I get like that too sometimes. Then I remember that I wear size 8-10 clothes, and so if I think I look fat, it's got to be psychological. I pulled a friend of mine on Friday night and he's told me that he likes his women to be fit and slim. He certainly wasn't complaining with my body though. And if I lost weight, ok I'd get into a size 8 every time, but then I'd probably want to get into a size 6 every time, and it would develop into a destructive cycle. I might also lose my 32D boobs, which are my best feature! And maybe this guy wouldn't fancy me if I lost weight.
He was also telling me about his ex girlfriend. He said he met her at uni when they were both in an athletics team together, and described her as slim and blonde, and stunningly attractive. Yesterday I asked him if he had any pictures of her, and he got one out. Not what I was expecting at all. From what he said, I was expecting someone really thin who looked like Barbie. Instead, she was normal sized, probably size 10 but not size 8, and very natural looking. He was right, she was stunning, but in a very understated kind of way.
So it seems men (or some men anyway) have a different idea to women of what makes a girl attractive.
Whenever I start to feel fat, or envy a really thin girl I see walking down the street, I remember these things.