Your BMI doesn’t tell the whole story. Nutrition Diva has other tools to evaluate your health and disease risks.
There’s been a lot of buzz lately over a new study which seems to suggest that people who are overweight (but not obese) may actually have a higher life expectancy than those who are considered normal or healthy weight. In this analysis, researchers categorized people as normal weight, overweight, or obese using Body Mass Index (BMI), a number that takes into consideration your weight and your height. Many people chalked these surprising results up to the limitations of the BMI as an indicator.>
The BMI doesn’t account for body composition; that is, the relative proportion of fat and muscle tissue. People often point out that a bodybuilder with lots of muscle and very little fat could easily have a BMI in the “obese” category. But let’s be honest, bodybuilders account for an extremely small fraction of the general population. As a simple tool for assessing the general population, the BMI is actually fairly reliable.
Others took these new results to mean that being overweight simply isn’t as dangerous to your health as everyone claims. I even saw bloggers suggesting that the obesity epidemic is simply a hoax dreamed up by the dieting industry to sell books and weight loss drugs. I think that’s a rather silly, not to mention dangerous, position.
Do Overweight People Live Longer?
In this latest analysis, people who were obese had the highest risk of death. But people who were in the overweight category actually had a lower risk of death than those who fell into the normal BMI category. That may seem surprising, until you consider the fact that the study lumped together people of all ages and in all states of health.
In a general population like this one, many people will end up dying of cancer, which is the second leading cause of death in most Western countries. Although obesity can increase your risk of getting cancer, people who are sick with cancer almost always lose a great deal of their body mass. People who die of old age also typically experience a loss of body mass in the last years of life. In other words, what this study really shows is that people who are very sick or very close to the end of their lives are likely to have a lower BMI. But that doesn’t mean that being heavy is a way to extend your lifespan.
In fact, when you filter out people who are underweight due to advanced age or serious illness, it’s pretty clear that being overweight increases your risk of many diseases and ultimately reduces life expectancy. The more overweight you are, the shorter your life expectancy. Statistically speaking, your long-term risks are lowest if your BMI is between 18.5 and 25. (Click here to calculate your BMI.)
Weight is Not the Only Measure of Health
Of course, statistics are most meaningful when you’re trying to predict outcomes in a large group of people. When it comes down to assessing the health of an individual (such as you), body weight (or BMI) is clearly not the end of the story. In addition to hopping on the scale, I suggest that you consider the following indicators, as well:
Waist circumference. Measuring your waist is an easy way to assess visceral adiposity, which is a fancy way of saying belly fat. Ten pounds of extra weight is much more dangerous to your health if it’s all sitting right around your middle, as opposed to distributed more evenly around your body. If you’re a woman, your waist measurement should be at least 15% smaller than your hips. Guys, your waist should be at least 5% smaller than your hips.
Fasting Blood Sugar. Although being overweight is definitely a risk factor for developing Type 2 diabetes, it’s not a perfect predictor. Some normal weight people develop Type 2 diabetes and some obese people do not. Regardless of your weight, a
high fasting blood sugar suggests that you may be in danger of developing Type 2 diabetes.
See also: Reversing Diabetes with Diet
Blood Pressure. High blood pressure raises your risk of a stroke, of course. But even in the absence of a stroke, high blood pressure can cause serious damage to your heart, blood vessels, kidneys and brain. Although body weight and blood pressure often go up together, you can have high blood pressure even if your weight is normal. You can also have normal blood pressure even if you’re overweight.
Fitness. Your general fitness level is also an important indicator of your health and disease risks. You don’t have to be an elite athlete. You don’t even have to be thin. But you should be able to walk a mile in 15 minutes, walk up 2 flights of stairs without huffing and puffing, and be able to do 5-10 pushups. (If not, you should be working toward those goals, regardless of your weight.)
Can You Be Overweight and Healthy?
So, here’s an offer for those of you who reject the notion that body weight is a valid indicator of health risks. If you are moderately overweight (with BMI not more than 29), but your waist is smaller than your hips, your blood sugar and blood pressure are normal, and you are reasonably fit, it might suggest that the extra pounds you’re carrying are not drastically impacting your health risks. And by the same token, if your weight is in the normal range but any of these other indicators aren’t, it suggests that you have some additional work to do.
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