There are plenty of reasons why an apple is a great go-to healthy snack. It's low in calories -- just 81 calories for a medium-sized version. But it's also rich in soluble and insoluble fiber, important for cardiovascular and digestive health. Fiber also helps keep you full longer, which makes an apple a great snack for weight control.

Keep the skin on your apple, and you'll increase its vitamin and antioxidant content. Almost half of the vitamin C in an apple sits just under its peel, and the flavonoid quercetin -- which may protect against cancer -- is only found in the skin. That extra crunch boosts the fiber content too.

My favorite varieties are Golden Delicious, Gala, Fuji and Honeycrisp, so I stocked up on a few of each.