An apple a day keeps the doctor away. Many reasons why we should heed this advice. From bone protection, asthma help, lowering cholesterol to weight loss. There are 47 calories in an average sized apple, so an apple is a great snack, simply slice and bite. Apples are also a powerful source of antioxidants, including polyphenols, flavonoids, and vitamin C, as well as good source of fiber, and potassium when you include the skin. The apple skin alone provides two to six times the antioxidant activity of the apple flesh alone. So it is important to eat the skin to obtain the full health benefits of apples.