Let Nature decide for you, would be my advice. We all have an optimum level of body weight based on our height, bone structure and metrabolic rate which is natural to us. Don't start mucking around with diets. From what I've deduced, it's one of the worst things you can do. If you want to trim down to your optimum shape and size, excercise sensibily, eat good food and let nature gradual shape you into the shape you're supposed to be.
Four or five decades ago there were very few overweight people; today, its about forty-percent or more people who are carrying far to much fat. We already know the downside of that down the track.
Excercise across a wide range: aerobics, pumping iron, yoga-type stretching are all good. This will keep your breathing, muscle strength and body suppleness in good condition. Fitness makes for a healthier you.
This does not mean you cannot enjoy 'some' junk food, or have a beer or three or a glass of wine. It does mean that 'in the main' you stick by fresh, healthy foods that will feed and nourish that body you want to sculture.