Review of ketogenic diet finds several risks for some patients

A ketogenic diet places pregnant women and kidney disease patients at risk of adverse health effects, according to a new review published in the journal Frontiers in Nutrition. The review also found that for most people, the possible long-term risks of the ketogenic diet, including heart disease, cancer, diabetes, and Alzheimer's disease, outweigh its possible benefits.

The term “ketogenic diet” generally refers to a diet that is very low in carbohydrate, modest in protein, and high in fat. This mix of fuels aims to induce ketosis, or the production of ketone bodies that serve as an alternate energy source for neurons and other cell types that cannot directly metabolize fatty acids.

Keto diets have been promoted for weight loss and, less commonly, for other health reasons—seizure disorders, obesity and weight management, type 1 and type 2 diabetes, fatty liver disease, cancer, Alzheimer’s disease, heart disease, kidney health, and pre-pregnancy and pregnancy—all of which were considered in this review. It also looked at potential long-term effects on health.

Researchers found that the only well-supported use for this dietary approach is to reduce seizure frequency in some individuals with drug-resistant epilepsy. Addition, key findings included:

1. Keto diets may be especially unsafe for women who are pregnant or may become pregnant—low-carb diets are linked to a higher risk of neural tube defectsin the baby, even when women take folic acid.
2. Higher-protein keto diets could hasten kidney failurein those with kidney disease.
3. Keto diets raise “bad cholesterol” levels for many patients.
4. Keto diets are presented as a panacea, but they are not likely to be safe long term.
5. Restricting carbohydrate skews the diet toward cancer-causing foods. In fact, typical keto foods have been linked to an increased risk of heart disease, cancer, diabetes, and Alzheimer's—often the very diseases they are touted to help.

“The typical keto diet is a disease-promoting disaster,” said Lee Crosby, RD, lead review author and nutrition education program manager at the Physicians Committee for Responsible Medicine. “Loading up on red meat, processed meat, and saturated fat and restricting carbohydrate-rich vegetables, fruits, legumes, and whole grains is a recipe for bad health.”