What will happen if I don't eat for 1 straight week?

This is very unhealthy. As your body runs out of energy, it will begin self-cannibalizing itself by eating muscles and other lean tissues of the body. Low blood sugar results in a faint feeling. Fasting can result in depression, irritability, weakness, fatigue, and a sick feeling as well. It can also result in rapid loss of water, sodium, and potium, which decreases blood volume and results in low blood pressure. It also loads the body with metabolic wastes. Please don't do this.