Small studies suggest a ketogenic diet may decrease fatigue and other symptoms in people with MS, but this approach to eating isn’t for everyone.

By Moira LawlerMedically Reviewed by Samuel Mackenzie, MD, PhDReviewed: March 31, 2022

The ketogenic diet isn’t just about weight loss, though that’s certainly the main reason many people are interested in it today. It was developed as a treatment for epilepsy in the 1920s, after physicians observed that fasting reduced seizure activity. Its origins may date back much further, however: There’s some evidence that ancient civilizations used versions of the ketogenic diet as an epilepsy treatment.

Called the keto diet for short, the ketogenic diet is high in fat, very low in carbohydrate, and moderate in protein. According to the Harvard T.H. Chan School of Public Health, if you’re following the keto diet, about 70 to 80 percent of your daily calories should come from fat, 10 to 20 percent from protein, and 5 to 10 percent from carbohydrate.

In contrast, the healthy eating patterns recommended in the Dietary Guidelines for Americans work out to approximately 20 to 35 percent of daily calories from fat, 45 to 65 percent from carbohydrate, and 10 to 35 percent from protein.

Consuming very low amounts of carbohydrate causes the body to burn fat for energy (rather than carbohydrate), which in turn causes the formation of chemicals called ketones as a by-product. The ketogenic diet is so called because it causes the body to generate ketones. This process of breaking down fat and creating ketones is called “ketosis.”

The keto diet is still used today by some people with epilepsy, particularly children, whose seizures aren’t controlled with medication, although even after all these years, the precise mechanism for the ketogenic diet’s antiseizure activity remains unknown.

There’s also some evidence that following the diet may help people with type 2 diabetes lower their blood sugar levels, possibly by encouraging weight loss.

And what about multiple sclerosis (MS)? Could the keto diet have any effect on the course of MS? A few researchers have been investigating this question in recent years, and here’s what they’ve found.

Research Findings on the Keto Diet and MS

It’s important to note that the human studies mentioned here are small, involving fewer than 100 people.

Reduces Fatigue and Depression

A study presented in April 2022 during the American Academy of Neurology’s 74th Annual Meeting found that the ketogenic diet is safe in people with MS and that they may experience less fatigue and depression and an improved quality of life while on it.

The study asked 65 participants with relapsing-remitting MS to rate their physical and mental health on a 0 to 100 scale, with higher scores representing better health, after six months on the diet.

Participants had an average physical health score of 67 at the start of the study compared with an average score of 79 at the end, and they had an average mental health score of 71 at the start of the study compared with an average score of 82 at the end, the researchers say.

In addition, on a scale of 0 to 10, with a score of 1 representing no disability, two representing minimal disability, and three, moderate disability but still able to walk, the average participant’s disability score at the start of the study was 2.3 and 1.9 at the end.

“Our study provides evidence that a ketogenic diet may indeed be safe and beneficial, reducing some symptoms for people with MS, when used over a six-month period,” says J. Nicholas Brenton, MD, the lead author of the study and an associate professor of neurology and pediatrics at the University of Virginia in Charlottesville. “However, it’s important that people with MS consult their doctor before making any big changes to their diet, and that they be regularly monitored by a physician and registered dietitian if on a ketogenic diet.”

The findings echo those of a similar, earlier study by Dr. Brenton and his colleagues that found that a type of keto diet called the modified Atkins diet improved fatigue and depression in people with multiple sclerosis.

A separate study published in the March 2020 issue of the Journal of the American College of Nutrition found that while people with MS achieved ketosis on the diet, they saw no improvements in fatigue and brain function. This study was smaller in size, with six participants given a paleo diet and five on a keto diet.

The smaller study also used a medium-chain triglyceride (MCT) keto diet, with coconut as its fat source. MCT is designed to be processed more efficiently — and produce more ketones — than other types of fat, according to the researchers.

Changes the Gut Microbiome

According to a review of previously published studies in the November 2021 issue of the journal Frontiers in Nutrition, researchers have found that people with MS who follow the keto diet for six months or more show evidence of potentially beneficial changes to their gut microbiome, with increases in healthy bacteria that may provide a neuroprotective effect against the damage caused by MS.

Protects the Brain, at Least in Mice With MS

A study published in September 2020 in the Journal of Agricultural and Food Chemistry found that mice with the same inflammation of the central nervous system seen in people with MS saw improvement in motor function when fed with a keto-based diet. They also saw reductions in damage to the hippocampus of the brain, which governs memory and other functions and is often adversely affected by MS.

Decreases Hunger and Inflammation While Increasing Lean Body Mass

A study published in May 2019 in the journal Nutrients examined the satiating (satisfying) effect of following the keto diet as well as its effects on muscle mass and level of oxidation in 27 people with multiple sclerosis. Oxidation is the normal process of cell decay, but excessive levels of oxidation, or oxidative stress, can lead to inflammation and tissue damage.

The researchers found that following a ketogenic diet for four months reduced subjects’ perception of hunger before and after lunch and dinner — although not before and after breakfast — and additionally led to an increase in lean mass, decrease in fat mass, and lowered levels of oxidation and inflammation.

Theories on Why the Keto Diet Might Help People With MS

Experts don’t yet know specifically what it is about the keto diet that leads to the changes observed in study subjects with MS — that’ll likely be the focus of future research — but there are a few theories.

Following the Diet Reduces Inflammation

MS is an inflammatory disease that causes damage to the central nervous system. Research shows that the keto diet decreases inflammation, increases mitochondrial biogenesis (the process by which cells produce new mitochondria), and reduces levels of oxidative stress, which may be beneficial in MS symptoms, Brenton says.

“Additionally, fat — as opposed to carbohydrate — is a more efficient source of energy for the brain, which may be particularly important in a brain that is battling inflammation, as is the case in MS,” he says.

People With MS May Respond Better to Ketones Than to Glucose

But inflammation isn’t the only cause of MS symptoms. As Mary Rensel, MD, a staff neurologist and the director of wellness and pediatric MS at the Cleveland Clinic’s Mellen Center for MS in Ohio, points out, people with MS also experience neurodegeneration, which is a progressive loss of function of the nerve cells and which contributes to progressive disability.

“One of the questions in MS is ‘What’s hurting the nerves?’ and one of the possible answers is that mitochondria are not working correctly,” Dr. Rensel says. Mitochondria are the “energy producers” within the cells, and according to Rensel, they may not use glucose correctly in people with MS. (Glucose is the primary fuel derived from carbohydrate.) These people may respond better to ketone bodies, which are produced as a result of ketosis.

“If you go into ketosis, you produce different energy makers — ketone bodies — and they get through the blood-brain barrier so they can get access to the brain and be used as an energy source,” Rensel says.

A study published in the November 2021 issue of the journal Neurology found that people with MS on a modified keto diet had lower levels of serum neurofilament light chain, a type of cell found in the central nervous system, or brain and spinal cord, that’s considered a possible sign of neurodegeneration. The researchers suggest a keto diet could be used as a possible treatment for progressive MS, in which neurodegeneration is the primary problem.

Weight Loss May Improve Quality of Life for People With MS

Another reason the diet may help is that it frequently leads to weight loss.

“It seems that people who are obese and have a poor diet may be at an increased risk of getting MS,” Rensel says. “And when you have MS, obesity and poor diet can lead to more progressive disability, so [being overweight] may indeed increase the risk of getting it or [negatively influence] the course of it.”

Brenton agrees that a healthy body weight, whether achieved through the keto diet or another method, is beneficial. “I do believe that weight loss can positively impact many comorbid symptoms of MS — including pain, fatigue, and mood disorders,” he says.

Risks and Side Effects of the Keto Diet

With all these potential benefits, why aren’t neurologists recommending the keto diet to all people with MS?

For one thing, it’s notoriously difficult to stick to.

“Ketogenic diets take effort to adhere to, and these types of diets will not fit into every individual’s life situation,” Brenton says.

The National Multiple Sclerosis Society also notes that a low-carb diet, and particularly the creation of ketones, can lead to fatigue, which is already a common problem in people with MS. And a low-carb diet that limits fruits, vegetables, and whole grains may contain insufficient amounts of vitamins, minerals, phytonutrients, antioxidants, and fiber.

Brenton adds that in his research, the most common side effects of the keto diet were constipation, menstrual irregularities, and diarrhea.

More Questions Than Answers About Keto and MS

The completed studies about the effectiveness of the keto diet for people with MS have been promising, but too small to draw broad conclusions.

“It’s interesting, but not necessary for everyone to follow this minute,” Rensel says. “At this very moment, we don’t know the perfect diet for multiple sclerosis patients.”

Those studying the keto diet for MS agree that more research is needed.

“While I think there are many benefits these diets can offer to people with MS, there needs to be more research into the ‘hows’ and ‘whys’ of these diets,” Brenton says. “I would further argue that the ketogenic diet needs further study. Our data demonstrate its safety over six months, but our study was not designed to study the long-term implications of this diet in MS. Thus, while our results support the rationale for a larger-scale study of ketogenic diets as a complementary treatment for MS, our data does not support its widespread adoption outside of a clinical trial.”

If you’re interested in following the keto diet to help manage your MS symptoms, be sure to speak with your physician first to discuss the pros and cons.

Additional reporting by Brian P. Dunleavy.