What happens when you eat?

Answer 1

Between the sensations and chewing in the mouth, digestion is triggered and starts with the physical breakdown of food through the chewing motion, and enzymes in saliva. The stomach helps with immunodefense and further physical breakdown of food. The lining of the stomach also helps to absorb and excrete water until its contents reaches the proper consistency, at which point the food passes into the intestines.

In the intestines, bile is excreted to break down fats, and nutrients are absorbed through the intestinal wall. Before leaving the body, a healthy digestive system reabsorbs most of the water before the once-food is passed back out of the body.

"Nutrients" and "vitamins" are terms coined for very important chemical compounds, most of which cannot be replicated by the body. Most critically are carbohydrates, which are converted into ATP for use in metabolic processes like the Krebs Cycle.