How a ‘Balanced’ Diet Can Affect Your Brain and Mental Health

  • A new study found diet patterns may impact mental health outcomes.
  • Researchers classified individuals into four diet patterns.
  • These patterns were reduced starch, vegetarian, high protein and low fiber, and balanced.

The old adage about following a balanced diet is mostly known for its positive physical benefits, but a new study suggests that such eating habits have significant effects on mental health and cognition.

A new study, published in Nature Mental Health this month, examined the food-liking patterns and dietary preferences of more than 180,000 adults in the United Kingdom and broke those patterns into four categories:

  • Starch-free or reduced starch
  • Vegetarian
  • High protein and low fiber
  • Balanced

More than half of the people surveyed fell into the “balanced” category, and their reported mental health outcomes and cognitive function were better than any of the other three.

Those who followed the high-protein/low-fiber diet had lower gray matter volumes in a part of the brain called the postcentral gyrus, which coordinates how our body moves through the environment, than those who followed a balanced diet.

Additionally, the people who were vegetarian had higher gray matter volumes in part of the brain called the thalamus and precuneus. Notably, the study found an increased risk of mental health issues in those who consumed more vegetables and fruits, a finding the authors explained could be due to the design of their study and requires further study.

Highly processed foods have been found to contribute to a wide variety of health issues, including:

Diets like the Mediterranean diet, which has an emphasis on fish and vegetables, have shown promising effects on physical health. But diets that aid in reducing inflammation can also have a significant impact on brain health and mental health, according to Molly Rapozo, RDN, Registered Dietician Nutritionist & Senior Nutrition and Health Educator at Pacific Neuroscience Institute in Santa Monica, CA, who was not involved in the study.

“Diets characterized by high intakes of antioxidant rich vegetables and fruit, limited meat consumption, and use of anti-inflammatory olive oil as a primary fat source are associated with decreased dementia risk. For instance, adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, which is high in plant-based foods and low in high-saturated fat foods, has been linked to improved cognitive function and larger brain volumes in specific regions,” Rapozo told Healthline.

Rapozo also said that diets high in saturated fats, sugars, and refined carbohydrates have been associated with decreased cognitive function and brain volume.

“The impact of diet on the gut microbiome also plays a significant role in brain health, with evidence suggesting that a healthy gut, promoted by diets rich in dietary fiber, may preserve the gut-brain axis and potentially improve cognition,” Rapozo said.

By creating balance in eating habits, the study suggests, people can lay a foundation for better mental health and cognition.

Lifestyle choices are also a significant factor, Rapozo said, citing quality sleep, regular exercise, and good stress-management techniques as essential to supplement a balanced diet.

Rapozo said the study was “exciting” in part because it was such a large study with over 181,000 participants and had a significant amount of data involved.

“It was also found that high protein, low fiber diets with an emphasis on snack foods were associated with lower well-being scores, higher levels of inflammatory markers, and an increased stroke risk. These findings appear to agree with what we already know about diet and brain health,” Rapozo said. “We can modify our diets to improve brain health by Including vegetables, fruit, starches such as whole grains, legumes, and potatoes; as well as lean protein, fatty fish, and plant fats such as nuts, seeds, avocado, olives, and olive oil. Eat less highly processed snack foods, fatty meats including bacon and sausage, sugar, and other refined carbohydrates.”

Diets like paleo, keto, and Whole 30 all focus on less of a particular nutrient, like carbohydrates, but are not intended to be followed for long periods of time, Melanie Murphy Richter, a registered dietitian nutritionist and the director of communications for the nutrition company Prolon, who was not involved in the study, told Healthline.

“A strict keto diet with little to no carbohydrates can add significant stress and inflammation to the body and cause a variety of nutritional deficiencies and potential poor health outcomes. The Whole 30 diet is actually phase one of a larger food auditioning plan for people to learn their food intolerances. Many people start and stop at Whole 30, and never go on to the actual food auditioning that it was designed to prep your body for,” Richter said. “Most people struggle to understand what ‘balanced’ means and so they aren’t aware of how to get all the nutrients they need within the parameters of these diets. But it’s possible! For vegans, prioritizing plant-based proteins like legumes, lentils, tofu, beans, nuts, seeds, and peas will help ensure they meet the proper protein criteria without animal meats or dairy. It’s also important not to use veganism as an excuse to eat loads of vegan processed foods, as many people do.”

Rapozo echoed a similar path for her clients, saying that specific diets of restriction are targeting specific goals, but that people should look at longer-term ideals for how they eat.

“Special diets are implemented to gain desired results such as weight loss, avoidance of food allergens, personal values, etc. When working with clients my goal is to help people make their meal plans as brain healthy as possible,” Rapozo said. “For instance, keto can emphasize plant fats, lean protein, and fatty fish instead of high saturated fat sources. Vegan diets can be more balanced with plant proteins from legumes, soy, nuts, and seeds. Once client goals are met, I encourage the inclusion of a greater variety of foods.”

A new study of more than 180,000 people in the UK suggests that a balanced diet, which does not restrict specific foods, is associated with better mental health and cognitive function.

By focusing less on a diet of restrictions, experts say, a better overall cognitive outcome can be made possible.

But lifestyle choices, like sleep quality, exercise, and stress management, are also important factors to mental health and cognition.