You want facts? How about basic thermodynamics? Fat evolved to store excess energy from food to be used during time of calorie deficit. It does this by storing 9 calories per gram of fatty acids. This means that it took at LEAST 9 calories of excess food to make that gram of fatty acids. Since this is energy and we don’t use fission this energy can ONLY come from food intake. Thus having hundreds of pounds of excess fat is absolute PROOF that one has overeaten for a long time.