Study Links Keto Diet to Severe Long-Term Health Risks

The negative long-term consequences of ketogenic diets may far outweigh any potential short-term benefits, according to a comprehensive review published in Frontiers in Nutrition.

Keto diets have skyrocketed in popularity over the last decade due to their ability to promote quick weight loss. Typically very low in carbohydrates, modest in protein, and high in fats, the aim of keto diets is to push the body into ketosis—the state in which the body uses fat for fuel. Foods like red meat, fish, nuts, cream, eggs, cheese, oil, and non-starchy vegetables are given the green light while starchy vegetables, fruit, whole grains, beans, and lentils are avoided as much as possible. 

For the meta-analysis, published in July 2021, a group of physicians, researchers, and registered dietitians analyzed more than 100 peer-reviewed studies on keto diets to identify long-term effects. They found that people who follow such diets have a significantly increased risk of developing heart disease, LDL cholesterol buildup, kidney failure, Alzheimer’s disease, diabetes, and cancer. They also discovered that keto diets are particularly dangerous for people who are currently pregnant or may become pregnant. Low-carbohydrate diets are linked to birth defects, particularly neural tube defects, and gestational diabetes even if the pregnant person is taking folic acid supplements. Additionally, for those living with chronic kidney disease (CKD), the high amounts of protein consumed on the keto diet can place excess stress on the kidneys and worsen the long-term internal damage of CKD. 

So why does this diet have such negative side effects? The study’s authors suggest that it has to do with the nutrient quality of the food being eaten.

“The foods that are emphasized on a keto diet are the very products that cause colon cancer, heart disease, and Alzheimer’s disease,” says study co-author Neal Barnard, MD, FACC, president of the Physicians Committee for Responsible Medicine and an adjunct professor of medicine at George Washington University School of Medicine. “New research also shows that these same foods raise the risk for severe COVID-19.”

This sentiment is echoed by lead review author Lee Crosby, RD. “The typical keto diet is a disease-promoting disaster,” says Crosby. “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.”

Originally developed in the 1920s as a treatment for patients with severe drug-resistant epilepsy, the keto diet has been shown to be effective for reducing seizures in extreme cases. Scientists believe the diet decreases seizures by making less glucose available to fuel neurons. And although the study authors concluded that eating keto could be beneficial for seizure management, they say the risks far outweigh the rewards for most  people.

Instead of going keto, Barnard suggests a whole food, plant-based diet: “On a low-calorie diet, people might lose weight, but they have to go hungry to do it. On a keto diet, they might lose weight but they feel guilty if they have an apple, banana, slice of bread, or a cookie. On a plant-based diet, you get the best of all worlds: weight loss, delicious food, better overall health, and you’re never hungry.”

To learn more about a whole-food, plant-based diet, visit our Plant-Based Primer. For meal-planning support, check out Forks Meal Planner, FOK’s easy weekly meal-planning tool to keep you on a healthy plant-based path.