Yeah, just because he’d like a snack doesn’t mean you have to give him one. Do you get a cookie every time you think “Mmm, I like cookies”? If I fed my dog everything he sniffs at he’d weigh three hundred pounds and need to be carried around in a cart. You’re the master.
We give our dogs carrots, apples, broccoli as treats. When I peel carrots or potatoes they get the skins.
Eh, I know my dog, and I have two, one is greedy and would probably gorge herself to death. One (the subject of this thread) is not, even if your dogs are, no offense, but every animal is different, and your pets eating habits aren’t my pet’s eating habits. He’s always gotten a certain measured amount of food per day, assuming he finished his meal from the day before, and suddenly his metabolism has dropped due to neutering, and no, I’m not going to just cut his food and think “too bad for you that you aren’t getting full anymore.” He managed to stay fit and trim for years. It’s not like the logic of things like not giving snacks has escaped me.
Thanks to all those who suggested foods. I’ll look and see what the calorie break downs are when I have a chance.
For the suggestion that I try “cat” well, my dog may have gained some weight, but he’s just on the edge of being a legitimate dog. I don’t think he’d be a match for a cat. 
Hmmm… exercise from chasing the cat, and (presumably) a lean protein snack at the end of it?
Or… if the dog doesn’t eat the cat… keeping the cat indoors, with a litterbox. Extra source of fur therapy, dog chases cat and gets exercise, relatively little litterbox cleanup duty (for you anyway… the dog will do the deed, ick!!)… win-win-win situation 
More seriously I had popped in to suggest canned pumpkin as a relatively low-calorie food, and somewhat sweet tasting if the dog likes sweets.
The pumpkin is out of stock in this area too, but I found some butternut squash cubes, and one or two of those per day might tide him over. We’ll see.
For those who were concerned he’s not exactly a ball with legs yet, and as a beagle who’ll be five this year, he definitely would be if we were raining food and treats down on him all day long for months or years. We’re just putting the breaks on this (going from 25 lbs in December to 31 doesn’t sound or look like too much, but it’s a 24% increase) before it gets out of hand.
This covers at least two of the reasons I won’t ever own a cat.
Have you asked your vet whether the weight gain is related to the surgery? A change in appetite can sometimes be a warning sign.
Have you tried frozen green beans? My dogs won’t touch them at room temperature but will eat frozen ones all day long.
My 114 lb. (and very tall) Lab Mix is currently pouting in a corner having been sucker-punched (sucker-scratched?) by the 12 lb cat. Even big dogs are sometimes no match for a fearless kitty. 
They didn’t say it was the surgery (that was my guess) but suggested just getting him on a diet, at this point, as he’s getting older, and his breed is prone to weight gain, and he recently had a full work up before they’d operate on him. He hasn’t had a change in appetite, he started gaining on the same amount he’d been eating.
I hadn’t tried frozen green beans, but that is a good point. Both of mine like frozen sweet peas.
Poor thing; after this story, I know my dog would be out of luck, then.
I assumed that when you said he was hungry more often that indicated a change in appetite. At any rate, I feed my adult dogs a weight control dog food. Feeding the same amount gives them fewer calories. Would that be a possibility?
What I meant is that he’s hungry more now because he’s getting less. He was happily eating the same amount he’d been getting without complaint until we noticed he was getting pudgier. I just looked and see that they do make a weight management version of his food. I’ve never seen it in stores, but I’m sure they can order it.