Change your behavior first - feelings and beliefs will follow that. Act as if your body is acceptable and over time you will begin to believe and feel that it is. A man with quality character is going to look for a woman of the same. Your looks, which will change over time anyway, won't impress him near as much as your character. The more beautiful your spirit becomes, the more beauty will shine through you, as opposed to being outwardly beautiful with nothing inside but chaos.
Most men see physical beauty differently than our culture portrays it.
Most would say the models are not that beautiful. The standards for women are adopted by and perpetuated by women. If you don't think you are an acceptable person the way your are, changing the way you look is not going to fix that. It should always be for health. If you are going to try an exercise or diet program, be sure to use a knowledgeable professional for accountability and balance.