just about a month ago my hole family came down with the flew . Soon as I heard they were all getting sick I started a 19 hour dry fast. 7 days past and I still wasn't sick yet , they were all just starting to get better and BAMM! they all relapsed so I did a 23 hour dry fast this time and still never got sick. just my personally experience with dry fasting , so yes I do most definitely believe in its effect on the immune system. and yeah that's no Science but how would anyone explain it? oh yeah and it was the first time I ever escaped getting sick.