The Skinny on Weight
Calvin Trillin has attributed an astute observation to his father, who said something like, "You can't gain more weight than that of the food...
Calvin Trillin has attributed an astute observation to his father, who said something like, "You can't gain more weight than that of the food you eat." That makes perfect sense to me, but some people feel that there's something very mysterious about body weight--that it's somehow magical or fated. Like weather forecasting, weight is both a conundrum and a national obsession. A recent survey of 107,804 adults conducted by the Centers for Disease Control (CDC) in Atlanta indicates that more than two-thirds of adult Americans are trying to lose weight. All of survey of 107,804 adults conducted by the Centers for Disease Control (CDC) in Atlanta indicates that more than two-thirds of adult Americans are trying to lose weight. All of them would probably like to know why they weigh more than they want to--how much of it is related to differences in appetite, caloric consumption, exercise level, the type of foods they eat, their genetic profile, or other factors. Specialists in diet, metabolism, and nutrition would like to know, too, and would be just as likely to disagree about the details.
As difficult as it is to determine why people gain weight, there are at least two variables whose effect is dependable: calorie consumption and exercise. Weight-loss guidelines developed by the National Heart, Lung, and Blood Institute more or less acknowledge this. Released in 1998, the NHLBI weight-loss prescription recommends that--depending on the severity of the individual case and the speed of weight loss desired--obese people cut from 500 to 1,000 calories out of their daily diet: for example, an eight-ounce hamburger (roughly 600 calories) on a bun (about 75), with a small order of fries (about 200) and a small nondiet soda (about 150). At the same time, they should begin a regimen of physical activity, starting with at least three weekly, 30-minute sessions of walking at any speed, progressing to 45 minutes of more vigorous exercise (such as rapid walking) at least five days a week. That's a simple formula and, according to the NHLBI, people who follow it should lose roughly 10 percent of their body weight in six months, and keep it off.
The problem is that so few people seem to be listening. Obesity, as a recent theme issue of the Journal of the American Medical Association (JAMA) shows, has become a national epidemic, with rates rising from 12 percent in 1991 to almost 18 percent in 1998. More than half of all adults in this country are considered to be overweight or, worse, obese. Another CDC survey points out that although we spend about $33 billion a year on weight control, only one out of five slimming Americans follows the NHLBI's recommended combination of diet and exercise. Many people reported reducing their calorie intake and/or increasing their physical activity, but not at the NHLBI levels. In fact, more than half of all Americans engage in little or only irregular exercise.
Is this important? Excess weight clearly poses a major health risk. Once considered a risk factor for heart disease only in combination with other conditions, like smoking or high cholesterol, obesity was recently elevated to the level of an independent risk factor; in other words, whatever your other health habits are, simply being obese raises your risk of heart attack. Excess weight has also been implicated in the development of hypertension, stroke, gallbladder disease, sleep apnea, arthritis, high cholesterol, and endometrial, breast, prostate, and colon cancers.
According to a study by professor of medicine Graham Colditz, D.P.H. '86, and colleagues, obesity accounts for almost $100 billion in annual national outlay reflecting everything from healthcare costs to lost wages to reduced productivity. But there are many more effects that can't be easily counted. This article, for example, can't even begin to examine the effects of discrimination against heavy people, but there's no doubt that the impact on both their physical and their mental health is significant. (The NHLBI, incidentally, refers to obesity as a "disease," a designation that has been vigorously fought by some advocates for overweight people.)
Throughout the years, people wanting to keep a healthy-looking shape have been offered many prescriptions. The late, great Harvard and Massachusetts General Hospital cardiologist Paul Dudley White said, "The only way for a rich man to be healthy is--by exercise and abstinence--to live as if he were poor." Today, White's health message would be difficult to interpret. Obesity is as rampant among low-income Americans as it is among those better-off. The paunchy patrician and well-fed society matron are images of the past. The well-heeled of our times wear cross-trainers and hire a personal coach whose job is to make sure the calories from last night's tiramisu are torched from existence.
But as Steven L. Gortmaker, senior lecturer on sociology in the Faculty of Public Health, observes, people both rich and poor watch television, and the mere absence of activity such "activity" creates can lead to critical weight gain. "Long-term studies show that TV watching in children is predictive of weight gain," Gortmaker says. "We think that takes place for two reasons. First, it's an average of two hours per day of inactive time when you're just sitting in a chair. Second, there's constant reinforcement to consume high-caloric density, nutritionally vacuous foods. We think that combination of inactivity and advertising easily leads to another 100 calories a day, and that's all you need to become obese over time."
"I think that all most adults need to do to address obesity is reduce TV time and, instead, do something they like," Gortmaker continues. "Kids, too, should not think that they have to replace TV time with running; replacing it with anything they like is fine."
In other words, people don't need to become marathon runners overnight to avoid obesity and its health risks. Assistant professor of medicine and of epidemiology I-Min Lee, M.P.H. '87, S.D. '91, who has investigated the problem extensively, says that studies have not been totally consistent, but it's generally believed that even low levels of exercise will confer some benefit. Almost any level of activity--walking, biking, climbing stairs at home or work--will conduce to reduced weight and better health. "I think it's a continuous spectrum," Lee says. "If you do a little bit, you should expect some limited benefit. If a real couch potato gets off the couch and starts walking, that's got to do some good. But we have to try to keep people moving up and doing more exercise. Once you reach the level of doing moderate exercise, you should still be encouraged to do more."
Unfortunately, although studies show that physician attitudes make a huge difference in the likelihood that a patient will start exercising, fewer than half of all patients ever get that exhortation from their doctors, according to a report in the recent JAMA issue on obesity. In addition, doctors were more likely to recommend exercise to people who were already trying to lose weight; those who were making no attempt to lose weight received the least encouragement to do so.
Weight may always be a confusing concept, and overweight people will no doubt continue searching for hassle-free ways of losing it. But physicians can take a lot of the guesswork out of the situation by recommending exercise to their patients, even to those who only hover on the brink of obesity. Perhaps physicians should start issuing a standard prescription: "Turn off the TV, take a walk, and climb some stairs every day." That's an unambiguous message that could probably save thousands of lives, and make them fuller and more rewarding, too.
Contributing editor John F. Lauerman writes from Brookline, Massachusetts.
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