If you’re overweight but keep yourself in shape by running half marathons or doing hill drills on your bike each day, you might think such a high level of physical activity counterbalances the extra pounds — but recent research suggests otherwise.
A new study challenges the concept of “healthy obesity.” Published in the August 2017 issue of the European Heart Journal, researchers tested the hypothesis that individuals without any metabolism dysfunctions, who still carry excess weight, have no greater cardiovascular risk than their leaner counterparts. The researchers defined “obesity” and “overweight” using body mass index (BMI), and “unhealthy” using indicators like elevated blood pressure, hyperglycemia, high waist circumference, hypertriglyceridemia (a condition of high blood levels of fatty molecules) and low HDL-cholesterol.
Using an analysis of 520,000 people from the European Prospective Investigation into Cancer and Nutrition study, researchers compared the following two measurements between overweight/obese people and metabolically healthy normal weight people:
- Hazard ratios: How often an event happens in one group versus how often it happens in another group over a period of time. In this case, the study looked at incidents of coronary heart disease over 12.2 years.
- Confidence intervals: The probability a population parameter falling between two particular values. In this case, researchers accounted for gender, age, education, smoking, diet and exercise at 95% confidence intervals, meaning, they expect 95% of the intervals will include the parameter.
CAN WEIGHT BE SECONDARY TO FITNESS?
Results showed that regardless of metabolic health, overweight and obese people had higher cardiovascular health risk than lean people. The study also found that weight increases your risk of heart disease by 25%, even when everything else falls in the normal range. In short, any amount of extra weight can be bad for your health. These findings are contrary to the belief that as long as you’re fit, weight is secondary.
LaFarra Young, MD, general adult and pediatric pathologist in Brookhaven, Mississippi, affirms the study’s results, “Overweight and obese individuals with healthy metabolic function continue to have a slightly higher risk of coronary heart disease than lean individuals.” She recommends these individuals pay close attention to metabolic health factors when determining risk factors for various diseases and complete mandatory follow-up with a health care provider when determining the status of their metabolic health through the parameters discussed in the study. In addition, “Individuals with a high BMI, but not quite overweight, considered normal weight, should definitely get regular checkups to ensure their metabolic health is intact.”
A CAVEAT ON BMI
“The BMI is used to help determine an individual’s level of fitness and, by extension, their risk of chronic diseases. Healthy [BMIs] fall between the 18.5–24.9 range, with any score over 30 considered obese,” says Faisal Tawwab, MD, of Multicare Physicians DPC in Lake Mary, Florida. However, Tawwab notes, “measuring BMI is not a perfect science, especially when taking different body types into consideration. However, it does serve as a good indicator of whether or not lifestyle changes need to occur.”
READ MORE > EVEN ENDURANCE ATHLETES ARE AT RISK FOR THIS
BMI should not be a sole determinant of an individual’s risk of specific health outcomes. “An individual’s genetic makeup and metabolic health determines the effect of a larger BMI on their risk for coronary heart disease,” says Young. Often athletes with high muscle mass may have a high BMI (up to 25), even though they’re actually not considered overweight. “Various factors determine the cause of this scenario, such as high muscle content. In cases where people are concerned about future health complications, a determination of body fat as well as lifestyle may be very informative,” she says.
