Start Here: What Is Metabolic Psychiatry?

Reading time: about 4 minutes. General education only, not medical advice.

The short version

Metabolic psychiatry is a young field that asks a simple question: what if how our bodies make and use energy plays a part in mental illness?

Your brain is small, but it is hungry. It uses about a fifth of the body's energy. If the systems that turn food into fuel aren't working well, it makes sense that the brain might feel it. Researchers are now testing whether improving metabolic health can also help mental health.

Mental illness and metabolism often show up together

Doctors have long noticed that people with serious mental illnesses, like schizophrenia, bipolar disorder and major depression, are more likely to have problems like high blood sugar, insulin resistance, high blood pressure, high triglycerides and extra weight around the belly. Some of this comes from medications, stress, poverty and lifestyle. But researchers think part of it may be linked to the illness itself.

A 2025 review in BJPsych Advances describes metabolic problems as more common in people with severe mental illness than in the general public, and says they lead to more sickness and earlier death. The authors also support using the term "metabolic psychiatry" to raise awareness of this overlap (Cambridge Core, 2025).

A few key words, made simple

• Metabolism: all the ways your body turns food into energy and building blocks.
• Insulin: a hormone that helps move sugar from your blood into your cells.
• Insulin resistance: when cells stop listening to insulin well, so the body has to make more of it. It often comes before type 2 diabetes. The same 2025 review notes studies linking insulin resistance to a harder course of illness in bipolar disorder and to worse symptoms in schizophrenia. It also warns that we don't yet know which one causes which.
• Mitochondria: tiny parts inside cells that make most of their energy. Think of them as power plants.
• Ketones: a fuel the body makes from fat when carbohydrate intake is very low. The brain can use ketones as well as sugar.
• Ketogenic diet: a very low-carb, higher-fat way of eating that pushes the body to make ketones. It has been used under medical care for epilepsy for about a hundred years.

The "brain energy" idea

Some researchers argue that metabolic problems are not just side issues, but may be part of the root cause of some mental illnesses. A 2025 commentary in BJPsych Advances describes this "brain energy theory," which puts poorly working mitochondria at the center of both metabolic and mental illness (Beyond comorbidities, 2025).

Other research looks for clues in genes. A 2025 study in Annals of General Psychiatry found that a genetic marker of mitochondrial function was linked to the risk of bipolar disorder, depressive symptoms and some other brain conditions (Fu et al., 2025). This kind of study suggests a link. It does not prove that fixing mitochondria will treat anyone.

What have diet studies found so far?

Most of the work so far is small and early, but interesting:

• Stanford pilot study (2024): 21 adults with schizophrenia or bipolar disorder, who also had metabolic problems, followed a ketogenic diet for four months while staying on their usual medication. Many people's metabolic health got better, and on average, psychiatric symptom scores improved too (Sethi et al., Psychiatry Research; Stanford Medicine news).
• Edinburgh pilot study (2025): 27 people with bipolar disorder who were stable at the start tried a modified ketogenic diet for 6–8 weeks. People lost weight and their blood pressure dropped. Mood scores did not change overall, but on days when people had higher ketone levels, they tended to report better mood and energy, and less anxiety and impulsivity (Campbell et al., BJPsych Open, 2025).

Both studies had no comparison group and were small. That means the results could be due to chance, extra support, or people's hopes. Larger randomized trials, where people are assigned by chance to different diets, are now under way. These include a Stanford trial in schizophrenia, bipolar disorder and depression (ClinicalTrials.gov NCT06748950) and a McLean Hospital trial in first-episode bipolar disorder (NCT06221852).

What this does not mean

• It does not mean mental illness is "just" a diet problem. Genes, trauma, sleep, stress, relationships and much more all matter.
• It does not mean you should stop or change your medication. Stopping psychiatric medication suddenly can be dangerous.
• A ketogenic diet is a real medical treatment with possible side effects. It can change how some medications work, including lithium and diabetes and blood pressure drugs. Anyone thinking about it should do it with their own clinician, and ideally a dietitian with ketogenic experience.

As Stanford's Dr. Shebani Sethi put it in a 2025 interview, more research is needed to show clearly whether this works and why (Stanford Medicine, 2025).

Where to go next

• Read our simple research write-ups.
• Ask a general question.

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