Is everything we eat completely digested and used by our bodies?

No, everything we eat is not completely digested and used by our bodies. The digestive system is responsible for breaking down food into smaller components that can be absorbed and utilized by the body. Some foods are more digestible than others, and the efficiency of digestion can vary depending on factors such as individual physiology, the presence of enzymes, and the composition of the food. Certain components of food, such as dietary fiber, may pass through the digestive tract undigested and contribute to stool bulk.