A few weeks ago, I was eating in a restaurant in West Virginia
(the second fattest state in the country), staring blankly at a television and thinking, I really should join a gym; this sitting-on-my-butt-all-day-occupation is showing. Suddenly the newscaster said, "Before you start that next diet, you won't want to miss this one! A new study suggests that those few extra pounds may actually help you live longer." To say there was a collective sigh of relief in the restaurant-in the entire country-would be an understatement. I found myself surrounded by strangers gaping at each other as if the newscaster had just announced the end of a military occupation: Did you hear that? We're free! They joked about ordering more pie, and I half expected everyone to start toasting one another with French fries.
The headlines read like a dream: "Gov't Overstated Danger of Obesity," "Fat May Be Good." Two New York Times columnists said that the fight against obesity had "lost the scientific high ground." They taunted "people who work out, eat responsibly," those "salad-munching health nuts" who, they gloated, would die young because, according to a Centers for Disease Control and Prevention study, "overweight people actually live longer than normal-weight people."
But wait: Only a month earlier, the Washington Post had reported a high-profile University of Illinois study showing that skyrocketing obesity rates are shortening life spans "[more] than the impact of car accidents, homicides and suicides combined." And major news outlets said studies revealed that "obesity triples the risk of dementia" and causes breathing problems. So what's the deal?
The deal is that the media didn't push to analyze the CDC report-they just jumped on good headlines. The study is titled "Excess Deaths Associated with Underweight, Overweight, and Obesity." How anyone could read that and reduce it to "Studies Show: Being Fat Is Not So Bad" is beyond me. These results corroborated an overwhelming body of research: Obesity is linked to deadly
diseases. The CDC did find that fewer people died in 2000 from obesity-related causes (111,909) than had been previously estimated (365,000). But estimating obesity deaths, as the study points out, "raises complex methodologic issues," and its own methodology "has important limitations."
One of these is controlling for underlying disease. "Many diseases and medications cause people to gain or lose weight," notes Tobias Kurth, a Harvard University obesity researcher. "If you don't control for these and just look at who's dying and how big they are, you can get a skewed view of the world. Using this study to say being overweight is protective is simply overstating the scientific data." There's also the well-known "obesity paradox," that being slightly overweight can offer protection for the elderly, though the truly obese are less likely to grow old enough to see any such benefit.
The study's most obvious limitation is its use of the unreliable "body mass index" (BMI)-a number determined by a person's height and weight-to define "normal" and "overweight." A BMI of between 18.5 and 24.9 is "normal," between 25 and 29.9 "overweight," and 30 or more "obese." But BMI doesn't take into account many important factors: physical activity, fat versus muscle, gender, diet. This means George W. Bush-a nearly-six-foot-tall 200-pound guy who eats well and works out regularly-has the same BMI as a six-foot-tall 200-pound guy who sits on the couch all day eating junk. With a BMI of 27.1, they're both "overweight." But President Bush has precisely the right amount of body fat for his age, and he's in great cardiovascular health. I'd like to see the same study use some kind of body fat index. Bush's percentage of body fat is 18.3, which is considered excellent for his age. Not the case for that out-of-shape guy on the couch.
Major-media coverage didn't raise these questions. Instead it tended to compound the problem with fuzzy math, often reporting that 25,814 Americans died from obesity, though the
actual number was 111,909. Because the CDC study documented fewer deaths in the "overweight" category than in the "normal" category, the media subtracted the number of overweight people who didn't die from the number of obese people who did-as if deaths that don't happen somehow cancel out deaths that do.
A companion study did find that overweight and obese people have lower cholesterol levels and blood pressure than they did in the past. This doesn't show that obesity is inherently less dangerous; it shows that medicine has gotten better at treating some of its effects. Obese people may be living longer, but those extra years are full of heavy medication, diabetes, sleep apnea, stroke, asthma, blood clots, heart disease and cancer. And obesity is still one of the top causes of preventable death, which is why the CDC cautioned that people shouldn't use this study as an excuse to be overweight.
It's good news that people can live longer with obesity, but that's no excuse to blow off exercise and order more pie-precisely what the coverage has encouraged. And don't get me started on those huge fast-food-industry-funded ads declaring that obesity is officially "hype." They make me want to scream. There is no science saying that obesity is OK. That's not hype. It's scientific fact.
2 OTHER RECENT HEADLINES THAT MAY HAVE MISLED YOU
"antioxidants a key to long life" Well, maybe. This study wasn't about antioxidants you buy at a store. It looked at mice that were genetically engineered to produce antioxidants. Interesting, sure, but don't gorge on supplements-they're toxic at high doses.
"whiskey helps fight cancer" We wish. The truth: Whiskey contains ellagic acid, a plant-based antioxidant that's been found to help decrease cancer risk. (It's also in red wine.) But it's present in much higher quantities in soft fruits. Meanwhile, there's plenty of research connecting booze to various kinds of cancer.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.