Duckers,
listen to EmperorNero, cuz he knows what he's talking about. as a former premed student (i'm not doing med school thing anymore), i had to learn all this metabolism stuff backwards and upside down. glucose (simple sugar) is the most readily available form of energy your body uses. during more vigorous exercise, your body uses up fat. protein is the last energy storage your body taps into. when you're starving yourself like this, just likeanorexics do, your body metabolizes protein into glucose. this process is called ketoacidosis, and plainly put, is bad thing to do. besides having a very bad breath as a side effect (and believe me, you will), it can do a number on your body and its organs. if i'm not mistaken (it has been several years since i learned all this), your vital organs can also be adversely affected, as EmperorNero stated. all that anorexics suffer from, you can suffer from too if you continue this on regular basis, such as kidney failure. many anorexics go into shock, because of the elevated acidic level of their blood as a result of ketoacidosis.
when you starve yourself like this, your body kicks into its 'premitive caveman' mode. imagine your ancestors many many years ago, living in caves and dependent on what they can hunt and scrounge up. between huntings, cavemen had to survive for many days, if not weeks, without food. their body went into 'survival' mode, and hung onto every single ounce energy in the form of fat, in case energy is needed later on when they spot mammoths, etc. body doesn't want to burn any unnecessary energy, and that's what your body wants to do right now. men have bellies, because this is where male body stores fat. cavemen during 'good times' stored fat in their bellies, to use as energy reserves. us men have our cavemen ancestors to thank for our bellies.
you're losing/maintaining your weight because of the salad diet, not because of your week-long fast. exercise is the best way to maintain your weight, believe me. i used to wrestle in high school, and i would eat anything i wanted and yet still maintained 3% body fat. good thing all my favorite foods did not contain sugar or much fat.