Archeological evidence of our human ancestors, observations of eating behavior in modern hunter-gatherer tribes, the anatomy of our digestive system and current neuro-scientific research suggest that humans may have a hard-wired preference for high-fat and high-calorie foods.  The available data lead scientists to estimate that ancient humans consumed more than half of their calories as meat, preferably large game.  Before the development of agriculture, some 10,000 years ago, ancient hunter-gatherer tribes of 25 or so members moved to different geographic locations to follow their food sources.  As one area became depleted of food, they moved to a new area.  This, as well as seasonal variation in the availability of food, must have resulted in periods of food plenty and scarcity.  It was in this unstable food environment that our “survival of the fittest” eating behaviors evolved.  One theory suggests that there would have been greater survival advantage to humans who consumed as much animal fat and carbohydrates as possible whenever possible, regardless of how hungry they may have been at the moment.  Those who had fattened up in periods of plenty would have been more likely to survive the periods of scarcity.

Combined with research showing that animals eat larger quantities and gain more weight when highly palatable food is easily available, our evolution-imposed food preferences may contribute to the current obesity epidemic:  we have easy access to tasty high-fat and high-calorie foods in combination with hard-wired preferences to consume these foods with abandon whenever they are available.  In addition, neuro-imaging studies show that, in some people, the brain reward areas are more highly activated when they are presented with high-calorie foods, perhaps suggesting one mechanism underlying differences among people in the ability to “resist” high-calorie foods.

To read more about this topic, check out this article:  The Modern Obesity Epidemic, Ancestral Hunter-Gatherers and the Sensory/Reward Control of Food


We live in a social world that considers sleep a luxury.  A growing body of research indicates that we hold onto this attitude at our own peril.  Sunlight exposure and night-time darkness set our body’s internal clock; social demands and temptations set our social clock.  When the two are out of sync, particularly when sleep time is chronically insufficient, metabolic chaos ensues.  Even just getting a few hours per night less sleep than needed (e.g., 6 hours a night) is associated with obesity.  For example, a study published in 2011 found that healthy men and women who were experimentally restricted to four hours per night of sleep for six nights ate significantly more than others who had a full sleep.  Moreover, they consumed more calories from fat and did not compensate for it by using more calories in activity.

To read an article on this topic:

%d bloggers like this: