snacker
A person who often eats small snacks between meals.
A snacker is someone who eats snacks, especially frequently or habitually. If your brother is always grabbing crackers between meals or munching on apple slices while doing homework, he's a snacker. Some people eat three big meals a day, while snackers prefer eating smaller amounts of food more often throughout the day.
The word usually describes someone's eating style rather than criticizing them. Your grandmother might affectionately call you a snacker if you're constantly raiding her pantry for pretzels or cheese. Teachers sometimes keep snackers in mind when planning long field trips, knowing certain students will need something to munch on during the bus ride.
In casual conversation, calling someone a snacker can suggest they enjoy the social aspect of eating too. A snacker might be the friend who always has gum to share or keeps a stash of granola bars in their backpack. While the word can occasionally carry a hint of teasing (especially if someone snacks constantly), it's generally a neutral or even fond way to describe eating habits.