Calmness and serenity are measurable physical states. Brain waves can be measured. Serotonin levels can be measured. And so forth. The benefits of meditation appear to be independent of the God Concept (if any) held as sacred by the meditator.
Mind, intent, and consciousness are no more measurable than a God Concept. Calmness, serenity, serotonin, and brainwaves can all exist without anybody "meaning" them.
And not to put too fine a point on it, but you could take all the nutrients out of a plate full of steak, potatoes, and veggies and offer them, if not in powdered form, at least as some type of brownish jelly.