The cayenne helps to keep the metabolism high but there is not reason that you shouldn't add another tablespoon of maple syrup to your drinks to raise calorie intake. If you are drinking 12 lemonades with 2TBS it is about 1400 calories so just add more maple syrup more.
Burroughs suggests this to those underweight or those looking to maintain weight. However, many toxins are stored in our fat cells and burning fat helps to release stored toxins.
Our metabolisms are not fixed and fluctuate depending on activity and other things. When you come off the fast you will need less to eat for awhile and as calorie intake increases again the metabolism should too. I wouldn't worry.
nik

Lifting weights would help I assume. Since muscles help build up your metabolism, lifting while on the clease would be good. Also, I think the cleanse will help your metablism since it cleanses the liver, and the liver is the powerhouse of your metabolism.