I once had two yummy cranberry bars (the peanut and cranberry bars have high fibre content than the others) in one day about 9 hours apart, I wouldn't recommend it unless you have the following day free to sit on the toilet, 15 hours later with only slight warning (5 mins of rumbling) the volcano errupted, trying to get a toddler into the house (luckly I got home from shopping just in time!) and up the stairs was just to much. Needless to say the washing machine was put into action and the bathroom floor needed to be mopped & disenfected...never again!!!
Shakes can be made hot, choc mint is fab, use a large (2 litre ) jug and a hand blender to get rid of lumps. You could always make a hot vanilla shake and add coffee as a milky coffee replacement/or split it and use throughout the day to give you more coffee's
Helenx