skip the diet and really make an effort to change what you eat. like said above hit a high protein, low carb, with a moderate fat intake.
go over to bodybuilding.com and read the nutrition section in the forum. learn how many calories you need to maintain your weight then you can change your intake to met your goals. educate yourself on how protein, carbs, and fat are used by the body.
you need to find out what works best for you.
BMR calculator:
http://www.caloriesperhour.com/