Answer:
The statement means that the human digestive system can adapt to extreme diets in order to survive. For example, carbohydrates can be broken down into sugars and used for energy. But when carbohydrates are not available in the required amount, it can also break down fats to provide the body with the required amount of energy. This explains why Deb has enough energy to keep going, even on her extremely limited diet.
Step-by-step explanation: