Different Sexes, Different Bodies

While the fundamental principles of weight loss are the same for both genders—expending more calories than are taken in—the elements that lead to the creation of the caloric deficit that invokes weight loss are not. Indeed, men and women are different; they are biologically different and emotionally different. Because both biology and psychology are integral to successful weight loss, these differences are extremely important.

The physical variations between the genders require little explanation. The body composition—that is, the proportions of muscle, bone, and fat that make up the male and female bodies—of men and women are quite different. A typical man who weighs 154 pounds has 69 pounds of muscle, 23 pounds of bone, and 23 pounds of fat (the rest is organs, body fluids, and the like). A typical woman who weighs 125 pounds has 45 pounds of muscle, 15 pounds of
bone, and 34 pounds of fat. In summary, men are genetically programmed to have more lean muscle mass and heavier bones than women. Conversely, women’s bodies are designed to have a higher fat content.

Technically, the definitions of overweight and obesity are based on the presence of excess body fat (though Body Mass Index or BMI is used to categorize people’s weight status—more on this in the next chapter).
Here, too, the genders differ. Overweight in men is defined as between 21 and 25 percent body fat and obesity is defined as greater than 25 percent. Overweight in women is defined as between 31 and 33 percent body fat and obesity is defined as greater than 33 percent.

Because biologically men are supposed to have less fat and women more fat, even men and women of the same height and weight should have very different body compositions.
Given the physical differences between the genders when it comes to body composition, it’s not surprising that body fat recommendations for men and women are different as well. The recommendation for men ranges from 12 to 20 percent and that for women ranges from 20
to 30 percent.

Given their different body compositions, men have a biological advantage over women when it comes to losing weight.