There are two basic mechanism groups defining the weight of a person: one, that adjusts calorie input based on the weight and one that adjusts output based on w

There are two basic mechanism groups defining the weight of a person: one, that adjusts calorie input based on the weight and one that adjusts output based on weight. Some of these mechanisms are physiological (stress eating), some physical (it is harder to walk for a overweight person). System dynamics basically tells us being over-, or underweight comes from these mechanims being unbalanced. For some reason the automated adjustments do not kick in on time and at sufficient volume.