I am a 43 year old male that has lost 30 pounds in the last 6 months going from 180 lbs. down to 150 lbs. I'm 5'11'' tall and my body fat is now at 8.5% versus the 20% that I was at when I weighed 180. I accomplished the weight loss through a combination of using both versions of P90X, consistent additional cardio workouts, and eating clean consistently. I simply tracked my calorie intake versus my calories burned to ensure that I had a calorie deficit. I am extremely lean now and I want to embark upon gaining 10-20 pounds of lean muscle. Should I simply increase my calorie intake of course only eating clean food and then increase my weight lifting while cutting back on my cardio. I'm concerned about my waist getting bigger during this weight gain but I do ab work 3-4 times a week and also a fair amount of core work through the P90X program. Also, I do eat plenty of protein and good carbs. My calorie intake currently is about 42% protein, 38% carbs, and 20% from fat. Any advice or guidance would be greatly appreciated.