When I go on ops of more than 15 minutes I have my Triple Tactical Twinkie Pouch attached to my vest.
It squishes them a little, but that just makes them higher speed-lower drag!
I like the ones with the red and the coconut (twinkies, not pouches-I only eat the pouch if I'm out more than a half hour).
Also use a 6 gallon camel back that I had custom made to hold diet coke.
I need to get in touch with his personal trainer....