The Study
A Ketogenic Diet for Treatment-Resistant Depression
This study is like a fair test where two groups of people with serious depression tried different diets. One group ate very low-carb food, and the other ate more veggies and healthy fats. The low-carb group felt a little better after 6 weeks, but not by much—and after 12 weeks, both groups felt the same. So we can't say the low-carb diet definitely caused the improvement.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists tested if a strict low-carb diet (ketogenic diet) helps people with depression that didn't improve with medicine, compared to a healthy plant-based diet.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 572 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1A 2-point drop on the PHQ-9 scale is small — it’s not enough to feel dramatically better for most people, and it didn’t last.
- 2After 6 weeks, people on the low-carb diet felt slightly better (PHQ-9 score dropped 2.2 points more than the other group).
- 3But after 12 weeks, both groups felt the same.
- 4The better mood only happened in people with very severe depression (score ≥20), and it had nothing to do with ketones in their urine.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
JAMA Psychiatry
Year
2026
Authors
Min Gao, Megan Kirk, Heather Knight, Eva Lash, M. Michalopoulou, N. Guess, Richard Stevens, Michael Browning, Scott Weich, P. Burnet, Susan A. Jebb, P. Aveyard
Related Content
Claims (8)
Studies that account for other factors show that the mood improvement from ketogenic diets is about 75% smaller than what is reported in studies that do not control for those factors.
In adults with treatment-resistant depression, a very low-carbohydrate ketogenic diet with intensive dietary support is linked to a small decrease in depression symptoms after 6 weeks compared to a diet rich in plant compounds, but this improvement does not last to 12 weeks and is not related to the level of ketones in the body.
In people with treatment-resistant depression, a ketogenic diet does not lead to better depression outcomes than a control diet after 12 weeks, compared to the initial improvement seen at 6 weeks.
For people with treatment-resistant depression, a ketogenic diet reduces depression symptoms more in those with severe symptoms (PHQ-9 ≥20) than in those with moderate symptoms (PHQ-9 15–19), with an average difference of 4.73 points after 6 weeks.
In adults with treatment-resistant depression who follow a ketogenic diet, the amount of ketones detected in urine does not change along with changes in depression symptoms, meaning ketosis is not the mechanism behind any mood improvement.
For people with treatment-resistant depression, a ketogenic diet does not lead to better outcomes in anxiety, thinking skills, pleasure, overall well-being, or social and work performance compared to a similar control diet. The only benefit observed is a reduction in depression symptoms.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.