Avocado provides a good concentration of calories, plus antioxidants, fiber and heart-healthy mono-unsaturated fats that help kids’ bodies absorb the vitamins in veggies. To make, just mash an avocado (kids can help!) and add diced tomatoes or a spoonful of salsa and a squeeze of lime juice. Serve it with baked tortilla chips, pita bread, bell pepper sticks, carrots or sugar snap peas. (You can even make a fun face on the dip by adding two cucumber slices and two pimento-stuffed olives for eyes and bending two chives into the shape of a mouth.) Get your little one involved, too. “When they’re part of making a snack, they’re more likely to eat it -- especially if it’s something new,” says Krieger.