Final answer:
Body weight minus non-essential fat equals lean body mass, which is a true statement. Lean body mass is crucial for a better assessment of health because it represents the fat-free content of the body, unlike BMI, which can't distinguish between muscle and fat weight.
Step-by-step explanation:
The statement body weight minus non-essential fat equals lean body mass is true. Lean body mass includes weight from muscles, bones, organs, and other tissues, excluding all types of fat. The non-essential fat is the fat that our body does not require for physiological functions.
Lean body mass is an important measure because it helps differentiate between weight that comes from fat and weight that comes from muscle, bone, and organ tissue. This is important since different tissue types have different implications for health. A person's lean body mass is a better indicator of fitness than their total body weight because it takes into account muscle content rather than fat content.
The body mass index (BMI) is another tool commonly used to estimate a healthy body weight based on a person's height and weight. However, BMI can be misleading because, by design, it does not distinguish between muscle and fat weight. Therefore, someone with a high muscle mass might be classified as overweight or obese when they are actually in very good health.