Since I'm pretty early game and don't have too much stuff yet (though I could probably open a housewares store) I made sure to buy the cheapest things he can consume from vendors in case he needs a snack. I'm also the type to get hangry so maybe I got a weak spot for his condition.
Yeah, but luckily only a maximum of thrice, so you should have no problem getting enough crappy but eligible items to feed him that you don't have to give him any you might actually want..
That really caught me off guard! I assumed it would be one magic item snack per long rest, so I was very sparing with those and gave Gale a pouch specifically for hoarding lesser magic items in... and then he never ate another one!
Extra warning in case the tags don't work for you: Late Act 1 Spoiler coming up
late act 1 spoiler
He'll stop asking after 3 times or near the end of Act 1 (whichever happens first) when Mystra "pauses" the whole thing to make him pretty much a kamikaze nuke who's supposed to detonate himself later in the game
Are you sure you have items in your inventory for it? There's a message at the bottom of the description if it works (just in case someone didn't see it, says Gale can consume it on its own line). I've seen it where it shows what everyone is carrying that he can consume in like separate selection / inventory areas by people where it just shows the consumable items. I've only done it a few times though so could be a bug. I don't think it'll show if it's in your camp inventory either, current party only is my guess. I made a warlock so I don't usually have him around much and only have done it at camp.