Study: Keto Diet May Lead to Long-Term Health Risks

Keto ingredients

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Key Takeaways

  • A new study suggests that the risks associated with a keto diet may outweigh benefits like accelerated weight loss.
  • Researchers say that following a keto diet is especially risky prior to or during a pregnancy, and for people who have chronic kidney disease.
  • One of the major concerns for this restrictive diet is that many people tend to eat too much red meat and processed foods with very few fruits and vegetables. 

The popular ketogenic diet, also known as keto, may lead to long-term health risks that outweigh short-term benefits, according to a new study published in Frontiers in Nutrition.

By analyzing available literature on keto, researchers found that the diet was especially unsafe for pregnant people, people who may become pregnant, and those with kidney disease. They concluded that keto could also lead to long-term health complications, such as cancer, heart disease, and Alzheimer’s Disease for most people. 

Keto is typically very low in carbohydrate, modest in protein, and high in fat. This diet includes foods like meats, fish, nuts, and fibrous vegetables while eliminating most fruits, grains, beans, starchy vegetables, and sweets.

It aims at reaching ketosis, the state in which the body uses fat for fuel. Glucose otherwise provides the primary source of energy, deriving from carbohydrates. By restricting carbohydrate intake, the keto diet forces the body to break down fat into ketones as an alternative energy source.

“The idea for people on this diet is that if you are burning fat, you may also burn body fat,” Shivam Joshi, MD, a nephrologist, clinical assistant professor at NYU Grossman School of Medicine and a co-author of the study, tells Verywell.

Keto has historically been used to treat intractable epilepsy, a severe drug-resistant seizure disorder. However, more people have adopted this restrictive diet for weight loss and diabetes management.

Joshi says that some people do lose weight with the keto diet, but the short-term weight loss is likely a result of reduced calorie intake. Keto is on par with other restrictive calorie diets, he adds, but people should be aware of its side effects.

Risks Associated With Keto

Neal Barnard, MD, FACC, an adjunct professor of medicine at the George Washington University School of Medicine and a co-author of the study, tells Verywell that keto diets contain the types of foods that are associated with cancer risks. 

A keto diet emphasizes the consumption of animal products while limiting many nutrient-rich vegetables, fruits, and whole grains. As a result, keto is low in many vitamins, minerals, and fiber. 

Restricting carbohydrates prior to or during pregnancy is linked with increased risks of birth defects and gestational diabetes, the researchers found. Since 40% of pregnancies in the United States are unplanned, a low-carbohydrate diet is considered risky for anyone who could become pregnant.

Barnard adds that most human beings are prone to risks associated with a highly restrictive keto diet. “If a cat eats meat every day for the cat’s whole life, she’ll never get a heart attack,” he says. “If you eat meat for a week, your cholesterol levels are going to go up in many cases and you may get heart disease.”

Potential Health Risks From Keto Diet

  • For pregnant people, even those who take a folic acid supplement, their babies might develop neural tube defects.
  • Since large amounts of protein can put stress on the kidneys, keto may pose greater risks for people who have chronic kidney disease.
  • Sustained ketosis in people with Type 1 Diabetes can lead to insulin resistance and other complications.
  • Keto can rapidly increase total levels of cholesterol, including low-density lipoprotein cholesterol ("bad cholesterol"), which could be especially dangerous for those with high risk of cardiovascular disease.

How to Approach the Keto Diet Safely

In recent years, keto has become a trendy diet for losing weight and managing some other health conditions. However, Barnard suggests that there’s usually a better dietary approach than keto.

“Carbohydrates aren’t bad. Grains and beans and fruits and vegetables should be the staples of our diets,” he says, adding that plant-based diets can predictably lower cholesterol, blood pressure, and blood sugar.

Some followers of the keto diet have broken away from the traditionally limiting format in favor of a plant-based or vegan keto diet. 

Liz MacDowell, a certified holistic nutrition consultant and author of “Vegan Keto, runs the food blog Meat Free Keto. She practices what she calls a “quasi-keto” diet. Liz adds fruits, vegetables, and beans into her diet, which can be controversial in the keto world. She’s even received backlash for sharing a post on her Instagram about strawberries. 

“Consuming those micronutrients far outweighs whatever challenge your body now faces to maintain ketosis with those minimal extra grams of carbohydrates,” MacDowell tells Verywell. “Fruit is not the worst thing. It has sugar but it has so many other positive things in it, so many good phytochemicals and micronutrients.”

For anyone looking to add more fresh produce into their keto routine, Liz emphasizes one important thing: Don’t stress. 

“We have enough stress so we don’t need to be stressing about eating one carrot too many or one cherry tomato too many,” she says.

Strict keto diets, even if they are plant-based, are still concerning to some medical practitioners because they often limit healthy protein sources. While keto could be great for weight loss, more research is necessary for its long-term safety for people with metabolic diseases and cardiovascular risk factors.

What This Means For You

Ultimately, you can decide what diet works best for your health goals. If you want to start a keto diet, consider its risks and whether it's sustainable for you. Discuss with your doctor or nutritionist about how the dietary plan could affect your health. While keto works for some people to control seizures or lose weight, there are long-term risks that may outweigh any short-term benefits.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Ahrens K, Thoma M, Copen C, Frederiksen B, Decker E, Moskosky S. Unintended pregnancy and interpregnancy interval by maternal age, National Survey of Family Growth. Contraception. 2018;98(1):52-55. doi:10.1016/j.contraception.2018.02.013

  4. Desrosiers T, Siega-Riz A, Mosley B, Meyer R. Low carbohydrate diets may increase risk of neural tube defects. Birth Defects Res. 2018;110(11):901-909. doi:10.1002/bdr2.1198

  5. Haring B, Selvin E, Liang M et al. Dietary protein sources and risk for incident chronic kidney disease: results from the atherosclerosis risk in communities (ARIC) study. Journal of Renal Nutrition. 2017;27(4):233-242. doi:10.1053/j.jrn.2016.11.004

  6. Kanikarla-Marie P, Jain S. Hyperketonemia and ketosis increase the risk of complications in type 1 diabetes. Free Radical Biology and Medicine. 2016;95:268-277. doi:10.1016/j.freeradbiomed.2016.03.020

  7. Salas Noain J, Minupuri A, Kulkarni A, Zheng S. Significant impact of the ketogenic diet on low-density lipoprotein cholesterol levelsCureus. 12(7):e9418. doi:10.7759/cureus.9418