Why are we always attracted to what is fatty and sweet rather than what would be better for our health? If we know what’s healthy for us, it’s still another thing when we have to give up a cake in favor of an apple! Researchers have managed to explain why and it is at the level of our brain.
In most western countries, we eat too much fat and too much sugar. The link between too rich a diet and being overweight is direct. For example, in France, one in two adults is overweight! More worryingly, one in three children is already overweight. What exactly are the underlying mechanisms? A team is interested in the effects of our diet on our brain. Their results were published in the journal Cell Metabolism.
Obesity and dopamine
It is well documented that obesity is accompanied by impaired dopaminergic function in the brain. Dopamine is a neurotransmitter that allows the transmission of information between neurons. It is often called the neuromediator of happiness: it is involved in motor control, sleep, learning but also pleasure and motivation.
Dopamine is a key component of the reward system. When an action gives pleasure, dopamine is released. This is what makes us want to reproduce the action that gave us pleasure. This mechanism is involved in the onset of addiction and this is why it is so difficult to quit tobacco or drugs.
Pre-existing or secondary alteration?
The authors were particularly interested in one question in particular. Did obese people have impaired dopaminergic function prior to becoming overweight, such as individual susceptibility to weight gain? Or did obese people experience a decline in dopaminergic function as they gained weight and were exposed to an unbalanced diet?
To answer this, a randomized controlled study was conducted. Participants, of normal weight, received in addition to their usual diet: either a snack high in fat and sugar (in the form of a cake), or a snack low in fat and sugar. The experiment lasted eight weeks. The results of the study show that daily exposure to fat and sugar decreased the desire of these people for foods low in fat and sugar. Impaired dopaminergic function was observed independent of changes in body weight.
So it’s not really our fault that we still prefer fatty and sugary foods! On the other hand, knowing this, we can choose to modify our reflexes. The less we eat of this type of product, the less our brain will ask for it! It’s hard at first but then it takes a lot less effort.
