Obesity

The Pimas, Native Americans, who live in Arizona, have one of the highest rates of obesity in the world. But it is remarkable to see pictures of Pimas from many years ago, when they first came into closer contact with white Americans. They were thin! The Pimas thrived in harsh desert conditions, where it is more of a challenge to gain sufficient calories and nutrients than in fertile green lands. We can imagine that, during times of famine, those who did not have the most efficient bodies for living on a minimum of calories might perish. Also, those who tended to conserve calories through lower levels of activity might be more likely survive.



Fast forward to today. In the developed countries, we live in a sea of easily available calories, and labor saving devices, transportation, televison, video games, and computers abound. Bodies best able to cope with famine are now at the greatest risk for obesity and all its attendant health problems. The answer to being overweight or obese is to take in fewer calories (diet)and be more physically active (exercise). It is difficult to live on fewer calories and to strive to be more physically active than the natural set point for the body (behavior modification).

See the following links at this site:
Weight loss
Physical activity
Changing habits

See also the link to the (United States) National Institutes of Health publication:
The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. This contains an authoritative approach from leading experts in the field.

Also, see this body mass index (BMI) calculator.
Overweight: BMI of 25 to 29.9 (kg/meter squared)
Obesity: BMI of 30 or more (kg/meter squared)

Also see the following links to other sites:
Physical activity from the Weight-control Information Network, a service of the National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health;
Physical Activity Facts from the National Coalition for Promoting Physical Activity;
Guide to Physical Activity, which provides information on calories burned in various activities;