Why does stress make women eat?
Alexey Petrov, "Newspaper.Ru" based on the materials of Yerkes National Primate Research Center of Emory UniversityResearchers from the Robert Yerkes National Primate Research Center at Emory University have found that female rhesus monkeys, who are in a subordinate position in the primate community, consume much more high-calorie food compared to dominant females.
Scientists believe that their discovery may be key to understanding the physiological background of the sharp increase in the number of obese people in the United States in all age groups, starting in the mid-seventies. For many specialists, this study will also be interesting from a methodological point of view, since the work of scientists published in the latest issue of Physiology and Behavior (Mark E. Wilson et al., Quantifying food intake in socially housed monkeys: Social status effects on caloric consumption) describes a way to reliably and automatically account for food consumed by animals.
The relationship between diet, psychological stress, social factors and environmental factors is very complex. That is why Mark Wilson, head of the physiology department of the scientific center, put the work on primate individuals who are under constant psychological pressure from others. He and his team studied the diet of female rhesus monkeys leading a social lifestyle.
Their colonies are always built according to a hierarchical principle – some individuals are always in a subordinate position in relation to a higher group, and this applies to both males and females. Such an organization imposes constant stress on the oppressed class of monkeys, but makes the entire colony more stable in relation to external threats.
Wilson's experiment consisted of several cycles, each of which lasted 21 days. During this time, the monkeys were offered a choice of a diet of sweet foods, some of which were low-calorie, others contained a lot of fat. After 21 days, standard food returned to the diet. To track the intensity and quality of primate nutrition, scientists were helped by an automated computer system that activated the distribution of a particular food using microchips implanted in macaques under the skin in the wrist area.
It turned out that macaques in a socially oppressed position consumed large quantities of both types of food – both fatty and low-calorie, and they did it for 24 hours.
The dominant females consumed significantly less food and limited their meal time only to daylight hours.
As it is easy to guess, the voracious oppressed monkeys gained weight much faster, and their hormonal balance was shifted towards fat derivatives. According to Wilson, these changes in the body of monkeys can significantly affect the metabolism of animals and lead to the accumulation of a large amount of fatty tissue.
The scientist is sure that female rhesus macaques, due to their position in society, are predisposed to the development of obesity, since due to constant stress they prefer a fatty diet, and their body has an increased concentration of the hormone cortisol. Perhaps because of these factors, there is a redistribution of fats into the internal cavities of the body. Something similar is observed in the organisms of some diabetics.
Of course, it is premature to pull any theory on Wilson's results, and scientists are aware of this, because the next stage of work will involve a tomographic study of the brain activity of dominant and oppressed monkeys. Perhaps their overeating also has a certain neurochemical aspect, so the centers of satisfaction and pleasure in the dominant class and the subordinate may be different.
Whether it is possible to conclude from this work that the vast majority of the population of the United States, which is considered to be quite democratic, is in a socially oppressed position, further experiments will also show.
Portal "Eternal youth" www.vechnayamolodost.ru15.05.2008