As someone who has dieted a lot and has has problems with weight I can tell you that not eating will actually make you gain weight. The reason is, your body thinks you are starving yourself, so when you do eat, whatever you eat automatacally gets stored as fat so the body can live. I gained about 20 lbs when I did the eat once a day thing. Trust me it does not work. The best thing you can do is eat 5 small, healthy meals a day. You want to keep the fire burning (you metabolism) so you can burn fat. Take a walk or a jog once a day, and start eating healthy meals and snacks all day long. In no time you will actually notice that you have more energy and you are losing weight.
1 Additional Answer
The amount of weight your body will lose if you stop eating depends on your personal metabolism. But you have to realize that once you start eating normally, the weight you lost can be gained back just as easily. See when you stop eating, your body goes into survival mode and begins munching away at the fat you have stored for energy. If your concern is weight, there are more healthy ways to go about losing it than starving yourself. You can find more information here: www.weightlossforall.com