Yep, you're depriving your body of nutrients it needs. There is no special formula combination of foods - you're losing weight because you're not eating enough calories. I don't mean to be harsh, but you're probably going to gain most of it back if you follow such an extreme regimen.
A lot of commercialized diet plans have a strict beginning that usually lasts two weeks. Atkins and South Beach have you cut out carbs for the first two weeks, in order to speed up weight loss and get rid of "carb cravings". The hitch is that you need to continue following the plan of re-introducing carbs back into your diet, or your weight loss may be unsuccessful. The Fat Smash Diet has you start out on a detox phase, where you eat fruits, veggies, beans, tofu, no meat, and no sugar. This lasts ten days. In all of these beginning phases, people usually lose between 5 and 12 pounds.
If you want to lose a small amount of weight, I've heard the Extreme Fat Smash Diet will do the trick. I don't personally endorse the FSD; it was the first diet that I tried, and I failed at it - IT DIDN'T FAIL ME - I FAILED IT - there's a difference.
The people on Celebrity Fit Club follow that diet and get great results ...and there's an entire board on this forum dedicated to it.
A Wacky New Diet
Lots and lots of people can lose weight in the short term. Keeping the weight off is the hard part, and quick-loss solutions where one eats radical combinations of foods don't really address that.
Just keep it safe and keep it sane. 
