"Mr. Behrens, you must understand that the nutrients in food become various substances the body needs. Some become part of your body, but that process takes a long time. What you're describing is almost impossible."
Professor McGonagall had put her finger on the problem.
"All right, Professor. Let me ask it another way."
"If I were dying of thirst in a desert, turned a biscuit into a bottle of water, and drank it, what would happen when the Transfiguration wore off? By then, my body might have lost that water through dehydration. What would happen to the water still in my body?
"What would happen to the water that had already evaporated?
"Or suppose I had a fever and turned a glass of water into medicinal herbs. After I ate them, my fever went away. If the herbs then turned back into water, would I stay healthy, or would the fever return?"
Professor McGonagall was silent for several seconds. She looked at Will with an expression of admiration mixed with something more complicated. "According to Transfiguration theory, if enough time passed for the transformed food you ate to be completely replaced within your body, its eventual return to its original substance would not change your condition. It would be as though you had truly 'taken in nutrients' or 'cured an illness.'"
"Professor, you said that was theory. Has anyone put it into practice?"
Professor McGonagall began to explain.
"This was before Gamp's Law of Elemental Transfiguration was established. In 1412, a school of Wizards whose knowledge was passed from master to apprentice began a long-term study of the theory of Food Transfiguration—not only of food, but of Human Transfiguration as well."
"Human Transfiguration?"
"Yes. The two may seem unrelated, but they believed an Animagus, the pinnacle of Human Transfiguration, could