My aunt is actually morbidly obese. She has no eating disorders, has been active (she competes in equine endurance races) and eaten healthy all of her life, she eats fast food maybe two or three times a year. She has thyroid issues and is on medication for it, her blood pressure, and cholestoral are great. Why is she morbidly obese? Even her doctor doesn't know.
My sister is also obese. She has always been this way. Once again, she eats fast food a few times a year if that. She's active ( a live in nanny and also trains horses) also has thyroid issues and is careful with her diet.
I have to say going out with them and seeing how people respond and what they whisper... it's easy to say 'oh that person is fat because they are a pig and never stop eating' but it's not always the case. It's easy to believe the stereotypes and what you see on tv, people stuffing their faces and eating like no tomorrow but the reality is usually much much different. You're pretty much damned if you do and damed if you don't. If you buy 'normal' food they say you eat too much of it. If you buy 'diet' food they say that you're only eating that in public and in reality you stuff yourself at home.... Heard it all.