I don't really have the time to work out at a gym but i recently got a new more physical demanding job a about 3-4 months back where I do alot of walking/heaving lifting and various other stuff. Since I started working in this field I've noticed some muscle and strength gain. Now I want to enhance it and get a little more muscle mass. I'm guessing lean muscle mass? I don't want to be really big bulky but a good amount of mass. Can I do this with a good diet? I can probably go to the gym on my days off but between working in the mornings and getting off at 5 then going straight to school and home by 11 they're really is no chance for me to go to the gym. Also what would be a good diet but kinda cheap as I am a student and funds are limited. Also things that I can pack and take as a lunch like proteins bars and such cause I literaly don't have the time to go home between work and school to cook. Anyways thanks for the help. Also, I'm 6' 2 and about 190-200lbs.