I bought an Amphipod waist pack with two bottles (total 21 oz) and a carry pouch on it. I got the largest size so I can shove it down around my hips. I cannot stand anything around my waist. It makes me nuts, dunno why, but it does. Fortunately (?!) most of my fat is around my belly and hips. If I shove the belt sort of below it...it stays put. Pretty much. I may try a running Camelbak back pack. At $40 a pop, it's expensive to keep trying these things out!