If you believe the claims, the pills allow 90% of the nutrients to be absorbed, as opposed to "normal" food at 25--35%. So, the pills caloric value ends up being about the bare minimum needed...if you believe the claims.
_________________________
Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein