Ketogenic Diet and Treatment-Resistant Depression
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Reviewed & Translated by Dat Tien Nguyen, B.A, ScM.
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Posted on March 18th, 2026
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The ketogenic diet, characterized by high fat and very low carbohydrate intake, induces sustained production of ketone bodies that influence metabolic pathways, inflammatory signaling, and neurotransmission. Given its neurobiological effects, interest has grown in evaluating its potential role in psychiatric disorders. A recent study published in the Journal of the American Medical Association examined whether a ketogenic diet could improve outcomes in patients with treatment-resistant depression.
Funding Source(s): Oxford Health Biomedical Research Centre
The clinical study enrolled 88 adults diagnosed with major depressive disorder. At baseline, 52% were receiving selective serotonin reuptake inhibitors, 27% were treated with serotonin–norepinephrine reuptake inhibitors, and 14% were using tetracyclic antidepressants. Despite pharmacologic therapy, participants continued to experience moderately severe depressive symptoms, with a mean baseline Patient Health Questionnaire-9 (PHQ-9) score of 19.5, where a maximum score of 27 indicates the most severe symptom burden.
Participants were randomly assigned to follow either a control phytochemical-rich diet or a ketogenic diet. The control diet emphasized increased fruit and vegetable intake and replacement of saturated animal fats with unsaturated plant-based oils. The ketogenic diet restricted carbohydrate intake to less than 30 grams per day, with 15% to 20% of total daily energy derived from protein.
After six weeks of intervention, there was no statistically significant difference in depression severity between the ketogenic and control diet groups. Secondary analyses similarly showed no meaningful differences in associated symptom domains, including anxiety, anhedonia, or cognitive impairment. These findings suggest that short-term adherence to a ketogenic diet does not confer additional benefit over a balanced, plant-forward dietary approach in patients with treatment-resistant depression.
Funding Source(s): Oxford Health Biomedical Research Centre
The clinical study enrolled 88 adults diagnosed with major depressive disorder. At baseline, 52% were receiving selective serotonin reuptake inhibitors, 27% were treated with serotonin–norepinephrine reuptake inhibitors, and 14% were using tetracyclic antidepressants. Despite pharmacologic therapy, participants continued to experience moderately severe depressive symptoms, with a mean baseline Patient Health Questionnaire-9 (PHQ-9) score of 19.5, where a maximum score of 27 indicates the most severe symptom burden.
Participants were randomly assigned to follow either a control phytochemical-rich diet or a ketogenic diet. The control diet emphasized increased fruit and vegetable intake and replacement of saturated animal fats with unsaturated plant-based oils. The ketogenic diet restricted carbohydrate intake to less than 30 grams per day, with 15% to 20% of total daily energy derived from protein.
After six weeks of intervention, there was no statistically significant difference in depression severity between the ketogenic and control diet groups. Secondary analyses similarly showed no meaningful differences in associated symptom domains, including anxiety, anhedonia, or cognitive impairment. These findings suggest that short-term adherence to a ketogenic diet does not confer additional benefit over a balanced, plant-forward dietary approach in patients with treatment-resistant depression.