I feel the same way when I see fat women. Why, oh why do women get fat? When being attractive is her biggest card in the dating game. It is important for men too, but women see men's attraction as a combination of many things, looks but also social status, money, career, personality. All the things needed to protect and provide for her and her offspring. But women are attractive to men primarily because of their looks. It comes from our instinct to find healthy women who can bear children. And because men evolved to be quickly aroused by the visual, as these men passed on their genes more than the rest. The woman needed to display signs of youth and health: slim body, small nose and ears and a non-elongated face (as these grow with age, big eyes, lush and long hair (sign of health), youthful voice and laughter, a certain hip-to-waist ratio, smooth skin ... slim body! It's not so hard, for Thor's sake. Just don't eat those potato chips. I don't.
But I digress.