With RC you will have to feed more, so while 4.5 cups might seem like alot it might not be enough. Delgado ate Fromm LBP and he ate between 4-4.5 cups and he's always been a pretty ideal weight.
If you're struggling to add weight on then either up the kibble slightly to maybe 5 cups and do snacks. A little raw chicken, turkey, or beef can help fill him and add calories but in a healthy way
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 5 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010