Ketogenic diet reduces stress and improves mental health, researchers say

The keto diet is high in fat, low in carbohydrates, and moderate in protein. This diet is recognized for its potential metabolic and psychological benefits.

A recent pilot study from Stanford Medicine also reported improvement in symptoms in patients with severe mental illness after four months of a keto diet and standard treatment. Based on these findings, a new study further examines the diet's potential psychological benefits for the general public.

A new study examined how the keto diet affects various aspects of mental health in the general global population.

Results published in Nutrition suggest that following a keto diet may be associated with better mental and emotional health in the general population, with benefits increasing over time.

How does the keto diet affect mental health?

Researchers from Northumbria University in Newcastle upon Tyne, England, sought to find out how the keto diet may affect various aspects of mental health, including:

• mood (calmness, satisfaction, cheerfulness)
• cognitive and emotional stress
• symptoms of depression and anxiety
• feeling lonely

Researchers compared self-reported mental health outcomes of people following the keto diet with those following other diets, using data from two online surveys.

The study authors recruited participants through social media for two cohorts:

• 2021 cohort - 147 participants
• 2022 cohort - 276 participants

All participants were over 18 years of age and free of clinically diagnosed mood, anxiety, neurodevelopmental, or neurodegenerative disorders.

The first cohort responded to surveys that included the Bond-Lader Visual Analog Mood Scales and the Perceived Stress Scale, while the second cohort completed surveys that included the Depression, Anxiety and Stress Scale and the Revised UCLA Loneliness Scale.

Both cohorts were asked the same demographic, socioeconomic and health-related questions, and dietary habits, collected using a weekly 45-item food frequency questionnaire.

To determine ketogenic dietary patterns in the cohorts, foods were classified based on their compatibility with the ketogenic diet:

• Ketogenic: meat, poultry, fish and seafood, some dairy products, eggs, tofu, tempeh, nuts, most vegetables, tea and coffee.
• Allowed on a ketogenic diet: fruits (fresh or frozen), most fruit juices, zucchini, low-calorie or diet drinks, some meat substitutes, cottage cheese and dairy or non-dairy spreads.
• Incompatible with the ketogenic diet: fruits in syrup or dried, grains, potatoes, beans and legumes, sweet snacks and drinks, chips and salty snacks, low-fat and flavored yogurts, breaded or fried meats, poultry and fish.
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The surveys also asked participants if they followed a ketogenic diet, their main reasons for doing so, whether they measured their ketone levels and, if so, what their most recent reading was.

People who reported following a ketogenic diet had to follow it for at least a week to be considered ketogenic diet followers in the final analysis. Those who said they were not following a ketogenic diet were simply grouped as "other diets."

Keto diet reduces stress, anxiety and depression

The survey results identified 220 participants following the ketogenic diet in two cohorts. Their main motivations for adopting the ketogenic diet were overall health and weight loss.

Remarkably, over 70% of participants did not track their ketone levels, leaving their actual ketosis status largely unconfirmed.

In the first cohort, the mean body mass index (BMI) was classified as overweight among both ketogenic diet followers and those following other diets.

However, followers of the ketogenic diet had a significantly higher BMI than those on other diets, were older, and were more likely to have high blood pressure.

The second cohort had similar age-related patterns, but there was no significant difference in blood pressure or BMI between dietary groups.

Both cohorts reported better mental well-being among ketogenic diet followers, including:

• excellent mood (calmness, contentment, cheerfulness)
• reducing anxiety and depression
• less feelings of stress and loneliness

However, reported feelings of loneliness were not statistically significant after adjusting for differences between groups.

These psychological benefits occurred regardless of ketone levels, suggesting that sustainable dietary habits may promote mental well-being independent of metabolic changes.

Participants followed the ketogenic diet for an average of 24 months in the first cohort and 44 months in the second.

The study authors noted that, unlike previous studies, longer adherence to the ketogenic diet was correlated with improved mood.

How does the keto diet support your mood and well-being?

Jasmine Savneh, MD, a board-certified psychiatrist who was not involved in the study, explained how the ketogenic diet can improve psychological well-being.

She noted that diet can increase gamma-aminobutyric acid (GABA) levels, promoting calm and relaxation, similar to the effects of benzodiazepines, drugs used to treat a variety of conditions, including anxiety.

The ketogenic diet can also affect neurotransmitters such as dopamine and serotonin, which regulate mood, and the gut microbiome, which influences behavior and the response to stress, Savne explained.

However, she emphasized: “Future studies could benefit from including biological markers to complement self-reported data, particularly in relation to levels of neurotransmitters, stress hormones such as cortisol, and gut microbiome composition.”

Kieran Campbell, a registered dietitian nutritionist with a background in psychology who was not involved in the study, agreed that more research is needed into the long-term effects of the ketogenic diet on mental health.

She noted that “some studies do not show long-term benefits for mood or cognition,” which contradicts the current study's findings that benefits increase over time.

Additionally, she noted that research on cortisol levels during the ketogenic diet remains uncertain.

Dietary approaches to improve mental health

Before attempting a ketogenic diet, Savneh emphasized the importance of consulting with medical professionals, “especially for those with complex health problems or who are considering significant dietary changes.”

"Although this diet shows evidence of mental health benefits, we are not yet at the point to safely recommend the ketogenic diet for mood disorders or for improving mental health in the general population," Campbell said.

Instead, a balanced, plant-based diet based on whole foods is recommended. Both Savne and Campbell recommend the Mediterranean or DASH diets, which have more documented mental health benefits and fewer associated risks.

For people with mental disorders, "[these diets] may be recommended in combination with traditional psychiatric treatments," Savneh said.

Limiting some ultra-processed foods and consuming healthy carbohydrates and omega-3 fatty acids can further improve mood and support mental health, Campbell concluded.