Background

Low-fat or low-carb, which is better for weight loss?[1] It is time, once again, for an updated look at the whole body of evidence.

The study

This meta-analysis included 38 randomized controlled trials that investigated the effects of low-carb diets, low-fat diets, or both on weight loss and blood lipids. The trials lasted 1–24 months. The 6,499 total participants were aged 33-58 and had a mean BMI of 22–44.

The results

About 1 kg more weight was lost by the low-carb dieters, overall. This difference was most notable when the diets ranged from 6 to 12 months.

Triglycerides were reduced more by low-carb diets, whereas LDL-C, HDL-C, and total cholesterol were reduced more by low-fat diets.

On most criteria, most studies a had low or moderate risk of bias.

Note

That low-fat outperforms low-carb with respect to certain blood lipids comes as no surprise, but this is still important information for people at high risk of cardiovascular disease.

When it comes to weight loss, though, the best diet is mostly a matter of personal preference.

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This Study Summary was published on January 5, 2021.