A class I fat is moderately obese: clothes now contain an X somewhere in the size, and ambulation is reduced. A class II fat is full-on obese: All pretense of moderation is abandonded. Meals become the focus of all activity, still considered mobile for flat or gentle downhill slopes. A class III fat is morbidly obese: The gut becomes so large that the arms cannot hang normally at their sides. If you look closely at a class III morbid waddle, you'll notice the palms of their hands face entirely backwards during it's gait (a normal human gait has palms facing inward towards the waist). A class IV death fat: mobility is only for seconds at a time, otherwise assistance of some form must be used such as a scooter or tractor trailer. Health is rapidly deteriorating and the food addiction has compleltely taken over all aspects of the eatbeast's life. See My 600 lbs Life for examples. A class V super whale: Usually pictured on tabloids with the phrase "<insert country here>'s fattest <gender> cut out of house for emergency decouching" with pictures of the amorphous blog being craned to the nearest hospital. These majestic creatures are at the forefront of stretching what it means to be considered human, and a testament of modern medicine to keep people alive.