The apple is a natural food that has a short shelf life the apple will soon decompose on its own where the potato chip has preservatives so it will stay on the store shelf longer to be sold. When we eat foods like apples that are natural foods. The body can easily recognize these foods and take the nutrients from these foods and easily recognize waste and get rid of what has no nutritional value and send the nutrients throughout the body.
Now when we eat man made foods like potato chips our body has a hard time recognizing these foods but dose not want to get rid of the food through waste because you eat it so it must be nutritious food to fuel the body? However there is the preservatives that provide a shield over them and the digestive system can't break it down. It try's to but just can't then more chips come into the stomach and the body can't process the chips so it stores it in a fat cell to get to it later. But more and more of these foods are eaten and the body just can't process it fast enough so these little fat cells get packed more and more and more giving you that round look you don't like make us fat.
Stop eating foods that are man made and eat natural foods that come from the ground. Your body will know what to do with these types of food so eat them up in small quantities.