I can't say in terms of weight loss, but one important factor is that if you eat a low-calorie diet, you will suffer from hunger throughout your diet. Also, Water Fasting is not easy to do, supposedly. I never did it but people doing it seem to have very little energy, not enough to go to work for sure. I would advise a juice fast. It provides you with the basic energy you'll need to go through your days, you'll still lose a lot of weight, and you won't be hungry.