How Much Does Weight Matter?

Based on the information in mainstream magazines, news reports, and even some doctor’s offices, many Americans believe health is a numbers game — calories, pounds, and body mass index (BMI) are composed of digits that supposedly paint a complete picture of a person’s well-being.

But new evidence suggests that a “healthy” number on the scale isn’t necessarily indicative of a healthy body. Some experts now argue that wholesome habits and lifestyle choices count more than many measures traditionally used to size up overall wellness — like a low weight, thin frame, and fit appearance. In fact, they argue, bad habits and poor health can be masquerading in the form of “skinny fat.”

The oxymoronic phenomenon is also known by various acronyms, including MONW (metabolically obese normal weight) and TOFI (thin outside, fat inside). People who fall into this category may look thin, weigh a “normal” amount, and maintain a “healthy” BMI, but their appearance conceals chronically unhealthy behaviors leading to consequences typically associated with overweight or obese individuals.

So how can a person simultaneously be labeled skinny and fat? By keeping the fat concealed. Using MRI scans to examine the amount of “internal fat” people have, Professor Jimmy Bell, featured in the documentary “Fed Up,” has demonstrated that outwardly thin people can conceal large quantities of fat within their bodies.

Where you store fat matters. Consider thin junk-food addicts, who seem to have the ability to eat whatever they want, skip the gym, and still fit into their skinny jeans – think they’re just lucky? Think again: These folks could face more healthy consequences for their junk food habit than their fit but overweight counterparts.

The science is clear that thinness is not a guaranteed ticket to good health or even a long life. Despite the ever-present warnings about the health implications of an expanding waistline, a report from the Centers for Disease Control (CDC) and the National Cancer Institute found that overweight people appear to have longer life expectancies than normal-weight adults. And a 12-year study in the Journal of the American Medical Association found that adults over 60 with a BMI of 25 to 30 had slightly lower death rates than normal weight subjects.

One of the main issues with the skinny-fat phenomenon is that a thin appearance can obscure the amount of dangerous visceral or “deep” fat that wraps around inner organs, increasing the risk for diabetes, heart disease, and stroke. A study in the Journal of the American College of Cardiology found that this kind of fat, which is not always visible outside the body, may be significantly more dangerous than other types of more superficial fat located directly under the skin, also known as subcutaneous fat. Of more than 3,000 people followed over five years, those with higher amounts of visceral fat were more likely to develop heart disease and cancer. The amount of subcutaneous fat—the type we typically write off as “unhealthy”—was unrelated to the risks.

A report in the Archives of Internal Medicine comparing weight and cardiovascular risk factors in 5,400 adults found that half of overweight and one-third of obese subjects were found to be “metabolically healthy,” despite the fact that many health professionals would advise them to shed a few pounds. And although the majority of participants within the healthy weight range were also metabolically fit, a quarter of them showed at least two cardiovascular risk factors associated with diabetes, which is commonly linked with excess weight.

And it’s not just adults who are affected. A study published online in Pediatrics last year found that from 2000 to 2008, the number of teens aged 12 to 19 with pre-diabetes increased from 9 percent to 23 percent. Of the normal-weight kids, 13 percent were either pre-diabetic or diabetic, and 37 percent had one or more cardiovascular risk factors including elevated blood pressure and cholesterol.

Rather than scrutinizing the numbers on the scale or BMI chart, examine your patterns around food and exercise. Despite the fact that many medical professionals still use BMI to assess relative size, the formula may not really be an accurate measurement of overall health. For example, anyone with heavy bones or a large amount of muscle can fall into a higher BMI category even while maintaining a low body fat percentage.

A better way to assess whether the risks associated with being skinny fat apply to you is to pay attention to your lifestyle habits and to work with a provider to get the appropriate tests. Blood sugar, triglyceride, cholesterol, and blood pressure levels can indicate much more about overall health than weight.

It’s not that weight doesn’t matter at all—it’s just part of the picture. Ditch the diet mentality and consider food and exercise as tools to improve your overall health, independent of your size. Even if you’re not trying to drop pounds, cut out processed foods and focus on filling your plate with whole foods including vegetables, grains, and protein. Find physical activities you enjoy doing—even if you’re thin. Finally, aim for a combination of cardio and strength training to build muscle, work your heart, and stay in top shape.