While extremely low-carbohydrate diets like fat-forward keto can aid in short-term weight loss, they have mixed effects on other health markers, according to a scientific statement issued by the National Lipid Association and published in the Journal of Clinical Lipidology.

Based on a review of existing research, investigators pinpointed a few benefits of low-carb diets, including more weight loss over the first 6 months, appetite suppression and lower blood sugar in people with diabetes. But a keto-style diet can drive up levels of low-density lipoprotein cholesterol, a troubling form of cholesterol that can raise heart disease risk, and the diet appears to offer no greater weight loss after 1 year than plans that allow for greater carbohydrate consumption. The report also stresses that extremely low-carb diets can be harder to stick with over time and often restrict nutrient-dense foods that offer health benefits.

The investigation was limited by the dearth of long-term trials on low-carb diets and health outcomes like heart disease and diabetes.