How much weight can one lose in 2 weeks using a lemon diet, eating no carbs, exercising, and waterdiet?

Don't try it: Never try to lose more than 2 pounds per week. Your body needs 40 essential nutrients every day: 13 vitamins, 15 minerals, 10 Amino Acids from protein and 2 fatty acids. If you do a fad fast like the one you describe, every day, some cells in your body will die of starvation. Use a reputable meal substitute formula like ensure, boost or glucerna, instead.