Researchers tested whether a ketogenic diet (very low in carbohydrates) could help people with depression that didn’t respond to standard treatments. In this study of 88 adults, both the ketogenic diet group and a control group eating more vegetables showed improvement in depression symptoms over 6 weeks. The ketogenic diet group improved slightly more, but the difference was small. While the results are promising, scientists say we need more research to understand if this diet truly helps depression or if other factors—like getting professional support and paying attention to what you eat—are what really matter.

The Quick Take

  • What they studied: Does eating a very low-carbohydrate diet (ketogenic diet) help people with depression that hasn’t improved with medication?
  • Who participated: 88 adults aged 18-65 years (mostly women) from across the UK who had depression that didn’t respond well to standard treatments. All participants had moderate to severe depression symptoms at the start.
  • Key finding: After 6 weeks, people on the ketogenic diet showed slightly more improvement in depression symptoms compared to those eating a healthier regular diet with more vegetables. However, the difference was small—about 2 points on a 27-point depression scale—and by week 12, the difference nearly disappeared.
  • What it means for you: A ketogenic diet may offer modest additional benefits for depression, but it’s not a replacement for medical treatment. The improvement might also come from simply paying attention to your diet and getting professional support. Talk to your doctor before making major dietary changes, especially if you’re managing depression.

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of research. Researchers randomly assigned 88 people with treatment-resistant depression into two equal groups. One group followed a ketogenic diet (eating less than 30 grams of carbohydrates per day—roughly equivalent to one slice of bread) for 6 weeks with weekly support from a dietitian. The other group ate a regular healthy diet with extra vegetables and fruits, plus healthier fats, also with weekly dietitian support.

Both groups received the same amount of professional attention and support, which is important because it helps researchers know that any differences come from the diet itself, not from getting more help. The study measured depression symptoms at the start, after 6 weeks, and again at 12 weeks to see if improvements lasted.

This study design is important because previous evidence about ketogenic diets and depression came mostly from small case reports or animal studies, which are less reliable. A randomized controlled trial with a matched control group (both groups getting equal support) helps prove whether the diet itself actually works, rather than just the placebo effect or the benefit of getting professional attention.

This study has several strengths: it was published in a top medical journal (JAMA Psychiatry), used a proper control group that also received professional support, and measured outcomes at multiple time points. However, the sample size was relatively small (88 people), and most participants were women, so results may not apply equally to men. The study only lasted 12 weeks, so we don’t know about long-term effects. Additionally, the improvement in the control group was nearly as large as in the ketogenic diet group, suggesting that other factors may be equally important.

What the Results Show

Both groups showed significant improvement in depression symptoms over the first 6 weeks. The ketogenic diet group’s depression score dropped by an average of 10.5 points, while the control group’s dropped by 8.3 points on a 27-point scale. This means the ketogenic diet group improved about 2.2 points more than the control group—a statistically significant but small difference.

At the 12-week follow-up, the gap between groups narrowed even further. The ketogenic diet group’s advantage shrank to just 1.85 points, and this difference was no longer statistically significant. This suggests that the extra benefit from the ketogenic diet may not last beyond the initial 6-week period.

Importantly, both groups experienced meaningful improvement. In the ketogenic diet group, about 27% of people experienced depression remission (significant improvement), compared to about 18% in the control group. However, this difference was not large enough to be statistically significant.

The researchers also measured anxiety, loss of interest in activities (anhedonia), thinking problems, and quality of life. There were no meaningful differences between the two groups in any of these areas. This suggests that while the ketogenic diet may help with depression symptoms specifically, it doesn’t appear to offer additional benefits for related mental health concerns or overall functioning.

This is the first large, well-controlled study of ketogenic diet for treatment-resistant depression in humans. Previous research was limited to small case reports and animal studies, which suggested the diet might help. This trial provides more reliable evidence, but the modest effect size suggests that earlier enthusiasm may have been overstated. The finding that a healthy control diet also produced substantial improvement aligns with existing research showing that dietary improvements in general can support mental health.

Several important limitations should be considered: First, the study only included 88 people, which is a relatively small sample. Second, 69% of participants were women, so we can’t be sure the results apply equally to men. Third, the study only lasted 12 weeks, so we don’t know if benefits continue longer or if people can stick with the ketogenic diet long-term. Fourth, the control diet was quite healthy and involved professional support, making it a strong comparison rather than a ‘do nothing’ control. Finally, the improvement in the control group was nearly as large as in the ketogenic diet group, making it unclear whether the ketogenic diet itself is special or whether any structured dietary improvement with professional support helps depression.

The Bottom Line

If you have depression that hasn’t responded to standard treatments, a ketogenic diet may offer modest additional benefits, but it should not replace medical care or medication. Consider discussing this approach with your doctor and a registered dietitian before starting. The evidence suggests a moderate level of confidence for a small benefit, but it’s not a proven treatment. A healthy diet with professional support appears to be helpful regardless of whether it’s ketogenic or not.

This research is most relevant to adults with treatment-resistant depression who are looking for additional strategies to try alongside medical treatment. It may be worth considering if you’ve already tried standard treatments without adequate improvement. However, this is not recommended as a first-line treatment or as a replacement for medication and therapy. People with certain medical conditions (like diabetes or heart disease) should be especially cautious about ketogenic diets and should consult their doctor first.

Based on this study, if a ketogenic diet is going to help, you might expect to see some improvement within 4-6 weeks. However, the improvement appears modest and may not be substantially better than simply eating a healthier diet with professional support. It typically takes several weeks for dietary changes to affect mood and mental health, so patience is important.

Want to Apply This Research?

  • Track your depression symptoms using a simple daily mood scale (1-10) and weekly depression screening questions (like the PHQ-9). Also log what you eat to monitor carbohydrate intake if trying a ketogenic diet. This helps you see patterns between diet and mood over time.
  • If interested in trying this approach, start by working with a dietitian to gradually reduce carbohydrates while maintaining balanced nutrition. Use the app to set weekly goals (like reaching under 30g carbs per day) and track adherence. More importantly, use the app to maintain regular check-ins with your healthcare provider about depression symptoms and medication.
  • Establish a baseline depression score before making dietary changes. Then measure weekly for the first 6 weeks to see if you notice improvement. Continue monthly measurements for at least 3 months to determine if benefits persist. Also track energy levels, sleep quality, and anxiety, as these often change alongside mood. Share this data with your doctor to inform treatment decisions.

This research describes a clinical trial studying ketogenic diet for treatment-resistant depression. The findings suggest modest benefits, but this should not be considered a proven treatment for depression. Depression is a serious medical condition that requires professional care. Do not use dietary changes as a replacement for medication, therapy, or other medical treatments prescribed by your doctor. Before starting a ketogenic diet, especially if you have depression, diabetes, heart disease, or take medications, consult with your healthcare provider and a registered dietitian. If you are experiencing suicidal thoughts or severe depression symptoms, seek immediate professional help. This summary is for educational purposes and should not be used for self-diagnosis or self-treatment.