Crunchy, sweet and juicy, green seedless grapes satisfy a multitude of cravings, which may be why everyone like them so much. With 104 calories per 1-cup serving, green grapes make a healthy and natural low-calorie snack. The 1-cup serving of green grapes fills you up and satisfies hunger, which helps keep overall calories and ultimately weight under control. Grapes contain a substance called resveratrol, which is a natural compound that protects the fruit from environmental stress, fungal infections and ultraviolet radiation. Resveratrol also works to protect human health. As an antioxidant, it may protect your cells from free-radical damage and lower your risk of heart disease by preventing blood clots and reducing inflammation.