Cambridge University researchers have discovered that proteins, and not sugar, keep us awake and stimulate the consumption of calories.
All started from the observation that the administration of glucose tends to inhibit the activity of a specific substance, orexin, resulting in postprandial somnolence.
Thus proteins would be able to block the inhibitory action that glucose has on brain cells that produce orexin (also known as hypocretin), a substance that regulates wakefulness and calorie consumption. A reduction in the activity of these cells can lead to narcolepsy which not coincidentally is also related to weight gain. The finding suggests that, to be efficient during the day, it is better to have a protein snack rather than a sugar-based snack. The result of this study was published in the “Neuron” journal, volume 72, issue 4, pgs. 616-629, 17 November 2011.
Thus not only the amount of calories one eats in a diet, but also their provenance. According to the research it has been suggested that also the quality of the nutrients present in one’s diet can alter the levels of orexin. To this end guinea pigs were administered various mixtures of amino acids, while recording cellular responses. The researchers have discovered that amino acids mixtures that correspond to the contents of the egg albumen are able to stimulate the neurons that release orexin to a higher degree than any other nutrients. This action would occur by blocking the inhibitory activity of glucose on orexin cells. These results would explain why protein meals tend to make one more vigilant in regard to meals with carbohydrates. “What is interesting is that we have a way to tune the brain cells to a state of greater or lesser activity in deciding what we eat,” observed Burdakov Denis, who led the research. “Not all brain cells are activated in a trivial way by all nutrients, the composition of the diet is essential. To combat obesity and insomnia in today’s society, we need more information on how diet affects cells that regulate sleep and appetite. For the moment, research suggests that if we can choose between jam on toast and albumen on toast, it is better to opt for the latter! Although both contain the same number of calories, a little protein will cause the body to burn more calories than one consumes.”