We know that carrying some extra weight can increase the risks of conditions like heart disease, high cholesterol, elevated blood pressure, diabetes, stroke, and even death. But is being slightly overweight really so unhealthy? The answer might surprise you.
Excess weight and a laundry list of healthy concerns are not always synonymous. But, don’t be so quick to ward off a healthy diet and exercise — this subgroup of overweight people, dubbed the metabolically healthy obese, fit some very specific criteria.
Defining the risks
Body mass index: An individual’s risks for these conditions don’t depend solely on the numbers that appear on the scale, nor on any other single measure, like body mass index.
Body mass index (BMI) is a measure used to determine body fat based on a person’s height and weight, and is typically used to assess the risks your weight has on your health, but even that is an imperfect measure.
“I use risk to define everything,” Neil McDevitt, MD, a bariatric surgeon with Summerville Medical Center says. “There's a lot of social issues that go into what people feel comfortable with, so we use a BMI chart to give us an overall gestalt of what your general risk is, based on your weight,” he adds.
By definition, overweight and obese people have a BMI greater than 25 or 30, respectively, but, “there's a weakness inherent in BMI charts,” McDevitt says. “It doesn't take into consideration muscle mass.”
That’s not all. The healthiest BMI for longevity might not fall within the normal range (18.5 to 25), although the jury is still out on the optimal BMI for lowest mortality. In fact, one study suggests the “sweet spot” for longevity is a BMI of 27, which you’ll find right in the middle of the overweight range. Other studies, still, suggest the lowest rates of mortality are among those with a BMI between 20 and 24.
Hip-to-waist ratio: Concerns over weight may not be directly related to how much fat a person is carrying, but where on the body they’re carrying it. One major risk factor of metabolic syndrome is a large midsection, often described as an “apple-shaped” figure.
“We look at something called the hip-to-waist ratio,” McDevitt says. “The World Health Organization says that abdominal obesity is significantly more of a risk factor than obesity of the periphery of the body.”
The measure used to determine fat distribution is known as hip-to-waist ratio — a comparison between the smallest part of the waist and largest part of the hip. A ratio of one or greater for men and .8 or greater for women, is considered an apple shape, and thus carries a greater potential for obesity-related health risks and death.
In combination with BMI, waist circumference gives a good picture a person’s risk of obesity-related mortality — even if you fall within a healthy BMI range.