Answer
A person on a bread and water diet for three weeks would be undernourished. In addition to being susceptible infections such a person's body would not be able to rapidly, and efficiently repair damaged tissues. Nutrients needed for tissue repair would include essential vitamins and proteins that a bread and water diet would not supply.
Work Step by Step
Vitamin C is necessary for the of repair damaged blood vessels : Vitamin A is needed for the health of epithelium; amino acids are necessary for the synthesis of proteins for tissue repair. A bread and water diet supplies fluid and carbohydrates , and maybe some lipids. In some cases, where the flour is enriched or fortified with minerals and vitamins, some of these micronutrients may be obtained from the bread. But the amount of proteins need in a healthful diet would certainly not be available in this diet.
