Do exploring dwellers require food and water?

As an experiment, I sent every capable (ie not pregnant adult) out into the wasteland to watch my food intake. Of course there was still a bit (because of said pregnant dwellers and children) but it was dramatically reduced. I later used this as a tactic on several different occasions where I was running out of food or water. I had the pregnant women manage the food/water/power production, and as it started to build back up again, I'd slow recall the less-capable (ie will die soon) dwellers back to the vault.

Edit: I should point out that this is a very dangerous thing to do, for if radroaches or raiders attack, my vault is not defensible at all. I took that chance rather than have my dwellers starve.

As near as I can tell, no. At the very least they aren't harmed if you're not producing enough. During one self-inflicted crisis where I was struggling to get production balanced, I ran out of water for an extended period. My entire populace at the vault ended up suffering around 50% radiation sickness and their happiness fell to 10%. The one vault dweller who was out exploring at the time didn't suffer any radiation sickness and her happiness remained at 75%. So it doesn't appear that they consume any food or water.