Final answer:
The concept in question, known as the set-point, is a weight that the body naturally maintains through compensatory mechanisms. BMI is a tool used to standardize the notion of ideal body weight relative to height but has its limitations.
Step-by-step explanation:
The specific body weight maintained automatically by most adults over long periods of time without significant fluctuations is referred to as the set-point. This set-point theory suggests that each person has a genetically predetermined weight that the body attempts to maintain, which can resist changes due to compensatory adjustments in energy intake and expenditure. It's akin to a form of homeostasis for body weight.
The concept of an ideal Body Weight is complex and influenced by factors including sex, muscle mass, bone density, age, and height. It's further shaped by cultural perspectives and societal standards of beauty. To medically standardize this notion, the body mass index (BMI) is often used, correlating weight in relation to height with health risks.