The Ketogenic Diet and Mental Health: What We Know So Far

Key takeaways

• The ketogenic diet is a proven medical diet for some types of epilepsy. Its use in mental health is still being researched.
• Small studies in depression, bipolar disorder and schizophrenia show encouraging results.
• There is no high-quality evidence yet. Larger controlled trials are needed.
• Keto can affect medicines such as lithium, valproate and some diabetes drugs.
• Do not stop medication or start keto without your clinician.

What is the ketogenic diet?

The ketogenic ("keto") diet is very low in carbohydrates, moderate in protein and high in fat. In research, carbs are often kept to about 20 grams a day or a small share of daily calories.

When carbs are this low, the liver turns fat into ketones. Ketones become a fuel for the body and brain. This state is called ketosis. People can check ketone levels with a blood or breath meter.

Keto is not the same as just "eating healthier." It is a strict diet that changes how the body runs.

Why would keto affect mental health?

Doctors have used keto to treat hard-to-control epilepsy for about a century. Seizure medicines and psychiatric medicines sometimes overlap. That made researchers wonder if keto might affect mood and thinking too.

There are several theories. Ketones may give brain cells a steady fuel. Keto may lower insulin resistance and inflammation. It may change brain chemical balance. These ideas are plausible but not proven in mental illness.

There is also a simple point. Many people with serious mental illness have metabolic problems. A 2015 review found about one in three people with schizophrenia, bipolar disorder or major depression had metabolic syndrome (2015, World Psychiatry). Keto can improve some of these measures.

Can the ketogenic diet help depression?

Maybe, for some people. But the evidence is limited.

In a French hospital, 31 adults with hard-to-treat depression, bipolar disorder or schizoaffective disorder were given a ketogenic diet with their usual care. Three stopped early. In the rest, average depression scores fell sharply (2022, Frontiers in Psychiatry). But there was no comparison group, and patients were also getting hospital care.

It is worth knowing that a different, less strict diet has been tested more rigorously. In the SMILES randomized trial, adults with depression who got Mediterranean-style diet support improved more than those who got social support (2017, BMC Medicine). That was not keto, but it shows diet can matter.

Can the ketogenic diet help bipolar disorder?

Early studies suggest it may help some people. Two case reports described women with bipolar II who stayed in ketosis for years and felt more stable (2013, Neurocase). A Scottish pilot found that most people with bipolar disorder could reach and stay in ketosis for 6 to 8 weeks, with mostly mild side effects (2023, BJPsych Open). That pilot tested whether a trial was doable. It did not test whether keto works.

Can the ketogenic diet help schizophrenia?

A Stanford pilot followed 23 adults with schizophrenia or bipolar disorder and metabolic problems for four months on keto. They kept taking their medicines. People with schizophrenia saw a 32% average drop on a psychiatric rating scale. Metabolic health also improved, with no one meeting metabolic syndrome criteria at the end (2024, Psychiatry Research). Again, there was no control group.

What about anxiety, ADHD or autism?

Research here is even earlier. A 2023 systematic review looked at low-carb and keto diets for mood and anxiety disorders. It found only 12 studies, mostly case reports, and no high-quality evidence. There were some hints of benefit for bipolar disorder, schizoaffective disorder and possibly depression or anxiety (2023, BJPsych Open). We did not find strong studies to summarize for ADHD or autism in this guide.

What are the risks and side effects?

Common early side effects include tiredness, headache, constipation and hunger. These were the kinds of minor events seen in the Scottish pilot.

More serious concerns:

• Medicine interactions. Lithium levels can change as salt and water balance shifts. Diet therapies have been linked to lower valproate levels in people with epilepsy (2017, Journal of Clinical Pharmacy and Therapeutics).
• Diabetes medicines. In the Scottish pilot, one person on an SGLT2 inhibitor developed ketoacidosis, a serious condition.
• Relapse after stopping. The 2023 review noted some people relapsed when they stopped the diet.
• Not for everyone. People with certain medical conditions, eating disorders or who are pregnant need special care.

How should someone approach keto for mental health?

With a team. That usually means a prescriber, and ideally a dietitian who knows keto. They can check labs, watch medicine levels and adjust plans. Keep taking your medicine unless your clinician says otherwise.

FAQ

Is keto a cure for mental illness?
No. It is being studied as an add-on to usual care. No study shows it cures any psychiatric disorder.

How long does it take to see effects?
We don't know for sure. Studies have run from weeks to months.

Can I just eat low-carb instead?
Possibly, but research hasn't sorted out whether full ketosis is needed. The 2023 review named this as an open question.

Is it safe to try keto on my own if I take psychiatric medicine?
No. Keto can change medicine levels. Plan it with your clinician.

This article is general education, not medical advice. Talk with your own clinician before changing diet or treatment.