Diabetes.
It happens that many people say it's diabetes, where the digestive system lacks something! I'm so sorry this answer is terrible!
It provides exercise to the body keeping it fit and calm. Hope this helps.
They both mean two completely different things. They are useful for doctors to tell when determining when someone may be obese or underweight. Both of these weight problems can lead to much more severe and fatal illnesses such as anorexia nervosa, bulimia nervosa, diabetes, heart disease, etc.
Obesity for over weight
anorexia for being under weight
