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Can genes cause obesity in men?

How did we get so fat? “Obviously there’s a genetic component to obesity, “ says Barbara Rolls, PhD. Rolls holds the Helen A. Guthrie Chair in Nutritional Sciences at Pennsylvania State University. “But,” she adds, “the surge in obesity clearly can’t be due to genetic changes. We don’t evolve that quickly.”

That said, when it comes to getting fat, not all men are created equal. The genetic differences are clear from studies conducted by Claude Bouchard, PhD, of the Pennington Biomedical Research Center at Louisiana State University. Controlled portions of food were given over 100 days to sets of identical twins. While weight gain was similar for each pair of twins, it varied dramatically among the pairs. Some sets of twins gained as few as eight pounds during the “overfeeding” experiment, while others put on as much as 26 pounds.

We all know a few men who can quaff and stuff it all in their wooden legs and still weigh what they did in college. Some people are more predisposed to gain more weight than others, and research indicates that gaining weight rapidly as an infant is associated with a higher risk of adult obesity.

“We don’t know whether the weight gain in infancy is a cause of obesity, or whether they are both controlled by the same gene or perhaps by cultural practices,” says Nicolas Stettler, MD, MSCE, a professor of pediatrics at the University of Pennsylvania. But it may well be that some of us developed metabolic patterns in infancy that continue to influence our eating habits throughout life.

But genes don’t explain the increase in obesity. “I think we can safely say that at the end of the day, the cause of obesity is eating more than you need for your physical activity,” says Stettler. “We eat more, and the availability of more sedentary entertainment leads people to be more sedentary.”

Bigger portions breed bigger appetites which can lead to obesity

Men eat 70% more at a sitting than women do, Rolls tells WebMD. But, she says, men are “the primordial eating machines.” They tend to listen to their bodies more while women eat what they think they are supposed to eat.

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