I'm a student so I know exactly where you're coming from. I buy everything raw and make my own meals. I spend Sunday cooking stuff up, shoving it in tupperware boxes and then taking it to uni with me for me to eat in breaks between lectures. I also carry around a 'smart shaker' that lets me carry two shakes with me which are good for meal replacements.
Commercial shakes are quite expensive so I buy all my stuff from a website similar to
www.myprotein.co.uk (I live in the UK) which distributes raw supplements without any of the added stuff. So you can buy a year's supply of amino acids for a very good price along with instant oats and whey protein which you can mix into a shake for a great tasting meal replacement that will keep up the calorie count and give you vital nutrients for gaining weight.
This is just what I do along and a great diet combined with a proper gym routine have let me see great results!
Hope this helps buddy.
