What's this movie called?

I watched a movie on TV when I was a kid. The movie is probably made in the 1990s. It is about a normal guy, probably fat, who undergoes intensive physical exercise with the help of his sister (I think so, but not sure if she is his sister) to get in shape. Finally he becomes so fit and good-looking and finds a pretty girl and kisses her. I remember the ending was something like the sister looked through a binocular to watch the man kissing the girl (lady).

Thanks for your quick responses. Unfortunately I checked all the titles you suggested only to find out they are not what I look for. First of all, the movie was made before 2000, I am pretty sure of that. Then, the guy is a white, the woman is white and the dream date is a white too. Well, I can't remember the details but I am very sure that the main character - the guy is a white male. Thanks!

Is this it? "Don't Tell Her It's Me," a.k.a. "The Boyfriend School," made in 1990, with Steve Guttenberg as the guy, Shelley Long as his sister, and Jami Gertz as the dream girl.

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