interesting question

it would seem like it might work fine; my only concern is how much work your body has to do to digest the pulp. probably not that much to make a difference, but one of the goals of the Master-Cleanse is to give your digestive system a rest, and if it has to work to digest the pulp from the lemon - well, it's just not resting.

But you stilll would be cleansing and detoxing, so that alone is big benefit.