Will I lose weight if I don't eat anything for 1 week?

 
Your body needs energy to function properly. This energy is provided by the food you eat. Any excess calories are stored in the body as glycogen or as fat. If you do not eat anything or if you eat less than required, your body will start to obtain energy from these stores. Once these stores are exhausted, you could lose even lean muscle as the body attempts to survive. The rate at which these activities occur differ from person to person. So while you _will definitely_ lose weight if you starve for a week, the amount of weight loss cannot be predicted. The body’s starvation mechanisms are not efficient and can give rise to products that can be harmful to your organs. In addition you will also develop nutritional deficiency disorders. Starvation _is not_ a good idea for losing weight. You should adopt a balanced protocol of controlled dieting and exercise.