“We are what we eat” – How diet impacts our brain structure

Lara Hamzehpour
About the Author

Lara Hamzehpour studies interdisciplinary neuroscience at the Dept. of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University of Frankfurt. (Germany) and works on the effects of nutrition and lifestyle on mental health.

Food has become omnipresent and plays a huge role in our everyday life. We eat when we’re hungry, as a reward after a successful work day, as a comfort when we are stressed or sad. We also sometimes eat less and exercise more when we want to lose weight. But what many people don’t know – or seem to forget – is that our brain functioning also depends on what we eat. With the research that I did for my master thesis, I found that a healthy diet and regular physical activity are associated with more grey matter in the brain, which we need for cognitive functioning. In other words: what’s good for our body is also good for our brain!

 Most of us are able to choose what we want to eat nowadays. This  has led to a growing awareness of food choices. We start considering the effects of different foods on our body and have become selective as to our diets. This has led to the basic understanding that healthy eating as well as physical exercise (together referred to as ‘healthy lifestyle’) are closely connected to an athletic body shape, good physical condition and the prevention of or recovery from various diseases.

A healthy lifestyle is however also good for our brain. In fact, the effects of healthy lifestyle on the brain, cognition and mental health have gained great importance in neuropsychiatric research lately. Numerous studies could demonstrate how diet impacts our cognitive abilities and how specific nutrients even regulate emotions or behavior [1]. As an example, the APPetite study investigates the effects of lifestyle on compulsive and impulsive behavior in people suffering from attention deficit/hyperactivity disorder, depression, individuals at risk for bipolar disorder, and healthy participants.

But when dietary habits and physical activity affect our emotions and behavior, doesn’t it seem plausible that these effects are also accompanied by structural changes in the brain? Accordingly, the purpose of my master project was to investigate the effects of dietary habits and physical activity on cerebral structure, or more precisely – on grey matter density. Grey matter density describes the concentration of brain tissue (cells and other substances) within our cortex – the brain’s outer layer which is responsible for cognitive processes. Consequently, the denser this layer, the better! My master thesis was part of the APPetite study mentioned above. In order to examine the dietary data in the context of differences in grey matter density, I recruited healthy adults from the APPetite study. By means of quantitative magnetic resonance imaging (MRI) I tried to find correlations between dietary fat intake, sugar consumption, vitamin B12 intake as well as physical activity levels and brain anatomy.

In summary, my findings could confirm that what is good for your body is also good for your brain. More specifically, I found that a higher consumption of unsaturated fatty acids compared to saturated fatty acids correlates with increased grey matter density. Just a quick reminder: unsaturated fatty acids are those found in fish, vegetable oil, nuts, seeds and avocados; saturated fats are mostly gained from animal- and dairy products [2,3] . Furthermore, I could show that a higher intake of vitamin B12, higher physical activity levels and a lower sugar consumption correlate with increased grey matter density. In more concrete terms, this means that a diet consisting of more unsaturated fatty acids compared to saturated fats, a lot of vitamin B12, but little sugar, as well as a lifestyle including high levels of physical exercise could be associated with increased grey matter density.

So what do these results tell us? Right, a healthy diet and physical exercise seem to promote the increase of our brain density (or more precisely our grey matter density) in some cortical areas, meaning that there is more tissue available for cognitive processes. And this might eventually make us smarter. So – instead of watching Netflix all day, eating crisps and chocolate – we should supersize our brains by riding the bike instead of taking the bus, going for the salmon instead of the Schnitzel, choosing the apple over the ice cream and the whole grain pasta with vegetables over the mac & cheese. Finally, apart from the fact that we will stay fit and healthy, another positive “side”-effect will be that a healthy lifestyle additionally reduces our risk to experience cognitive decline and neurodegeneration when we get older [4] . So what else are we waiting for?!

Read also this blog about measuring daily diet and physical activity using apps: https://newbrainnutrition.com/how-we-measure-behavior-outside-of-the-laboratory/


  1. Spencer, Sarah; Layé, Sophie; Shukitt-Hale, Barbara; Barrientos, Ruth (2017): Food for thought. How nutrition impacts cognition and emotion. In: npj Science of Food 1. DOI: 10.1038/s41538-017-0008-y.
  2. Crupi, Rosalia; Marino, Angela; Cuzzocrea, Salvatore (2013): n-3 Fatty Acids. Role in Neurogenesis and Neuroplasticity. In: Current medicinal chemistry 20. DOI: 10.2174/09298673113209990140.
  3. Patterson, Emma; Wärnberg, Julia; Kearney, John; Sjostrom, Michael (2010): Sources of saturated fat and sucrose in the diets of Swedish children and adolescents in the European Youth Heart Study. Strategies for improving intakes. In: Public health nutrition 13, S. 1955–1964. DOI: 10.1017/S1368980010001266.
  4. Poulose, Shibu M.; Miller, Marshall G.; Scott, Tammy; Shukitt-Hale, Barbara (2017): Nutritional Factors Affecting Adult Neurogenesis and Cognitive Function. In: Advances in nutrition (Bethesda, Md.) 8 (6), S. 804–811. DOI: 10.3945/an.117.016261.