Research in Review: Ketogenic Diets, Depression, & Anxiety

A research paper on the impact of ketogenic diets on depression and anxiety came out earlier this month. There’s so much misinformation out there about diets and mental health, so let’s talk about this diet and unpack the study’s findings.

What’s a ketogenic diet?

A ketogenic diet is a low-carbohydrate, high-fat diet that aims to put someone in ketosis.

So, what’s ketosis?

To answer this, let’s start with what’s typical for bodies. Typically, glucose is the main source of energy for the body, including the brain. Glucose, which is often referred to as blood sugar, is made when carbohydrates are broken down. When you significantly restrict carbohydrates, your body needs to find a new source of energy.

Enter fats! Fatty acids are made when fats are digested. If glucose levels are low and fatty acid levels are high, the body will turn fatty acids into something called ketone bodies to use for energy. When the body is in a state in which it’s breaking down fat for energy instead of carbohydrates, it’s said to be in ketosis.

In short, when following a ketogenic diet, you eat lots of fat and restrict carbohydrates so that your body creates ketone bodies as the main source of energy instead of glucose.

People can get very excited about the idea of breaking down fat for energy. While this sounds like a pro, there are also many cons to understand about this diet.

Importantly, achieving and staying in ketosis requires a strict and well-planned diet. The body prefers to use glucose for energy, so you will quickly come out of ketosis if you don’t follow the diet strictly. And it isn’t just carbohydrates and fats that matter! Even eating too much protein can bring you out of ketosis.

The diet also needs to be well-designed because, if you aren’t careful, this type of restrictive, high-fat diet can cause nutrient deficiencies, put a strain on the liver and gall bladder, and lead to poor heart health.

What’s the connection between a ketogenic diet and medicine?

Although a ketogenic diet has gotten a lot of attention (positive and negative!) in the wellness space over the last several years, it’s actually not new in medicine. A ketogenic diet was introduced as a non-medication treatment for epilepsy in the 1920s. Now, it’s most commonly used for children with epilepsy that aren’t responding well to medication alone.

So, why try ketogenic diets in mental health care?

There’s some overlap between epilepsy and mental disorders like bipolar disorder, schizophrenia, and major depressive disorder. All of these conditions have been associated with issues with metabolism and the way different types of brain cells interact (particularly excitatory, brain cells that increase brain cell communication, and inhibitory, brain cells that decrease brain cell communication).

Although most of the current excitement over ketogenic diets in mental health care is for schizophrenia and bipolar disorder, ketogenic diets have also been looked at in depression and anxiety disorders.

What study?

The recently published paper was a systematic review and meta-analysis of the current studies on this topic.

A systematic review is a research method that finds, puts together, and evaluates all of the current studies on a topic. A meta-analysis takes this a step further by adding a statistical layer so that you can see the actual overall result when combining the studies all together. By gathering information from multiple independent studies, a meta-analysis allows for a more complex and reliable analysis than each individual study alone.

Although meta-analyses are considered the gold standard of research evidence, it’s important to note that they are limited by how good the studies they include are. When a meta-analysis is done on large, randomized controlled trials (RCTs), this is as good as evidence can get in the research world. When a meta-analysis is done on smaller, not randomized trials, it’s still better than each smaller study alone, but it will still have limitations because the available research is limited. Because there aren’t that many RCTs on ketogenic diet in depression and anxiety currently, this meta-analysis looked at both RCTs as well as other study types. 

What did the study find?

This study found that ketogenic diets were associated with a small to moderate improvement in depressive symptoms across RCTs as well as other types of studies. It found no impact on ketogenic diets on anxiety symptoms in RCTs, but a small to moderate impact when looking at other study types.

When it came to depression, the ketogenic diet seemed to have a bigger impact when ketone monitoring was done. Ketone monitoring confirms the presence of ketones and reassures the diet is being followed strictly enough. This may indicate the diet does have an effect when done correctly; however, there are other explanations for this benefit, including better counseling on the diet and increased time with a clinician in those groups.

For depression, there was also a larger impact on diet type in patients without obesity when compared to patients with obesity. This may be because ketosis is typically more easily achieved in people without obesity.

The most common adverse effects reported related to the ketogenic diet included constipation, fatigue, headache, nausea, and diarrhea.

What are the study’s limitations?

As mentioned above, the quality of a meta-analysis is limited by the quality of the studies available. Some of the studies used were of mediocre quality and susceptible to bias, so that must be considered when evaluating the results.

Also, the best types of studies “blind” people to the intervention so they don’t know what group they are in. This helps prevent people from getting a “placebo effect,” which means they feel improvement just because they think they are getting an active intervention.

It’s also hard to know how much these results can be generalized because there were a wide range of results (some studies showed a larger benefit than others, and, even within studies, there were big differences in impact seen). These big differences could be related to the fact that there were all different types of low-carbohydrate, high-fat diets used, sometimes they monitored for ketosis and sometimes relied on self-report, and diet counseling and support wasn’t always offered.

Importantly, not all studies included people with clinical depression or anxiety. Over half of the studies were people with subclinical symptoms (meaning they experienced some symptoms of depression and/or anxiety, but did not meet criteria for the full disorders).

Lastly, the studies included did not compare ketogenic diets to other effective treatments. So, even if a ketogenic diet offers some relief from symptoms of depression or anxiety, it doesn’t mean it works any better, or even equally, to currently available interventions.

Can you just give me a “one-liner”?

The most accurate “one-liner” on this study would be ketogenic diets were associated with some improvement in some people with some symptoms of depression and anxiety (but not necessarily a full disorder).

What’s the bottom line?

The bottom line is that ketogenic diets for depression and anxiety are still being researched. Based on this study, it’s unclear if ketogenic diets would be effective clinically, or just something that could be used in the wellness space for people without disorders wanting to improve mild symptoms. Existing research seems to suggest it’s more promising for depressive symptoms than anxious, and promising enough that we should do additional and better studies.

It would be helpful to have a large-scale RCT that uses a consistent diet, monitoring of ketosis, and dietary support. If a large-scale RCT confirms a ketogenic diet is helpful for depression and/or anxiety, additional studies would be needed to determine how it compares to other diets, like the Mediterranean diet, which is easier to follow and also has evidence in mental health care. It’s also important to compare these diets to other known treatments for these disorders, like psychotherapy and medication.

No matter what, at this point in time, if you discuss ketogenic diets with your mental health care provider, it should be considered an experimental option because the evidence is still evolving, and there’s need for stronger studies. It’s also important to keep in mind that ketogenic diets can be extremely difficult to follow consistently and can have negative health impacts when not well-planned. This is not an experimental treatment you should try on your own. If you are interested in seeing its impact on your mental health, you should talk to your physician.

Reference:

Janssen-Aguilar R, Vije T, Peera M, et al. Ketogenic Diets and Depression and Anxiety: A Systematic Review and Meta-Analysis. JAMA Psychiatry. Published online November 05, 2025. doi:10.1001/jamapsychiatry.2025.3261