If I'm getting my protein and other nutritional needs met through a balanced diet, I don't worry about what I snack on during a ride. Usually I crave coffee and donuts. So that's what I look for. If I'm doing a hard workout 20 mile ride, or a longer more moderate 40-60 mile ride, I don't care what I eat as long as I can digest it.
My physical therapy appointments are a 6 mile round trip on a hilly route. Perfect for interval training, 15-20 minutes each way depending on wind and traffic. So I'll sometimes indulge in coffee and a donut at Dunkins before the return trip home.
Whey is cheap, so it's getting easier to find cheaper supplements with a bit of added protein. Seems folks are finally catching on that overpriced whey protein supplements were a bit of a ripoff. I can often find Clif bars or something similar for 50 cents or so.
I'll often carry individually packaged snacks. Even vanilla sugar wafers, three per single serving, wrapped in plastic and sweat proof. Costs a whole dollar for a carton of the sugar bombs at Dollartree.
Not sure if that's sound nutritional advice, but I've lost about 10-15 lbs since this time last year. Mostly that's from cutting way back on the beer. I don't keep it at home anymore. And I drink one or two a week or less often at a restaurant or pub with friends. I don't seem to enjoy it as much now so it's been fairly easy to cut back. But I'm not giving up coffee with cream and sugar.