if you want to keep your muscles and slim down then you need to work on 2 things1. Exercise2. Diets1. Exercises Mostly in Anaerobic forms(body building, Sprints, Free hands Exercises(calisthenics) etc)... anything which comes under the "Strength Training Program"2. Dietsthis depends a Lot on how you are now? Listen if you are overweight, then it's bit hard.start with strength training and 0.6-0.8 gm of proteins per pound... then later increase your protien intake... U need to get your protien levels right, first...If you are Overwiehgt n wanitng to loose weight n get good muscle tone then you should eat 0.6-0.8 gm per pound of body weight per day.(if You are cutting or loosing weight, dont go for more than 4 weeks)If you r not muhc overweight but just want to tone down muscles then your protien levels should 1-1.2 gms per pound of body weight /day.Now if you want to build up/bulk up... it can go up to 1.6-2 gms depending on your goalsPS: This is baiscally generalised version, but if you need to know how... then you need to get yourself checked by nutritionist and get ur goals...gettincrazyovercoding