The Problem with BMI and the Number You Should Watch

Body Mass Index (BMI) had been one of the main criteria used to determine whether a person is overweight or obese. It was developed as a relatively easy screening tool, but it’s far from a perfect measurement. Recently, BMI has drawn criticism as to whether it’s an accurate assessment of health. For example, a high BMI does not take into account muscle mass and other critical factors that may impact health.

“BMI is an indirect measure of body composition meaning that it does not actually measure fat but calculates it based on height and weight,” says sports dietitian Marie Spano, RD, a certified strength and conditioning specialist, adding, “a person with high muscle mass can be categorized as obese or a person with high body fat and a low body weight may have a normal BMI yet an unhealthy amount of fat.”

Recently, many health practitioners are turning to waist-circumference measurements to help predict future disease risk. Waist circumference has been shown to be more reflective of visceral (deep) fat levels and future health risks such as the development of Type 2 diabetes, cardiovascular disease and certain cancers.


Manuel Villacorta, RD, author of the upcoming book “Flat Belly 365” has had personal experience with BMI being inaccurate: “As a short, muscular man, I was once told I was overweight by a nurse based on my BMI.” For himself and his clients, he prefers to use waist circumference to monitor health.


As we learn more about the dangerous role excess levels of visceral fat play in the body, tracking and monitoring changes in waist circumference is becoming more critical to disease prevention. The increased visceral fat coats internal organs like a blanket. Although this fat provides stored energy, it can also secrete inflammatory chemicals called cytokines, which can trigger bodywide inflammation, increasing disease risk.

Although everyone should be aware of their own waist circumference measurement, individuals who have a BMI within the normal range may stand to benefit from tracking this measurement the most. “People who have a normal BMI may carry a good amount of their weight in their stomach which increases their risk for chronic diseases,” says Spano. For men, waist-circumference levels should be below 40 inches, and for women it should be below 35 inches. Even if your waist is within the normal range, you should monitor it for changes over time. A widening waistline may highlight an increased risk for disease.


If you need to reduce your waist circumference, dietary changes are in order: Fill up on produce, whole grains and healthy plant-based fats to help shed visceral fat. “It does not matter how much you exercise, nutrition is 80% of the battle,” explains Villacorta, adding that, “focusing on nutrients and antioxidants that can fight inflammation caused by excess visceral fat and making sure you are eating to promote a healthy gut microbiome may help.”

To eat your way to a slimmer waistline, balance your meals by filling half of your plate with vegetables and fruit. Aim to eat a diet rich in fermented foods such as yogurt, sauerkraut and tempeh to improve gut health and limit eating large amounts of inflammatory foods such as those rich in added sugars.

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(via MyFitnessPal Blog)

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