If I had water and celery/carrot sticks for a week, how much weight would I lose?
You need to eat 3500 calories less to lose one pound. So if you have been eating about 1500 to 2000 calories a day and you ate 0 calories a day for one week, you might lose 3 to 5 pounds. You would have headaches, feel tired and nauseated, might have fainting spells and would not function well for the week. You would also lose muscle mass as your body would rob protein from your muscles to function. Some of the weight loss would be water loss due to the way your body processes protein. After the week when you started eating again, you would gain back 1-3 pounds. Eating 1000 calories a day would result in losing 1-2 pounds per week. Those pounds would stay off, not be due to water loss. So the best way to lose weight and keep it off is to not have the week of no food but to start right away with eating 1000 calories per day. If you ate 0 calories a day for one month you would die. Humans can survive for about 3 weeks with no food.
