There is probably a minimum healthy weight for any individual and you are pretty near that. If you are determined to loose weight, you will have to severely restrict your intake of something. Most individuals can drop some weight, while retaining most of their lean body mass by eliminating all carbs for a short time (2-6 weeks), and then maintain that lower weight by keeping their carb intake very low, and only eating low glycemic index carbs. One way to reduce your carb intake is to have only a protein shake for breakfast and lunch and meat and vegetables for dinner. Or if you really want to get radical try the velocity diet (google it). It's basically ingesting nothing but protein shakes and vitamins for 30 days.
Remember, if you reduce your body fat level too much you are likely to affect your hormone levels to the point you stop menstrating and experience rapid loss of bone density, so be careful and consult your doctor if something does not seem right.
