Simone Demmel is a psychology student at the Dept. of Psychiatry, Psychosomatic Medicine and Psychotherapy at the Goethe University of Frankfurt and studies the reciprocal effects between stress and nutrition.
In times of stress, there are mainly two eating patterns in which people react: some tend to eat less, some eat more [1]. The latter then, unfortunately, develop a desire for more salty, sweet and fatty foods, leading to negative health consequences such as weight gain [2] which in turn may influence their mental health.
But why does this happen? What is the science behind this?
The brain controls our body functions and continuously adapts to new situations. For the survival of humans, it is essential that the brain is sufficiently energized at all times. Under stress, the brain needs more energy than under normal circumstances leading the brain to act in a selfish manner. The selfish brain theory by the German scientist Achim Peters describes the relationship between the brain’s energy requirement and food intake [3]: according to this concept, the brain is given a priority role in the hierarchy of energy metabolism. Therefore, the brain takes care of itself first and claims the energy it needs from the body. The brain pull mechanism is the underlying instrument to request the energy needed, by limiting glucose flow into muscle and fat tissue, so that glucose is primarily available to the brain. If the body can’t provide the necessary energy immediately, the brain forces us to eat. And this results in eating the above-mentioned food. It delivers quickly available glucose to the brain.
Why do some people react to stress by eating more and others by eating less?
Stress responsiveness is thought to be related to different adaptation processes. Exposure to long term stressors may lead to an increased adaptation, reducing the ability of the brain pull mechanism to draw the energy needed directly from the body, thus producing the need to eat. Not adapting to stress and keeping your stress response high will probably lead to less eating.
Why does the brain eat first?
The privileged role of the brain can be explained by the evolutionary past. In life-threatening situations, highest attention was required to react quickly. So, our body has a mechanism to keep our brain functioning: It is assigned a priority role so it can continuously fill its energy needs in order to protect us from possible dangers. It is proven that during inanition the mass of the brain remains constant compared to other organs, which lose about 40% of their mass.
So, what can help us not to eat in an unfavorable manner under stress?
Since everyday stress can hardly be avoided, it is advisable to eliminate temptations and avoid snacking, such as donuts, pizza or any kind of energy-dense foods. For example, in the office: make sure that healthy food is available and prefer fresh unprocessed food, like moderate portions of berries, bananas, nuts (walnuts, almonds), dried fruits (e.g. figs) or perhaps a non-sweetened granola bar. Nuts contain good omega 3 fatty acids and are good for your nerve cells. When stressed, 5-6 small meals spread throughout the day help to keep the energy level constant. In the office a good lunch could be a mixed salad with chicken breast stripes. Take a break and eat mindfully. Try not to eat hastily, the loss of time spent eating will be rewarded by being able to concentrate better. Drinking lots of water or green tea and avoiding too much coffee and sugared soft drinks will help to prevent a lack of concentration. Water is a healthy way to regulate thirst and has absolutely no calories.