Because Dr. S's IF1 was made for us in the 80s, 90's +. For those of us who grew up with McDonald's, etc. Problems Dr. C didn't have to face.
I still love IF1 and use it ocassionally. At this point its around for me when you just feel like you want to clean out really well.
Dr. S was on it everyday for 12 years and speaks that the senna problem is overated. He says - would you rather take some concentrated food product (herbs...) every day or would you rather be at increased risk for cancer, etc. (constipation).