Hi Mr. Silver - 10lbs of muscle is alot to loose. Your top source of pure protein is egg WHITES! Not the yolks. Keep to chicken, turkey, lean cuts of red meat but only every once in awhile. Go to your local health food store or supplemental store like bodybuilding.com and inquire about quality whey or casein protein powders that actually taste good but are low on the fat content side. WHey protein is assimilated into your body at a more rapid pace and casein protein takes longer. Casein is good to take before you go to bed to support muscle during the long night of no food consumption and to help recovery from a day endurance riding. Good luck to you!