I have NOT had any negative side effects (my bowel movements stayed the same). I have always tried to do the Take Off Phase on the weekend. I use the weekend as my time to gear up for what is ahead of me. Such as the meal planning, food cooking and the proper food shopping.
In the case of having loose bowel movements make sure you are diluting the juice the way it is described. I know of some people (my husband) who drank the Juice straight from the bottle without diluting it and had big problems with diarrhea.
They say that you can do the Take Off Juice every 2 weeks but I only repeat the Take Off Phase when I hit a plateau in my weight loss and I need to jump start it again. Once the Take Off Phase is over I start following the color plan that was given to me.
On a personal note I have been instructed by a counselor when when I hit a weight loss plateau to do the Take Off Phase for two days and then replace a protein and carb for their slim down shake for another two days which helps tremendously.
I really enjoy the Take Off Phase period. Since I have followed the LAWL Plan on and off for so many years I have a couple versions of their Take Off Phase. I used the Take Off Phase which allowed me to eat unlimited amounts of protein and green veggies. Also there are versions of the Take Off phase in which you can have oranges instead of the Juice.
Let me know if you need more information
~~~ I hope this helps