Which of the following is NOT a method to assess body composition?

Body mass index (BMI) is not a direct method used to assess body composition because it is a calculation based solely on a person's weight and height. BMI provides a general indication of whether an individual falls into underweight, normal weight, overweight, or obese categories but does not differentiate between muscle mass, fat mass, or other components of body composition.

In contrast, the other methods mentioned—DEXA, skinfold thickness, and bioelectrical impedance—are more accurate in assessing body composition directly. DEXA (Dual-Energy X-ray Absorptiometry) provides detailed information about bone density, fat mass, and lean body mass. Skinfold thickness measurements estimate body fat by measuring the thickness of skinfolds at various body sites. Bioelectrical impedance analysis (BIA) estimates body composition by measuring the resistance of body tissues to electrical currents, allowing for the differentiation between fat mass and lean body mass. Each of these methods offers a more nuanced view of body composition than BMI alone.