What Causes Overweight Children: Genetics or Environment? - dummies

What Causes Overweight Children: Genetics or Environment?

By Jane Kirby, The American Dietetic Association

Children become overweight due to genetic tendencies, lack of physical activity, unhealthy dietary habits, or a combination of these factors. In some rare cases, an endocrine disorder is to blame. Your pediatrician can perform an exam and blood test to rule out this possibility or to design a treatment program if needed.

Sometimes, the apple doesn’t fall far from the tree. If a parent or sibling is overweight, chances are that the child will be, too. The odds of a child becoming overweight increase dramatically if both parents are overweight.

In a series of studies on twins, researchers found that the likelihood of becoming fat is estimated to be between 65 and 75 percent if you have a family history of obesity. (For comparison, the genetic risk for breast cancer is about 45 percent.)

Researchers found that when identical twins were placed in separate adoptive homes, the twins’ bodies looked more like each other’s and those of their biological parents than the bodies of their adoptive parents — the homes in which they were raised.

More recent work on twins shows that twins often share similar metabolic rates, eating styles, and food preferences, too, even when they’re raised separately. Some experts have criticized the twin studies for assuming that all environmental conditions are the same, which may or may not be true.

Genes alone don’t sentence a child to a life of obesity. Many experts think that the way a child is raised is even more important. If nature is the genetic pool that humans swim in, then nurture is the location of that pool and the way it’s maintained.

Ethnic background, geographical location, and socioeconomic status may influence weight. In fact, contrary to the twin studies, many genetic experts argue that the inherited component of weight is much closer to 30 percent on average, compared to the 65 to 75 percent chance purported by the researchers who studied the twins.

It’s crystal clear that a lack of physical activity leads to excess weight in both children and adults. Interesting is the correlation between the amount of time that a child watches television and his weight. The more TV that a child watches, the heavier he is.

Experts think that this phenomenon is twofold. First and foremost, while children watch TV, they’re inactive, and therefore, burning few calories. Second, commercials often encourage consumption of high-calorie foods — and eating too many of them, of course, can result in weight gain. This also can be true for kids who spend plenty of time at the computer.