The Study
Association between dietary ketogenic ratio and depressive symptoms: A population-based cross-sectional study using 2007-2018 NHANES data.
This study looked at a big group of people and found that those who ate more fat and protein and less carbs tended to report feeling less sad. But it didn't watch them over time, so we don't know if eating that way made them feel better, or if people who felt sad just ate differently.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists looked at what people ate and how they felt and found that people who ate more fat and protein relative to carbs tended to feel less sad.
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 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — even after accounting for age, income, and health, people with higher DKR scores were much less likely to have depression symptoms, suggesting diet patterns may matter for mood.
- 2For every 1-point increase in a special diet score (DKR), people were 87% less likely to have symptoms of depression.
- 3Body shape (ABSI) helped explain 11% of this benefit, but fatness (BMI, waist size) made it worse.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of affective disorders
Year
2025
Authors
Xiaoyin Zhuang, Yanni Zhan, Xia Feng, Chaoyuan Liu
Related Content
Claims (5)
A higher ketogenic diet ratio is linked to lower depressive symptoms, and this link is partly explained by body shape index (ABSI), which reduces the association by 11.03%, while BMI and waist circumference increase the association by 11.43–14.69%.
Changes in diet that increase ketone production are not linked to changes in depression through the measured inflammatory markers, as these markers showed no statistically significant role in connecting diet to mood.
People who follow diets with a higher ketogenic ratio show a consistent statistical link to depressive symptoms, regardless of their sex, race, education level, marital status, or lifestyle habits.
In U.S. adults, a higher dietary ketogenic ratio is associated with lower odds of experiencing depressive symptoms measured by the PHQ-9 scale, with each one-unit increase in the ratio corresponding to an 87% reduction in odds.
A measurable dietary metric called the dietary ketogenic ratio correlates with lower levels of depressive symptoms, and it provides more consistent data than self-reported dietary records in studies linking diet and mood.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.