We’re All Likely to Get Fat

So you’ve kept a fairly trim physique into middle age. Don’t get smug. A new study suggests that you too may develop a paunch or worse in coming years.

Since 1948, researchers have been studying heart health and related factors in a large group of people—and their descendants—living in Framingham, Mass. The current study analyzed 3 decades of data that had been collected on some 4,000 men and women beginning in 1971. When the study began, all participants had been between the ages of 30 and 60.

Researchers computed body-mass index (BMI)—essentially how slim or heavy an individual was—for each person, as surveyed every 4 years. In the Oct. 4 Annals of Internal Medicine, Ramachandran S. Vasan and his colleagues with the Framingham Heart Study offer up some disturbing data.

Between 17 and 34 percent of the women, depending on their age, and about half of the men were already overweight when the study commenced. Over the next 30 years, most of the other participants gained considerable heft, as well. By the end, more than 75 percent of women and 90 percent of men were at least overweight. Roughly half were heavy enough to qualify as obese.

For perspective, a 5-foot, 2-inch woman would have to weigh at least 136 pounds to qualify as overweight, and a 5-foot, 10-inch man would have to top the scales at a minimum of 174 pounds. These two people would be classified as obese if she weighed at least 164 pounds and he weighed 209 pounds or more. Those are the figures that put both members of this couple at a BMI of 30. You can find your BMI, according to your height and weight, at http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.htm.

Study participants who were in their early 30s or 40s when the research began faced the greatest risk of gaining weight: 90 percent of them ended up at least overweight.

The rates of being overweight and obese among people in this study are higher than those reported in earlier research, Vasan notes. However, he’s not surprised. “Previous studies have been cross-sectional,” he says, “which means they took a snapshot of the community at one point in time to tell us what proportion of people was overweight or obese.” Here, the researchers summed the data from a host of snapshots to uncover the probability that a participant might eventually become at least overweight.

The really troubling finding, this cardiologist says, is that “if you reach middle age and have a normal BMI, you still don’t escape the possibility that you may become overweight or obese.”

The study was not designed to probe what factors most contributed to chronic weight gain—such as overeating or exercising too little. “That’s a very important question for future research,” Vasan says.

As it is, the health implications of the new findings are enormous, he notes, because hosts of studies have shown that being overweight increases an individual’s risk not only of heart disease, but also of diabetes, cancer, stroke, osteoarthritis, gallbladder disease, and breathing problems such as asthma and sleep apnea.

Data on one federal Web site offer clues to why middle age and elderly people may be putting on extra pounds. It shows the inflationary creep in food portions over the past 2 decades. For instance, 3-inch bagels have given way to 6-inch ones typically containing 350 calories each. Fast-food cheeseburgers used to provide 333 calories each, but a typical offering today has 590 calories. And a plate of spaghetti and meatballs at most restaurants now delivers more than twice the 500 calories typical of portions served in the mid-1980s.

This portion distortion is insidious: Every extra 10 calories consumed per day—and not burned up in exercise or work—will add another pound of flesh or fat by the end of a year (see Dietary Inflation).

Over the past decade, people have been dining out with increasing frequency (see Home Cooking on the Wane). Last year, U.S. restaurants served up more than 70 billion meals and snacks. With people eating out more than ever, the supersizing of restaurant-meal portions risks contributing substantially to the supersizing of our waistlines—and our health risks.

Janet Raloff

Janet Raloff is the editor of Science News for Students, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer.

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