Activity and Obesity
We have discussed that net body weight is the sum of two opposing forces, calories in and calories burned. If a person eats more than he or she burns up through basal metabolism and additional activities, there is weight gain. Of course, for growing children it is okay to gain weight, but it should be appropriate for the gain in height. Anyway, it should be clear to you by now that a person’s activity level can have a profound effect on his weight. With genetic influences already in place, the only mechanisms to lose weight or to maintain an appropriate weight, independent of drugs and/or surgery, are related to activity and calories.
There is no doubt that steadily decreasing amounts of activity contribute to the obesity upsurge in the U.S. Why has this happened? The answer is a multifactorial one but a major contributor is technology; many tasks that in the past required intense physical labor now are performed by machines. How many farmers weed their crops by hand? How many people walk to the shopping mall and to the grocery store? How many people mow their own lawns? Of those that do, how many use a manual “push” mower? You get the point; we are an affluent people and we are good at getting other people or machines to do much of what used to be physical activity for each of us. Many of us do try to conmpensate by going to a gym or jogging, or whatever, but the statistics show that very few people have regular exercise programs long-term that amount to much in the way of caloric expeniture.
What about the children?
It’s particularly worrisome for the children. Computers and television have largely replaced outdoor play after school. In the school setting, things are as bad; most schools have cut back drastically on physical education programs because of funding formulas that favor academic classes. The five-day-a week physical education programs that used to be standard in the schools are rare indeed; many high school students have phycical education classes only as an optional activity. Certainly many students do participate in organized school sports and in non-school sponsored sports such as community baseball leagues, but fewer and fewer children are getting much exercise. What is very important to understand is that it’s not a question of children getting no exercise, but rather, less exercise than in the past.
The situation is particulary bad for teenage girls. Studies have shown that girls participate in exercise activities less and less beginning at about age 14 years; by age 18 years, fewer than 20% of girls get any meaningful physical activity on a regular basis (unless you consider turning a key to start a car and holding a cell phone to one’s ear as meaningful exercise).
- Obesity: The Thrifty Gene Theory
- Obesity: Calories