Yes, die-off reaction - or you don't want the yeast to die??? :o) It is explained on numerous web pages how yeast overgroth can effect our body - they are releasing toxins, that's why many people with serious yeast infection feeling foggy and tired all the time. And it's not enough: when you take action and they die, that puts some kind of toxin in your body too - but at least the reaction is temporary (for me it was bad for about a week or so) and then you feel better. So instead of medicine doing damage to your kidneys and liver and other organs, you have a choice to go slower (and healthier!!!) - and the price you pay is this die-off reaction. That's why they recommend drinking lots of purified or spring water and eating tons of raw veggies so they can help your body get rid of the bad stuff.
Another thing is that some of us don't have a choice: I have C.albanicans infection and this particular kind (there are a whole bunch of different ones even in this one group) can not be successfully treated by "regular" medication. The doctors tried every available medicine until I have found a web page by the government(!) that stated that some of the C.albanicans have developed resistance to modern medicine and impossible to treat - it gave me an answer why I was still sick and getting worst after 2 years of different treatments.
I could really tell the difference after about 2-3 weeks I started my regiment of herbs: I had more energy, I was not foggy and tired anymore, my Depression and negativeness was much better - it was all great. So bad I could not do the diet longer, that was the missing link. Now I'm ready to do it again and this time I'll finish them all!!! ;o)