Your digestive system shuts down during a fast.
That is why it is important to practice DAILY bowel cleansing. You could do laxative tea morning and night, or the salt water flush or an enema. You have to do one of these. When you fast, your body does its cleansing work and dumps the toxins into the colon. If you do not clean your colon, the toxins will be reabsorbed and you will autointoxicate. This is dangerous especially if you are overweight, because the toxins are trapped in the fat tissue and are thus being released quickly when you fast. So you will get sick and feel dizzy, nauseous, etc, something which several fasters in this forum have experienced.
This will also slow down your weightloss because your body has to concentrate on dealing with these same toxins again instead of moving on to new clean up work and thus helping you to shed additional pounds at a good rate.
Please do your research on bowel cleansing and other aspects of fasting. Read the FAQs in the other fasting forums here on curezone.
Yes, you want to shed weight quickly. Bowel cleansing will help you do it and will keep you healthy. It will also help you avoid some other side effects of fasting, such as skin break outs and rashes, fatigue, etc.