Why it’s so hard to resist milk chocolate or a donut? This is due to the combination of sugars and fats that causes a dopamine light to light up in our brains. How exactly does this work and can we also ‘reset’ this system?
Foods high in sugar and fat actually change our brain, even if we only eat a little bit of it every now and then. The brain learns through the reward system to want to see exactly this kind of food on the plate again in the future. “There are several reasons why the Western diet is so popular among the population. When fats and sugars are processed in the body, the brain receives all kinds of stimuli via neural pathways,” explains Professor Marc Tittgemeyer. Scientias.nl. “Among other things, this ensures that the neurotransmitter dopamine is released in the midbrain.”
Bad messengers
“These dopamine signals are the messengers that allow nerve cells to communicate with each other. The dopamine system in this part of the brain is crucial for the regulation of our reward responses. When the fat and sugar signals converge in this area, they likely interact, triggering a reward response,” Tittgemeyer continues.
“Another reason why we are so attracted to foods that are high in fat and sugar is because breast milk also has these ingredients. There is hardly any food in nature that is high in sugars and fat at the same time, but breast milk is the big exception. It is our first introduction to food and at the same time it is linked to a social, affective component (affection).”
Fat pudding with a lot of sugar
The researchers from the German Max Planck Institute and the American Yale wanted to put it into practice to test whether our brain really learns to recognize fatty and sugary foods and so subconsciously encourage us in the future to eat more of this unhealthy food. They set up an experimental study in which two groups of participants were given a small pudding every day for eight weeks in addition to their normal diet. The pudding in one group consisted of a lot of sugar and a lot of fat, while the other group had little fat in the pudding. Both puddings contain the same amount of calories.
More dopamine
The reward response in the brains of the group that ate the high-fat, high-sugar pudding had increased significantly after eight weeks. Especially the dopamine system, the part of the brain responsible for motivation and reward, turned out to be extra active. The subjects in the test group had not gained more weight than the control group. The team was also unable to find any difference in blood values such as blood sugar or cholesterol levels. Still, Tittgemeyer thinks that the preference for sugary and fat-rich foods will persist among the participants after the study. “New connections have been made in the brain and they don’t disappear that quickly. In the end, the whole idea of learning something new is that you won’t soon forget it.”
Hunters and collectors
This neural system evolved at a time when we might need every calorie we could find in the future. But now this reward response is doing Western people more harm than good. “Our brain network evolved over the past hundreds of thousands of years, while food was scarce. Man was a hunter and gatherer, it took a lot of time and effort to get your food together. It was not self-evident that there was enough to eat every day.
A mechanism that allows eating more than necessary in times of abundance therefore brought an evolutionary advantage. A neural reward system in which a person is encouraged to ‘overeat’ via a hedonic drive works ideally for this. For example, energy reserves in the form of a fat layer can be built up in the ‘fat years’, so that the chance of survival is greater in the ‘lean years’.”
Fat and depressed
The physical consequences of eating sugar and fat are especially great, but serious psychological problems can also arise. “In overweight people, the metabolic system is messed up. Metabolic signals are distorted or misjudged by the body. For example, a certain degree of insulin resistance can occur, as a result of which neural reactions no longer work properly. Tolerance means that a larger dose of the stimulus hormone is required to elicit the same response. Ultimately, this can lead to all kinds of medical complaints and disorders, such as diabetes, cardiovascular disease, dementia and depression,” explains Tittgemeyer.
But is this process still reversible? “It is unclear to what extent it is possible to ‘reset’ the dopamine system and reduce the desire for fatty and sugary foods. Animal studies have shown this to be possible, but the time frame is unclear. No evidence has been found in human studies to date. In theory, a ‘reset’ would be easier to achieve in people with a healthy metabolism, while it seems very difficult in people with obesity,” concludes the professor.
