A ketogenic, low-carbohydrate diet may help alleviate symptoms of schizophrenia and depression, according to new research from St. Michael’s Hospital in Toronto, published in JAMA Psychiatry. The diet, however, showed no significant impact on anxiety disorders.
The researchers reviewed 50 studies encompassing more than 41,000 adults across 15 countries. Participants included individuals with psychiatric conditions — schizophrenia, major depressive disorder, bipolar disorder, generalized anxiety disorder, and PTSD — as well as people without mental health diagnoses, including those with obesity. Mental health outcomes were measured using validated clinical scales.
The ketogenic diet, characterized by high fat, moderate protein, and very low carbohydrate intake, is traditionally used to treat drug-resistant epilepsy. It shifts the brain’s energy source from glucose to ketone bodies, influencing mitochondrial function, inflammation, oxidative stress, and neurotransmitter signaling.
Study findings indicated that participants following the ketogenic diet experienced a moderate reduction in depressive symptoms. No consistent benefits were observed for anxiety disorders, and further subgroup analyses did not identify factors that enhanced anxiety symptom improvement.
The diet also appeared to reduce psychotic symptoms and stabilize mood in individuals with schizophrenia or bipolar-spectrum disorders.
The authors suggest that ketogenic nutrition could serve as a supplementary approach in mental health treatment, particularly when biochemical ketosis is maintained. They note, however, that long-term clinical studies are needed to confirm the mechanisms behind these effects.
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