The Study
Ketogenic diet is less effective in ameliorating depression and anxiety in obesity than Mediterranean diet: A pilot study for exploring the GUT-brain axis.
This study found that people who ate the Mediterranean diet felt less sad than those on the keto diet, but it wasn't a big or perfect test. It also gave mouse poop from people to mice and saw the mice got anxious — which is interesting, but doesn't prove the same thing happens in humans.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists tested two diets — one high-fat (keto) and one plant-based (Mediterranean) — on people with obesity to see how they affect mood and behavior, then tested the gut bacteria from these people in mice.
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 556 / 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.
- 1Yes — the difference in depression improvement (32% vs.
- 214%) is meaningful and suggests diet choice can strongly impact mood in obese adults.
- 3The Mediterranean diet made people 32% less depressed; keto made them 14% less depressed but reduced impulsive behavior.
- 4Mice given keto gut bacteria became anxious and had higher brain levels of taurine, alanine, and betaine.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Brain, behavior, and immunity
Year
2025
Authors
Virginia Mela, Nadia Suyin Ortiz Samur, Akshay Kumar Vijaya, V. Gálvez, M. García-Martín, Borja Bandera, J. I. Martínez-Montoro, A. M. Gómez-Pérez, I. Moreno-Indias, Francisco J Tinahones
Related Content
Claims (7)
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.
Among obese adults aged 18–65, following a Mediterranean diet for three months leads to a 32% reduction in depression scores, while a ketogenic diet leads to a 14% reduction.
Obese adults who follow a ketogenic diet for three months show lower impulsivity on the urgency subscale compared to those who follow a Mediterranean diet, which shows no change in impulsivity.
Transplanting gut bacteria from obese humans on a ketogenic diet into healthy mice causes those mice to display behaviors associated with anxiety and increases levels of taurine, alanine, and betaine in their brains.
Obese individuals on a ketogenic diet have different gut bacteria than those on a Mediterranean diet, and these differences are linked to different patterns of behavior and metabolism in humans and mice.
In obese adults, following a ketogenic diet is linked to higher levels of taurine, alanine, and betaine in the brain, and changes in threonine levels are linked to changes in behavior.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.