mono- and polyunsaturated fats. They are also high in polyphenols, nutrients which have been found to play a role in preventing cardiovascular disease and other chronic diseases.

Thus, the healthy fats are likely processed and metabolized differently by the human body, and the result is reassuring: eating more of these healthy fats does not result in weight gain at all.


Bazzano LA, Hu T, Reynolds K, et al. Effects of low-carbohydrate and low-fat diets: a randomized trial. Ann Intern Med 2014;16:309-318.

de Lorgeril M, Salen P, Martin JL, et al. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation 1999;99:779-785.

Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013;368:1279-1290.

Hu T, Bazzano LA. The low-carbohydrate diet and cardiovascular risk factors: evidence from epidemiologic studies. Nutr Metab Cardiovasc Dis 2014;24:337-343.

Tobias DK, Chen M, Manson JE, et al. Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis. Lancet Diabetes Endocrinol 2015;3:968-979.

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