Oh gosh yes....you can go as long as you and your body feel is right. The juices provide all your nutrition, make sure you drink a variety of fruit juices and alot of greens. I am not as experienced as some fasters here but I would recommend a liquid vitamin mineral supplement along with the long fast. Just try to take care that it doesn't have alot of Sugar or honey in the formula, as this can jumpstart the appetite and cause cravings. Livingwater has been off the board here for a bit...but I know she has done a couple fasts over 100 days, with no problems. I am sure she will be back around here soon.