Why We're Fat
Gender and age matter more than you may realize
Isn't it just like a man? Although his 56-year-old wife, Maureen, had been counting calories since her teens, Tom Javaux ate what he wanted and remained trim well into middle age. When the 62-year-old retired bricklayer finally developed a paunch and went on the same diet as his wife, he dropped more weight and lost it faster than she did--50 pounds to her 35.
Another injustice between the sexes? You bet. The latest obesity research shows that men and women differ in almost every respect when it comes to weight over the course of a lifetime: when they gain it, where they gain it, and at what rate. In women, sex hormones wreak havoc on the ability to control appetite, energy expenditure, and fat storage. In men, it is the slowing down of physical activity that tends to add pounds. But overweight men, because of where they carry their weight, can be at higher risk than women for heart disease and other serious health problems.
Despite the differences, the body shapes of both sexes share one alarming similarity: Both men and women are getting fat in epidemic proportions. Well over half of all American adults--about 63 percent of men and 55 percent of women age 25 and older--are overweight. Last week, in a special issue devoted entirely to obesity, the Journal of the American Medical Association reported new statistics that are nothing short of astonishing for a nation seemingly so obsessed with health and fitness: The rate of obesity--18 percent--has soared from 12 percent just seven years ago, making the United States now secure in its position as the fattest nation in the developed world.
"This rate is shocking," says Jeffrey Koplan, director of the Centers for Disease Control and Prevention, "and it means that we have a huge public-health problem." Indeed, depending on weight and age, obesity significantly increases the risk of high blood pressure and high cholesterol, diabetes, and gallbladder disease.
Obesity is determined by a measure called the body mass index, or BMI, which tallies weight adjusted for height. A BMI of 18 to 24.9 is considered normal, 25 to 29.9 is overweight, and 30 or higher is obese. A woman 5 feet, 5 inches tall who weighs 162 pounds is considered overweight; if she weighs 186 pounds she is obese. A 5-foot, 10-inch man who weighs 188 pounds is overweight; if he weighs 216 pounds he is obese. Both the overweight man and the overweight woman have BMIs of 27; the obese pair have BMIs of 31.
The prevalence of obesity may be troubling, but it shouldn't be all that surprising. As a species, humans have evolved with instincts to seek and store fat. Easy fat storage is crucial for survival in times of famine, yet for decades Americans have been seated at a veritable feast. Says Tom Wadden, director of the Weight and Eating Disorders Program at the University of Pennsylvania, "Now it has become a maladaptive trait because we are living in times when we have a surplus of food." As a result, he says, "we are all getting obese."
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