Answer:
Body type
Step-by-step explanation:
Not an expert on this topic, but this is because everyone's body is different, so that affects what the healthy outcome is. For example, if someone has a body type that is slightly overweight or underweight from birth (from genes and such) they can't help having a different body. So what that means is that their healthy weight might be considered overweight/underweight compared to more "normal" body types.