Ketogenic diet reduces stress and improves mental health, say researchers

The keto diet is characterized by high fat, low carbohydrate, and moderate protein intake. This diet is recognized for its potential metabolic and psychological benefits.

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

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

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

How does the keto diet affect mental health?

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

• mood (calm, contentment, cheerfulness)
• cognitive and emotional stress
• symptoms of depression and anxiety
• feeling of loneliness

The 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 had no clinically diagnosed mood, anxiety, neurodevelopmental or neurodegenerative disorders.

The first cohort responded to surveys that included the Bond-Lader Visual Analog Mood Scale 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, as well as dietary habits collected using a weekly 45-item food frequency questionnaire.

To determine ketogenic dietary patterns in 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 the ketogenic diet: fruits (fresh or frozen), most fruit juices, squash, 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, sugary snacks and drinks, chips and salty snacks, low-fat and flavored yogurts, breaded or fried meat, poultry and fish.

The surveys also asked participants whether they follow a ketogenic diet, their main reasons for doing so, whether they measure 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 dieters in the final analysis. Those who said they did not follow a ketogenic diet were simply grouped as "other diets."

The Keto Diet Reduces Stress, Anxiety, and Depression

The survey results revealed 220 participants following a ketogenic diet in two cohorts. Their primary motivations for adopting a 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 average body mass index (BMI) was classified as overweight among both ketogenic diet followers and those on other diets.

However, ketogenic diet followers had 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 patterns, but there was no significant difference in blood pressure or BMI between diet groups.

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

• excellent mood (calm, contentment, cheerfulness)
• reduction of anxiety and depression
• less stress and loneliness

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

These psychological benefits occurred regardless of ketone levels, suggesting that sustainable dietary habits can 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 associated with improved mood.

How Does the Keto Diet Support Mood and Well-Being?

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

The ketogenic diet may also affect neurotransmitters like dopamine and serotonin, which regulate mood, and the gut microbiome, which influences behavior and stress response, Savne explained.

However, she stressed: "Future studies could benefit from including biological markers to complement self-reported data, particularly regarding neurotransmitter levels, 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 show no 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 inconclusive.

Dietary approaches to improving mental health

Before attempting a ketogenic diet, Savne stressed the importance of consulting with a health care professional, "especially for those with complex health issues or considering significant dietary changes."

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

Instead, a balanced, plant-based, whole-foods diet 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," Savne said.

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