I just finished reading through this paper on agression and the metabolic syndrome. This has to be one of the most unique studies I've ever seen. The authors believe that the metabolic syndrome is caused by a lack of aggression in modern society. They hypothesize that the lowered need for aggression in modern society is evolutionary novel, and that it "turns on" the metabolic syndrome.
It is explained in the paper as so:
"In animal societies subordinate individuals generally have a lower social status. Patches of richer food are more likely to be snatched by dominant individuals leaving the subordinate ones with less calorie rich food. Since subordinate individuals are likely to have less as well as insecure access to food, they need to develop a ‘‘thrifty” metabolism and indulge in binge eating. Social subordination is shown to induce high fat intake and weight gain in animals and this would be adaptive for individuals who have only occasional access to rich food.
Unlike ‘doves’ in animal societies, ‘diplomats’ in modern human societies can have higher social status and continued access to calorie rich food. The high calorie availability for physically weak and inactive individuals poses a paradox that is characteristically human and more typical of modern lifestyle."
To test their hypothesis, they put participants in a camp where they participated in "a series of physical exercises, activities and games that involve neuro-motor actions characteristic of Stone Age hunting or combat." The study didn't lead to any weight loss, but it did lead to reduced inflammation and improved glycemic control.
Interesting!






