The fiber in one large apple provides you with a wealth of benefits. In one study, published in PloS One, adding apple fiber — a water-soluble type called pectin — to the diets of rats lowered their intake of food and helped decrease weight and body fat. The researchers concluded that apple pectin supports satiety and weight management. Getting adequate fiber also assists with bowel movements and keeps you regular and may improve your cholesterol levels, lowering your risk for heart disease and type 2 diabetes. There is some evidence, too, that fiber may help protect you from colon cancer, although more research is needed. Men need 38 grams of fiber daily for optimum health, and women need 25, so just one large apple will satisfy 13 to 20 percent of your daily requirement.
Apples are rich in antioxidants such as vitamin C, which help fight off free radicals, molecules that can damage DNA and make you susceptible to illnesses such as heart disease and cancer. A review of studies, published in the Annals of Oncology in 2005, reported that eating one or more apples daily helped protect subjects from many different types of cancer, including esophageal, breast, colon and ovarian. In addition to vitamin C, apples contain antioxidant phytochemicals like quercetin, catechins and chlorogenic acid. In fact, the antioxidant activity of the compounds in apples is higher than that of many other fruits, such as grapes, strawberries, pears and oranges.