If your belly is huge and your legs are 30 inches wide Are you fat?

Fat, yes. Obese, almost certainly. Morbidly obese, very likely. If your BMI is between 35 and 40, with your weight more than 50% higher than the "optimum" (healthy) weight for your height and age, serious effort needs to be devoted to eliminating the excess weight, or you will suffer health problems, chronic pain, and a shortened lifespan.