Efficacy of low carbohydrate and ketogenic diets in treating mood and anxiety disorders: systematic review and implications for clinical practice.
Level 4 - case-series / case-control
Systematic review comprised exclusively of case reports, cohort studies, and uncontrolled observational studies without randomized trials
PubMed 37066662 · doi:10.1192/bjo.2023.36
What was done
A systematic review and narrative synthesis (PROSPERO CRD42019116367) searching MEDLINE, Embase, PsycINFO, and Cochrane databases from inception to September 6, 2022. Eligible studies evaluated adults (aged 19 to 75 years) with mood or anxiety disorders receiving low-carbohydrate or ketogenic dietary interventions with reported mood or anxiety outcomes.
What was found
Out of 1,377 identified articles, 12 heterogeneous studies totaling 389 participants were included (diet duration: 2 weeks to 3 years). The included evidence comprised 9 case reports, 2 cohort studies, and 1 observational study, with zero randomized controlled trials. Studies suggested potential efficacy in bipolar disorder, schizoaffective disorder, and depression/anxiety, with reported relapse after diet discontinuation in some patients. No pooled numerical effect sizes or quantitative results were reported in the abstract due to variable data quality and non-systematic reporting of efficacy, ketosis levels, carbohydrate intake, adverse effects, and discontinuation rates.
Why it matters
This review clarifies that despite growing clinical interest, evidence supporting ketogenic interventions for mood and anxiety disorders rests almost entirely on uncontrolled and anecdotal reports rather than controlled trials.
Limits
No randomized controlled trials were identified. The evidence base is dominated by individual case reports (9 of 12 studies), with incomplete dietary adherence tracking, inconsistent biochemical confirmation of ketosis, and unstandardized recording of adverse events and dropout rates.