When you eat more calories than you use through activity, you gain weight. As simple as it sounds, you can’t assume that everyone who’s fat overeats. Being overweight stems from the interaction of several factors.
Genes play a part in how your body balances calories and energy. Children whose parents are obese tend to be overweight too. A family history of obesity increases you chances of becoming obese by about 25 to 30 percent.
Heredity doesn’t destine you to be fat. But by influencing the amount of body fat and fat distribution, genes can make you more susceptible to gaining weight.
Your body shape, for example, generally falls into one of three categories – ectomorph, endomorph or mesomorph.
The slight frames of ectomorphs reflect a low capacity for fat storage. Endomorphs have the most fat-storage capacity. And mesomorphs have an ability to store fat that falls somewhere in between. Fat storage is also more evenly distributed.
If you’re a rounded endomorph you may never have the lean body of an ectomorph or the muscular build of the mesomorph regardless of your weight. Most people, however, are a combination of all three, with a tendency to be more like one or two of them.
Some people have a naturally high metabolic thermostat -they tend to burn more calories than average even when they’re asleep. Other individuals need fewer calories for the same physical activity. These metabolic differences alone, however, aren’t great enough to account for weights that exceed the healthy ranges in weight tables.
Gender and Weight
Why does it seem men can eat more of everything than women without gaining weight? One explanation is that men have more muscle and less fat than women.
Muscle uses more energy than fat. Because men have more muscle, they burn between 10 and 20 percent more calories than women during rest.