Eating and digestion
Food contains the body's energy sources and the building blocks for maintenance and repair,as well as being enjoyable and,for some,even a hobby.When you swallow,food travels along the digestive tract,from the mouth,down the gullet(oesophagus) to the stomach,and then on to the small and large intestines.As this tract is relatively large,it has been possible to study the mechanics of digestion since ancient times.Detailed knowledge about the chemistry of digestion,and why the body needs certain types of foods to maintain good health,is relatively recent.Even more recent is a drastic change,particularly in the West,from the age-old and varied human diet of fruits,vegetables,nuts,and some meats,to fast foods,and modern processed foods that are rich in sugar,fat,and salt.So while the digestive system remains stuck in the Stone Age,it is fed by the Space Age.Current nutritional advice now encourages people to try to return to a more natural,belter balanced diet.