I think it depends on the person but for someone like me, it wouldn't change my view of you. It should be noted that I'm a very big stickler on weight. I take a lot of pride in my health and being overweight is the biggest turn off for me.
When I see a young girl (aprox under 30) who is overweight, whether she ends up losing the weight or not. I have to question her lifestyle and how she got that way. Your at prime age for your health so if you can't keep your weight off when your young, that tells me its going to be a constant struggle your entire life when it only gets tougher due to genetics.
Similar to the previous issue, I would be worried she is going to get fat again. Clearly she doesn't have the best genes, the best life style or both. If 10yrs later, life kicks in, she starts working more, has kids, etc. and doesn't find the same kind of time to hit the gym 5 days a week and gets fat again, its going to be a big issue for me.
I know I sound shallow, but its just my preference that I can't help. I just have zero tolerance for being overweight. I normally have very realistic standards of women, but this is one thing that is a real deal breaker for me. Maybe part of this is because I'm not exactly a huge guy. I'm short and fit (not buff, just athletic like a soccer player), so I need a small petite girl otherwise it just makes for an awkward dynamic. I don't want a girl who looks like she is overall twice my size.