Ketogenic Diets May Improve Depression Symptoms

Ketogenic diets (KDs) may modestly improve depressive symptoms, particularly when ketosis is biochemically verified, an analysis finds.¹ However, evidence for anxiety remains inconclusive, highlighting the need for larger trials.

This systematic review and meta-analysis is published in JAMA Psychiatry.

“Greater improvements in depressive symptoms were observed with ketone monitoring, very low-carbohydrate interventions, absence of high-carbohydrate comparators, and in nonobese participants,” wrote the researchers of the study. “No consistent moderators were identified for anxiety.”

The ketogenic, or “keto,” diet is a high-fat, moderate-protein, and very low-carbohydrate eating plan that shifts the body into a state of ketosis, where fat is used for energy instead of glucose.² Originally developed in the 1920s to treat drug-resistant epilepsy, the diet restricts daily carbohydrate intake and emphasizes fats and proteins from foods like meat, fish, eggs, and low-starch vegetables. Its focus is on macronutrient composition rather than calorie restriction, and it has gained popularity for both therapeutic and weight loss purposes.

The researchers included studies evaluating KDs in adults 18 years or older, defined as consuming fewer than 26% of calories from carbohydrates or less than 50 grams per day.¹ MEDLINE, Embase, and APA PsycINFO were searched on April 18, 2025, with additional studies identified via manual searches and clinical trial registries. Eligible study designs included randomized clinical trials (RCTs), quasi-experimental studies (QSEs), cross-sectional studies, case series, and case reports that assessed psychiatric symptoms using validated scales. Data extraction was performed by 1 reviewer and independently verified by 2 others.

A total of 50 studies encompassing 41,718 participants were included. Among 10 RCTs assessing depressive symptoms, KDs were associated with a significant reduction compared with control diets (standardized mean difference [SMD], −0.48; 95% CI, −0.87 to −0.10; I² = 67.2%), with stronger effects observed in studies that verified ketosis, included nonobese participants, used very low-carbohydrate interventions, or compared against non–high-carbohydrate diets.

Nine RCTs on anxiety symptoms showed no significant effect (SMD, −0.03; 95% CI, −0.18 to 0.12; I² = 41%). In QSEs, 9 studies on depressive symptoms demonstrated consistent improvements (standardized mean change using change scores [SMCC], −0.66; 95% CI, −0.83 to −0.50; I² = 0%), while 6 studies on anxiety also reported reductions (SMCC, −0.58; 95% CI, −0.81 to −0.36; I² = 0%).

However, the researchers acknowledged this review had several limitations, which include small sample sizes, varied designs, short follow-up, and inconsistent reporting of adherence and adverse events. Additionally, heterogeneous populations and outcomes limited generalizability, and findings showed associations but not causality.

Despite these limitations, the researchers believe the findings suggest modest benefits of KDs for depression.

“Our findings in this systematic review and meta-analysis suggest that KDs may confer therapeutic benefits for depressive symptoms, whereas evidence for anxiety remains preliminary,” wrote the researchers. “Discrepancies between RCTs and QSEs likely reflect design differences and intervention fidelity. Improvements have been reported across varied populations, and adverse events were generally mild; however, these findings should not be interpreted as uniform or causal, and not all patients are likely to benefit.”

References

1. Janssen-Aguilar R, Vije T, Peera M, et al. Ketogenic diets and depression and anxiety. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2025.3261

2. Scherr R, Colorafi R, James K. Nutrition and health info sheets for health professionals—the ketogenic diet. UC Davis. Accessed November 4, 2025. https://nutrition.ucdavis.edu/outreach/nutr-health-info-sheets/pro-ketogenic-diet