Keto diet isn’t cure for schizophrenia, contrary to US health secretary Robert F. Kennedy Jr.’s claim

During his “Take Back Your Health” national tour, U.S. Health Secretary Robert F. Kennedy Jr. told a crowd in the Tennessee State Capitol on 4 February 2026 that a doctor at Harvard had cured schizophrenia with “keto diets”. His claim was shared across social media platforms like TikTok and X. In his address, Kennedy also implied that people’s diet was causing mental illness, claiming “We now know that the things that you eat are driving mental illness in this country”.

It is not the first time that Kennedy, who has no medical training, made claims that downplay or undermine the role of psychiatry in the treatment of mental illness.

During his Senate confirmation hearing in January 2025, he suggested antidepressants were more addictive than heroin, something that is not substantiated by the evidence. And in November 2025, he implied that medications used to treat psychiatric disorders could be responsible for “mass violence” in a post on X, even though there’s no evidence that such medications increase the risk of mass violence.

In this review, we take a look at the scientific evidence for this claim and show why Kennedy’s claim of a schizophrenia “cure” is unsubstantiated.

No evidence eating more protein treats mental illness

Schizophrenia is a serious, chronic mental illness characterized by “significant impairments in the way reality is perceived and changes in behaviour”. Symptoms include hallucinations, delusions, and disorganized behavior. Treatment includes medication as well as talking therapy. A third of people who are affected eventually experience complete remission of symptoms, but most will have to manage the condition all their lives.

There is indeed some scientific evidence to suggest that metabolic dysfunction in the brain, in particular affecting glucose metabolism, could play a key role in schizophrenia and other mental disorders^[1,2].

Because the ketogenic diet forces cells to switch from using glucose as fuel to ketones instead, scientists hypothesize that the diet could address the metabolic dysfunction seen in various mental disorders, leading to improvements in symptoms and potentially even remission.

In fact, the ketogenic diet is already being used as a medical treatment for pediatric epilepsy that doesn’t respond to medication, underscoring how a metabolic shift can be effective for treating conditions affecting the brain.

Having said that, medical ketogenic diets are specialized and require supervision by medical professionals. They are difficult to follow and their highly restrictive nature makes maintaining a nutritionally balanced diet challenging.

Nowadays, the term “ketogenic diet” is popularly applied to dietary patterns that don’t necessarily resemble medical ketogenic diets, like the carnivore diet, a fad diet that restricts consumption to mostly or only animal-based foods. Indeed, Kennedy called on people to “eat protein” during his speech, even though the ketogenic diet isn’t defined as a high-protein diet, but one that is high in fat and low in carbohydrate.

But Kennedy’s exhortation to eat protein is in line with newly unveiled dietary recommendations for Americans, which encourage the consumption of more red meat and full-fat dairy products—a move aimed at “ending the war on protein”, say the recommendations.

Only, there’s no evidence to support the association between protein intake and mental illness implied in Kennedy’s speech. FactCheck.org examined U.S. health officials’ claim that the new dietary guidelines address low protein levels in children and adults. They concluded that while certain groups in the population, like the elderly, would benefit from increasing protein intake, the majority of the American population isn’t suffering from a protein deficiency.

Case reports, small studies contain promising findings but aren’t generalizable

When Kennedy referenced “a doctor from Harvard” in his speech, he was likely talking about Christopher Palmer, an assistant professor of psychiatry at Harvard Medical School, who co-authored two case reports that were published in 2019^[3].

Both cases were observed in women who’d been diagnosed with schizophrenia and taking multiple medications for the condition. Both began the ketogenic diet for reasons unrelated to schizophrenia. One woman noticed that her symptoms greatly improved shortly after starting the ketogenic diet, and that the symptoms didn’t return after she stopped taking her medication.

It should be noted that the other stopped taking her medications shortly after starting the ketogenic diet and was later hospitalized after experiencing severe psychosis, requiring another round of medication. While she did eventually improve, her road to recovery was more complicated than Kennedy’s description let on.

Palmer also authored another report about two other people whose schizophrenia symptoms improved after they started the ketogenic diet in 2017^[4].

Apart from these case reports, there are also preliminary studies from other scientists suggesting that the metabolic shift triggered by a ketogenic diet could be beneficial for some people with mental disorders.

One study performed in France looked at 31 adults who had been diagnosed with severe mental illness and were admitted to a psychiatric hospital^[5]. They were placed on a ketogenic diet under supervision. The length of time they spent on the diet varied from person to person, ranging from six days to about eight months. All participants continued to receive standard psychiatric treatment during the study.

The study reported “substantial and statistically significant improvements in symptoms of depression and psychosis not observed during previous hospitalizations”, although three patients were unable to follow the ketogenic diet for more than two weeks and were therefore excluded.

But the study contained several limitations. For starters, there was no equivalent control group to compare outcomes with. Also, most of the participants were women (70%), so it is unclear whether the same results would have been observed if there had been roughly the same proportion of men and women. In addition, the study wasn’t blinded, meaning that bias could influence the results.

Another study performed in the U.S. looked at metabolic and psychiatric changes in 21 people diagnosed with either schizophrenia or bipolar disorder after four months on the ketogenic diet^[6]. Participants remained on their standard psychiatric treatment during the study.

The study reported that participants generally showed improvements in both metabolic markers such as weight, waist circumference, and cholesterol level, as well as improvements in psychiatric outcomes.

Like the French study, this one also comes with significant caveats. It didn’t have a control group and was quite small. Furthermore, important demographic factors like socioeconomic status weren’t accounted for in the study, which could have an effect on the results.

More broadly, a systematic review of the scientific literature published in 2023 looked at the effect of low carbohydrate and ketogenic diets in treating mood and anxiety disorders^[7]. The review included Palmer’s case reports and the study in France mentioned earlier.

The findings of the review effectively highlighted how anecdotal case reports dominated the small evidence base. While there is biological plausibility in the hypothesis that a low-carbohydrate diet could lead to improvement in different mental disorders, there was ultimately a lack of high-quality evidence to demonstrate the diet’s efficacy in people. There was also a lack of data regarding its safety, which is a concern since a ketogenic diet could affect the way certain psychiatric medications are metabolized in the body.

Speaking to the New York Times, Palmer said that Kennedy was “not accurate” in describing his findings about the keto diet’s effect on schizophrenia. He expressed appreciation for Kennedy’s “enthusiasm for [his] work”, but clarified that he “never claimed to have cured schizophrenia or any other mental disorder”.

“I have talked about treatment, and I’ve talked about a robust response for some individuals to the point of remission of symptoms,” he said.

In a separate interview with Scientific American, he stressed that the keto diets that some people choose to improve their general state of health and well-being are “not at all the same thing as treating a serious brain disorder like epilepsy or schizophrenia”.

“By no means would I ever want them to think that [a person with schizophrenia] can go wing it and just try a diet and cure themselves.”

Science Feedback reached out to the U.S Department of Health and Human Services for comment, and will update this review if new information becomes available.

Conclusion

While some preliminary reports suggest that the ketogenic diet can be beneficial to people with certain mental disorders, the evidence base remains highly limited. The claim that the ketogenic diet cures mental illness is unsubstantiated by the research so far. Further investigation, particularly in the form of large randomized controlled trials, are needed to establish the effectiveness and safety of the ketogenic diet as a treatment for mental illness. It is important to keep in mind that medical ketogenic diets are highly specialized and require medical supervision. People should not substitute their prescription medication with a diet change without first seeking their doctor’s advice.

References:

1. Harris et al. (2013) Schizophrenia: Metabolic aspects of aetiology, diagnosis and future treatment strategies. Psychoneuroendocrinology.
2. Roosterman and Cottrell. (2021) The two-cell model of glucose metabolism: a hypothesis of schizophrenia. Molecular Psychiatry.
3. Palmer et al. (2019) The ketogenic diet and remission of psychotic symptoms in schizophrenia: Two case studies. Schizophrenia Research.
4. Palmer CM. (2017) Ketogenic diet in the treatment of schizoaffective disorder: Two case studies. Schizophrenia Research.
5. Danan et al. (2022) The Ketogenic Diet for Refractory Mental Illness: A Retrospective Analysis of 31 Inpatients. Frontiers in Psychiatry.
6. Sethi et al. (2024) Ketogenic Diet Intervention on Metabolic and Psychiatric Health in Bipolar and Schizophrenia: A Pilot Trial. Psychiatry Research.
7. Dietch et al. (2023) Efficacy of low carbohydrate and ketogenic diets in treating mood and anxiety disorders: systematic review and implications for clinical practice. BJPsych Open.