Certified Dietary Manager (CDM) Practice Exam

What does mechanical breakdown of food involve?

1. Chemical digestion of nutrients

2. Physical breaking down using teeth and muscles

3. Absorption of nutrients in the intestines

4. Secretion of enzymes in the stomach

The correct answer is: Physical breaking down using teeth and muscles

The mechanical breakdown of food specifically refers to the physical processes that occur in the digestive system that prepare food for further digestion and absorption. This involves actions such as chewing, which is performed by the teeth, and the movement of food through the digestive tract, facilitated by muscles. These processes break down food into smaller pieces, increasing its surface area and making it easier for enzymes to act during chemical digestion. In contrast, other options such as the chemical digestion of nutrients focus on the enzymatic processes that break down food into absorbable molecules, which is a different aspect of digestion. The absorption of nutrients in the intestines deals with how the body takes in the nutrients from digested food, which occurs after mechanical breakdown has already taken place. Lastly, the secretion of enzymes in the stomach refers to chemical processes that aid in digestion but do not involve the physical breakdown of food itself. Therefore, the correct answer accurately describes the physical actions integral to mechanical digestion.