Read this article about Brazilian yogurt advertisements.
This is one of the worst ad campaigns I've seen in a while. The fact that they're so overtly playing into the confidence issues of their target audience is just beyond the pale. American advertisers also play into the fact that many women seem to feel the need to diet down to Nicole Ritchie size. But they do it in a more subtle way - focusing on being healthy, enjoying their food (think those yogurt commercials with the two women discussing how good the yogurt is "shoe shopping good" "first kiss good" etc). The ads here are focused more on women getting fit, slimming down, and eating right for their own well being. A process of self improvement.
These Brazilian ads externalize this, they make being skinny a question only of pleasing men. It makes a woman's self-worth dependent upon what a man thinks of her, rather than asking her to be healthy for her own sake. And honestly, those pictures weren't that bad! Especially American Beauty. She just looked full figured.
What really irritates me is the assumption that (1) men won't be attracted to you unless you weigh 100lbs, (2) all men are the same, (3) men won't like us unless we're slim.
First of all, there are plenty of healthy and happy women who aren't beanpole thin. Some women's body types are just naturally more voluptuous and it is unrealistic to expect everyone to conform to the same standard - some people will achieve without batting an eyelash and others will bust their asses trying to squeeze into that size 8 and not be able to enjoy because they're always focused on what they aren't (instead of what they are).
Assumption two - it's just as ludicrous to assume that all men have the same tastes as it is to expect all women to conform to the same body shape. Some men like round women, some like voluptuous women, some like slender women, others like petites, and others like tall women. It's all a matter of taste, environment, and that hard-to-define sense of attraction. And, at least for most of the men I know, I think they would prefer a women who wasn't model thin if it meant she was more comfortable and confident about herself.
Assumption three - men won't find us attractive unless we're slim. For both men and women equally, I find confidence to be much more attractive than whether someone is a size 6 or 12 (or whatever the equivalents are for men's sizes). I've met slim people who are so focused on their weight, or their clothes, or their makeup, that that talk just dominates their conversations to the detriment of all the other (non-self-centered) topics out there. Men sometimes really appreciate a woman who can hold an intelligent conversation.
I think the more important thing to focus on is being healthy. If you eat healthy foods in healthy portions, exercise to maintain your cardiovascular and respiratory health and get enough sleep, you're already on your way to a healthier mindset. And if you happen to weigh more than is the average but are confident about yourself, then there will always be men would will be attracted to you.
One final thing - forget the idea that you have to eat certain foods or be a certain way because of what men (or women) will thing. What's most important is to be happy with yourself and create your own sense of identity. If you do that, you have more to bring to a relationship and less likelihood to feel like your worth is pinned on what other people think of you.