Although the ketogenic, or keto, diet was first popularized as an eating plan to control epilepsy, this eating style is now touted as a solution for everything from clearer skin to a slimmer waistline, though many of the claims are debatable.
To follow the diet, you prioritize fat and scale way back on carbs while keeping protein intake moderate. “A typical ketogenic eating pattern consists of 70 to 80 percent of total daily calories from fat, 15 to 20 percent from protein, and less than 10 percent from carbohydrates,” says Debra K. Sullivan, PhD, RD, a professor and the chair of the department of dietetics and nutrition at the University of Kansas Medical Center in Kansas City, Kansas. In doing so, you put your body into ketosis, a metabolic state during which your body relies on fat instead of carbs for fuel. Theoretically, this leads to weight loss and associated benefits.
But the keto diet is restrictive — and it’s not for everyone. Side effects abound and may include nutrient deficiencies and constipation. Plus, certain people, including those with heart health issues, liver disease, and chronic kidney disease, are better off avoiding keto, Dr. Sullivan says. If you’re managing a chronic health condition, check with your healthcare team before trying keto.
If you’re interested in this high-fat, low-carb eating style, here are some of the potential benefits you may reap.
Keto Diet Benefits With Some Research Support
Among the touted benefits of the keto diet, the following have the most scientific backing. That said, the research cited below still has limitations of note.
Promotes Short-Term Weight Loss
Ketosis is the purported weight loss mechanism in keto. But that’s not the only factor at play. Initial losses on keto might merely be water weight. “When there are a lot of carbohydrates in the diet, the body stores some of the extra glucose along with water,” Sullivan says. “When you cut back on carbohydrates, the body stops storing glucose and uses the remaining stores. As a result, there is also less water stored throughout the body.”
Perhaps for this reason, keto appears to be most effective as a short-term weight loss strategy. One review of 13 randomized, controlled trials found that after a year, ketogenic diets helped people lose about 2 kilograms, or 4.4 pounds, more than low-fat diets. But higher-quality studies showed no difference between the two. “Many studies show that people following the keto diet can lose 5 to 10 percent of their body weight within the first six months,” says Sullivan. “Like most diets, however, long-term success is more challenging.” In the aforementioned study, for example, weight loss peaked at about five months but was often not sustained.
Of course, it’s not impossible to stick with keto longer term. Sullivan points out that, despite the diet’s restrictive nature, many keto-friendly packaged foods, restaurant menu sections, and online communities can help people stay committed. But whether you’ll continue to lose weight is an open question. “More research is needed to fully understand the effects of following the diet for extended periods,” she says.
Helps Control Epilepsy
Researchers originally developed keto in the 1920s as a dietary strategy to control epilepsy, and people with that condition use it to this day. “The ketogenic diet helps control epilepsy by shifting the body's energy source from carbohydrates to fats, which produces ketones,” says Michael Snyder, MD, medical director of the HCA HealthOne Denver Center for Weight Loss and Bariatric Surgery and in-house obesity specialist at FuturHealth. “Ketones, which are alternative fuels for the body that are made when glucose is in short supply, are thought to improve seizure control in individuals with epilepsy.” Research notes that the diet can be considered as an alternative for people who have seizures that do not respond to traditional medications.
Dr. Snyder emphasizes, however, that a healthcare team (including a neurologist and dietitian) needs to supervise a patient using the keto diet to control epilepsy. He also points out that it’s most effective for this purpose when people stick to its original parameters, consuming the vast majority of their calories from fat.
May Support Brain Health
While the first few days on the keto diet may involve so-called “brain fog,” Snyder says this usually clears — sometimes even leaving people feeling greater mental clarity. He says this is due to switching to an alternate fuel source for the brain. One study supports that notion, finding that a minimal intake of carbohydrates and high intake of fat increased the production of ketone bodies, potentially yielding better cognition.
Extra ketones may also offer neuroprotection for aging brain cells, enhancing mitochondrial function and reducing inflammation, per a review. Because of these effects, some researchers believe that a ketogenic diet might be helpful for managing Alzheimer’s disease.
Not surprisingly, the high-fat, low-carb nature of keto can influence blood sugar levels.
A small trial randomized 33 people with prediabetes or type 2 diabetes to follow either the keto diet or the Mediterranean diet, and both diets lowered A1C significantly and equally.
A separate meta-analysis, meanwhile, concluded that a keto diet was superior to control diets for glycemic control in people with diabetes.
Be warned, though, that a keto diet can also lead to hypoglycemia — aka low blood sugar levels — if you take medication to lower your blood sugar. Snyder emphasizes the importance of consulting your doctor to determine whether it’s the right choice for diabetes management. Due to its risks, he says that a keto diet is not the typical standard of care for people with type 1 or type 2 diabetes.
May Benefit Skin Health
A lesser-known, more recently discovered benefit of keto: its potential effects on skin. In a small study, women with moderate acne experienced notable improvements in its severity after going on a keto diet for 45 days. Another study suggests that the diet could be used to treat other skin conditions, like psoriasis, hidradenitis suppurativa, and prurigo pigmentosa.
On the other hand, some animal research found that the high-fat eating pattern could actually cause inflammation similar to psoriasis on the skin. Future studies may shed more light on exactly how a keto diet affects skin health.
Keto Diet Benefits
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Proposed Keto Diet Benefits That Need More Research
Some initial research has linked a keto diet to other health benefits, but these studies are weaker, and the claims require further exploration before you rely on the keto diet for them.
Increases Effectiveness of Cancer Treatment
Keto may be used in combination with chemotherapy and radiation, some preliminary case and open-label studies suggest. At the same time, some animal research indicates that the diet could actually promote cancer metastasis. The bottom line is that rigorous research in humans on the potential role of keto in supporting cancer treatment is necessary before keto is recommended for people with cancer.
Benefits Heart Health
A review notes that similar to other diets, a keto diet may reduce high blood pressure (stemming from the loss of body weight) and improve the function of vascular cells. But the American Heart Association states that the diet does not align with current heart-healthy eating guidelines. “The keto diet may offer short-term benefits like lowering blood pressure, but its long-term effects on heart health may not make it the best option,” says Snyder.
May Improve Fertility in Women With PCOS
In one systematic review that evaluated 170 women with polycystic ovary syndrome (PCOS), those who followed a ketogenic diet for 45 days or more had improved reproductive hormones. It is cause for hope that the diet could make it easier for women to conceive (PCOS can impair fertility) — but it is not a conclusive endorsement for the diet as a hormone therapy. The sample sizes in these studies have been relatively small, and larger, more rigorous studies are still needed.
The Takeaway
A keto diet may be a useful weight loss strategy, especially in the short term.
Quality research shows that the diet helps control epilepsy and may help manage blood sugar, support brain health, and improve acne.
Before you load up on fat and dial back on carbs, run it by your healthcare team — they can help you make the best decision for your well-being.
Reyna Franco, RDN, is a New York City–based dietitian-nutritionist, certified specialist in sports dietetics, and certified personal trainer. She is a diplomate of the American College of Lifestyle Medicine and has a master's degree in nutrition and exercise physiology from Columbia University.
In her private practice, she provides medical nutrition therapy for weight management, sports nutrition, diabetes, cardiac disease, renal disease, gastrointestinal disorders, cancer, food allergies, eating disorders, and childhood nutrition. To serve her diverse patients, she demonstrates cultural sensitivity and knowledge of customary food practices. She applies the tenets of lifestyle medicine to reduce the risk of chronic disease and improve health outcomes for her patients.
Franco is also a corporate wellness consultant who conducts wellness counseling and seminars for organizations of every size. She taught sports nutrition to medical students at the Albert Einstein College of Medicine, taught life cycle nutrition and nutrition counseling to undergraduate students at LaGuardia Community College, and precepts nutrition students and interns. She created the sports nutrition rotation for the New York Distance Dietetic Internship program.
She is the chair of the American College of Lifestyle Medicine's Registered Dietitian-Nutritionist Member Interest Group. She is also the treasurer and secretary of the New York State Academy of Nutrition and Dietetics, having previously served in many other leadership roles for the organization, including as past president, awards committee chair, and grant committee chair, among others. She is active in the local Greater New York Dietetic Association and Long Island Academy of Nutrition and Dietetics, too.
Sarah Garone is a licensed nutritionist, registered nutrition and dietetics technician, freelance health and wellness writer, and food blogger in Mesa, Arizona. She has written for TheWashington Post, Healthline, Greatist, Verywell, and Eat This, Not That, among other outlets. She is a member of the Academy of Nutrition and Dietetics.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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