NO NO NO!!!! Do not eat only 800 calories for one week. You should eat more that 800 calories in a DAY!!! Try to eat about 1300-1500 calories a day. Mabey even a little less than that if you are not too active. But you need to try to excersise just a little bit! Hope I helped! ~Gina~ P.S. If someone named J_Lynn replies do not listen to her. She has a attitude and has no idea what she is talking about.