It's true in a lot of cultures. I know in pre-colonial Hawai'i, being huge was attractive. I hear it was true in parts of Africa, too. It's not true in the states just because the bar isn't that high to get 2-3k calories per day. I think it's generally true that standards of beauty follow whatever implies a higher standard of living. Look at America today: facial and hair complexion to show quality, not just quantity, of food; muscle tone and tan to show spare time out of a desk job doing exercise; and of course flamboyant displays of money, the ultimate objective measure of success.