Jake is pretty much already in good shape enough that makes sense for his character. He can "canonically" carry a gatling laser without power armor from that school all the way back to his workshop, and this was AFTER being tortured and beat up for who knows how long. So i'd say he's pretty fit. Only companion bigger than him really is Paladin Danse. He is somewhere in between Preston and Danse.well you need to fix that come on like everyone knows in the post wasteland America the only thing left to safely eat is protean powder