Apples contain high amounts of fibre that helps you feel full for a longer time. They have pectin that binds with water and restricts the amount of fat that the cells absorb. Apples have high water content and are low in calories. They have a low glycaemic index and are great fat burners. Eat one or two a day, a little before meals, and you will be able to control your portion sizes. The Granny Smith green apple variety has more insoluble fibre than other varieties.