I suggest you the liquid breakfast AND a wholesome breakfast. I mean, milk can be considered as part of a breakfast, but we should eat the banana, too :P
Depends on how you use it, and probably also what kind it is. And you shouldn't be getting diarrhea if the food you eat for the rest of the day contains enough fibers and stuff, although that will obviously vary on how well your body takes to the liquid.
If your regular diet lacks protein, it's probably a reasonably good way of getting some extra.
well i could be good for you but one thing for sure is that it tastes AWFULL alot of the time
Mm, grainy artificial strawberry flavour... *cough, hack* Can taste okay too, though.