I think my kids will kill each other with three sweets a day (plus breakfast sugars)....so I went through and made a cheat sheet of "places that have a snack that are slightly healthy". Also included frozen drinks and coffee, because it's nice to have something refreshing during the day.
YMMV...
MAGIC KINGDOM
Main Street Bakery: Yogurt Parfait, Bag of grapes, Fruit Salad, apples with caramel dip, celery/carrots with ranch dressing, Smoothies
Main Street Confectionery, Chocolate covered strawberries, Caramel apples
Enchanted Cove/Fantasyland: Lemon & Rasp Slushies, Iced Cappuccino
Scuttles Landing: Pretzel, Frozen pop
Sunshine Tree Terrace: Slush, Chips, Coffees
Caseys: Side of chili, Side of fries
Auntie Gravity's: Soft Serve, Floats, Smoothies, cappuccino
Lunching Pad: Frozen Coke, Carrot and Celery Sticks with Ranch Dip
Liberty Square Market: Grapes, Mixed Fruits, Carrot/Celery Sticks, Baked Potato w/cheese
Sleepy Hollow: Coffees
Pinocchio Village Haus, Figaro Fries
EPCOT:
England: Chips (Fries)
France/Boulangerie Patisserie: Ham and Cheese Croissant, Coffees
France/Crepes des Chefs de France: Crepes, coffees
Germany/Sommerfest: Soft Pretzel
Japan/Kaki Gori: Shaved ice
Liberty Inn: Frozen cokes
Norway/Kringla: Jarlsberg and Leek cheese soup
Promenade Refreshments (near Canada): Popcorn, Pretzel, smoothie, slushie
Sunshine Seasons: salads, Fruits
USA/Fife & Drum: Frozen Lemonade
AK:
Anandupur Local Food Cafes, Pork Egg Rolls, Chicken Fried Rice
Flame Tree: Corn Muffin, French Fries, Onion Rings
Harambe Fruit Market: Fruit Cup, Watermelon, Grapes, Pineapple, Pretzel
Safari 12: Frozen Orange juice bars
Pizzasafari: Breadsticks
DISNEY STUDIOS:
Starring Rolls: Coffees
Min & Bill's Dockside: Pretzel, Shake, Frozen Drink
KRNR, Frozen Lemonade, Smoothies
Writer's Stop: Coffees, Fruit Coolers