If you ask a man what is the most desirable thing in a woman's body he will say her curves. Hovewer, the answer is: "It depends". Some days ago I was at he gym doing aerobics. The instructor asked a lady: "What is your weight and height?" She answered:"I am 52 kilos and my height is 1,70cm". The instructor said that men like curvy bodies and that the best combination for a lady is weight: 54-57 kilos and height: 1.65cm. He kept saying that we were there to fix our body for men and men like J-lo bodies rather than very thin.
The issue here and as I see it from my point of view is that women should be as healthy as possible. Very thin or very fat are the two extremes. They should exercise drastically and systematically and eat healthy. It takes time but it worths the try. Healthy bodies are those that are vital, vigorous and sharp. A combination of exercise and healthy food and drinks can bring the desired results. So, the answer is you are ok with your body when you feel ok inside and outside.
However, I have a question for all men to finish with: Men's preferances of the opposite sex is like scottish shower: One day they like thin women, the other day they prefer curvy, once blondes or chestnuts, short or tall and the story goes on!
So women: You should feel good with your body and soul and let men deal and take care of their dilemmas! It's their problem! We cannot satisfy all desires!