Can Keto Help Treatment-Resistant Depression? What a New RCT Found

TL;DR

A JAMA Psychiatry RCT found that a ketogenic diet significantly reduced depression symptoms compared to a control diet in patients with treatment-resistant depression. After 6 weeks, keto participants saw a 10.5-point drop in PHQ-9 scores versus 8.3 in controls — a modest but meaningful effect in patients whom medications had failed.

For the roughly 30% of depression patients whose symptoms don’t respond to standard medications, treatment options have been limited. Now, a rigorous clinical trial published in JAMA Psychiatry suggests that changing what you eat might help where pills haven’t.

The Study: What They Did

Researchers at the University of Oxford recruited 88 adults with treatment-resistant depression — people who had tried at least two antidepressant medications without adequate response.

📚 Treatment-Resistant Depression (TRD)

Depression that doesn’t respond adequately to at least two different antidepressant treatments at adequate doses and durations. It affects an estimated 10-30% of people with major depression.

Participants were randomly assigned to one of two groups:

Ketogenic diet group: Prepared meals providing less than 30g carbs per day, plus weekly dietitian support
Control group: A “phytochemical” diet emphasizing vegetables, fruits, and unsaturated fats, with equal dietitian support

Both groups received the same level of professional guidance — the only difference was the diet itself. This design helps isolate whether it’s truly the keto aspect that matters, not just the attention and support.

The Results: What Changed

After 6 weeks, both groups improved substantially — but the keto group improved more:

📊 Depression Scores (PHQ-9, Lower = Better)

Keto group: ↓ 10.5 points
Control group: ↓ 8.3 points
Difference: 2.18 points favoring keto
Effect size: Cohen’s d = 0.68 (medium effect)

The between-group difference reached statistical significance (P = 0.05). To put that effect size in context: a Cohen’s d of 0.68 is larger than what many antidepressant medications achieve in clinical trials.

Why Might This Work?

The researchers didn’t investigate mechanisms directly, but there are several theories:

Brain Fuel

Ketones cross the blood-brain barrier and serve as an alternative fuel source for neurons. Some researchers hypothesize that certain depressed individuals may have impaired glucose metabolism in the brain, and ketones could bypass this bottleneck.

Inflammation

Ketogenic diets have documented anti-inflammatory effects. Since inflammation has been linked to depression in multiple studies, reducing systemic inflammation might improve mood.

GABA and Glutamate

Ketosis appears to shift the balance between GABA (calming neurotransmitter) and glutamate (excitatory neurotransmitter) in favor of GABA — similar to how some anti-seizure medications work.

📚 The Epilepsy Connection

Ketogenic diets have been used to treat epilepsy since the 1920s. The brain mechanisms that reduce seizures may overlap with those that affect mood. Several psychiatric medications, including some used for bipolar disorder, were originally developed as anti-seizure drugs.

What This Doesn’t Mean

⚠️ Important Caveats

This is one study with 88 people over 6 weeks
The control group also improved significantly
We don’t know if effects persist long-term
Keto isn’t a replacement for psychiatric care
If you’re on medication, don’t stop without consulting your doctor

The researchers themselves note that “the clinical relevance is uncertain, as the mean effect size compared with the control was modest and not evident in secondary analyses.”

In other words: promising, but not a miracle cure.

The Bigger Picture

This trial is part of a growing field called metabolic psychiatry — the idea that mental health conditions may have metabolic roots, and that metabolic interventions (like diet) could complement or sometimes replace pharmaceutical ones.

"Preclinical evidence and case reports suggest potential therapeutic benefits of ketogenic diets in the treatment of depression, but evidence from well-controlled randomized clinical trials has been lacking."

— Kirk et al., JAMA Psychiatry 2026

What makes this study notable isn’t just the positive result — it’s that it was done rigorously. JAMA Psychiatry is one of the top psychiatric journals in the world. The study was randomized, controlled, and pre-registered.

Practical Takeaways

If you’re struggling with depression, especially if standard treatments haven’t worked well:

🎯 What to Consider

Talk to your doctor before making major dietary changes, especially if you’re on medication
A trial period of 4-6 weeks seems reasonable based on this research
Track your mood — subjective feelings matter, but data helps
Electrolytes matter — keto flu can mimic or worsen depression symptoms if you’re not getting enough sodium, potassium, and magnesium
Don’t go it alone — the study participants had weekly dietitian support

Diet alone probably isn’t the answer for everyone. But for some people — especially those whom medications haven’t helped — it might be worth trying alongside other treatments.

The Bottom Line

A well-designed clinical trial found that ketogenic diets can reduce depression symptoms in people who haven’t responded to medications. The effect was modest but real, and importantly, there were no serious adverse events.

Is this proof that keto cures depression? No. Is it evidence that metabolic approaches to mental health deserve more attention? Absolutely.

The researchers are planning longer follow-up studies. In the meantime, if you’re interested in trying this approach, work with healthcare providers who can monitor your progress and adjust your care accordingly.

This article is for informational purposes only and is not medical advice. If you’re experiencing depression, please consult a qualified healthcare provider.