Medical fact: a diet high in fat, sugar, animal products and salt (sodium), and low in fibre, vitamins and minerals is linked with cancers of the breast and bowel, and heart disease. That describes an average McDonald's meal. Chewing is essential for good health, as it promotes the flow of digestive juices which break down the food and send nutrients into the blood. McDonald's food is so lacking in bulk it is hardly possible to chew it. Even their own figures show that a "quarter-pounder" is 48% water.