Mike, Do this and ull gain at least 15 pounds.LIFT weights.. high weights , low number of lifts...EAT PROTIEN AND CARBS.bannanna and peanut butter sandwiches are a great weight booster, so is tuna fish.. before you work out about an hr before drink a protien shake (thats the best time)and right before you go eat a little something with sugar (candy bar) then at bedtime drink another shake .theres also alot of protien shakes out... id go to a local health store to find the best. Some taste like mud others are acutally great. Ull have to try them till you find one u like.BUT dont get TOO much protien because it can become toxic. also if u have cf diabtes try a protien shake with low carbs.. if not ENJOY the carbs!You wont notice yourself getting bigger untill about four weeks, then you will notice a slight change, then usually a huge change shorty after... total 6-8 weeks.I have CF and actually worked as a trainer at a gym . I was smaller than the other guys but WOW was I much bigger than before! And I was more cut than the other guys. (from what I heard at the gym girls prefer cut over bulk in most instances anyhow).Hope this helps you. OH and try talking to a trainer at a gym about a workout routine, but as far as nutrition Id use your own judgement. They wont know about cf i guarantee it and what works for them probablly wont for you. Remember you need much more nutrients than the average joe.