A ketogenic diet may hold therapeutic promise for people with serious mental illness (SMI) such as such as schizophrenia or bipolar disorder—but the existing data are very sparse, according to a meta-analysis published in Translational Psychiatry.However, there is decent evidence that ketogenic diets are associated with modest cognitive benefits in people with dementia or other neurodegenerative conditions.
Why It’s Relevant
Ketogenic dietary interventions—which manipulate the body to use molecules called ketone bodies instead of glucose as energy—have been used to treat epilepsy for a century. Their potential use for other brain disorders was thrust into the spotlight this past February when HHS Secretary Robert F. Kennedy Jr., claimed that the ketogenic diet could “cure schizophrenia.” But what does the available body of data say?
By the Numbers
- Researchers compiled data from 73 studies—ranging from individual case reports to randomized clinical trials—exploring the therapeutic potential of a ketogenic diet for SMI (n=31) or neurocognitive disorders (n=42).
- Overall, most SMI studies reported that maintaining a ketogenic diet reduced the severity of symptoms such as psychosis, mania, or depression, but these were primarily case studies and retrospective analyses.
- The one randomized SMI trial assessed did not find a difference between a ketogenic diet and a plant-forward diet for treatment-resistant depression.
- Based on data from 14 clinical trials, a ketogenic diet was superior to placebo at improving or preserving cognitive performance (effect size of 0.24); improvements were more pronounced among individuals with mild cognitive impairment versus those with dementia.
The Other Side
As noted, many of the included studies—particularly for SMI—relied on small sample sizes, and publication of preliminary data may be biased toward positive results. The 73 studies also varied in terms of participant characteristics and specific dietary interventions (e.g., in some instances, regular diets were simply supplemented with ketone-promoting fatty acids), which may make true comparisons difficult.
Takeaway Message
The potential of ketogenic diets in the treatment of SMI or cognitive impairment is real for some patients, but adequately sized clinical trials are needed to establish their effectiveness and side effects across different psychiatric disorders.
Related Information
Source
Kateryna Maksyutynska, et al. The efficacy of ketogenic interventions on neuropsychological & metabolic outcomes in serious mental illness & neurocognitive disorders: a systematic review & meta-analysis. Translational Psychiatry. Published August 27, 2026. doi:10.1038/s41398-026-04370-2
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