We often have the reflex to snack on something sweet to fight hunger and fatigue. But we should opt for a protein snack instead, because amino acids, nutrients from proteins, stimulate certain regions of the brain involved in alertness and energy balance in the body.
Everything we eat is finely analyzed by the brain which integrates information on the nature of these foods as well as the amount of energy they contain. In addition to making it possible to detect the taste of food, and therefore what is good or not, this “high command” function is particularly essential for controlling appetite and body weight: in fact, as soon as the levels of As energy returns to normal during the meal, a range of regulatory mechanisms kick in to inform the brain of the situation. This responds immediately by reducing the appetite so as to finish the meal and thus avoid ingesting excess energy which can lead to excess weight.
While the brain’s ability to respond to variations in the body’s energy levels is well known, the impact of different nutrients on this response remains enigmatic. However, this is an important subject because in our daily life, the content of our plates cannot be considered as being only a source of energy: each meal consists of a complex mixture of carbohydrates, lipids and proteins which, in in addition to providing the energy essential to the functioning of the body, can have several impacts on cell function. In other words, even with equal calories, are there differences between a meal rich in sugar or protein?
The brain prefers protein
To measure the effect of a mixture of nutrients on brain function, researchers fed animals a mixture of amino acids (similar to that found in egg whites), sugar or a combination of these nutrients. Three hours later, they measured the activity of neurons that use a neurotransmitter called orexin, these cells present in the hypothalamus of the brain being well known to be involved in the energy balance of the body as well as in vigilance.
They observed that the administration of the mixture of amino acids caused a significant increase in the electrical functioning of orexin neurons compared to control animals, which had not received the mixture of amino acids. Completely opposite, the animals fed with a source of sugar saw their cerebral activity decrease compared to the controls. It is therefore not surprising that we feel a certain drowsiness a few hours after a meal rich in sugar! The researchers observed, however, that when the sugar was administered together with the amino acids, the activity of the neurons using the orexin still remained high, suggesting that the brain is able to discriminate between the two substances and responds preferentially to the presence of amino acids.
To avoid the stroke of the pump: a piece of cheese, nuts and no candy
These results are in line with numerous studies which show that meals rich in protein (and therefore in amino acids) can increase the feeling of satiety and make people more alert than a starch-based meal. It is also interesting to note that in several cultures around the world, particularly in Asia, the traditional breakfast contains several sources of protein and little sugar, an ideal combination to activate the neurons involved in awakening and start the day. on the right foot. The same situation applies at work: if you feel tired in the afternoon, avoid soft drinks or sugary treats and instead favor a piece of cheese or a handful of nuts. It’s much better for your health… and your concentration!
Kamani et al. Activation of central orexin/hypocretin neurons by dietary amino acids. Neuron; 72: 616-629.