I'm gonna go out on a limb here and say... that's silly. Were it true, more sleep would equal weight-loss.

The OP's stated goal was weight loss, not peak performance. If he were already at his weight goal AND plateauing in performance gains, then you might need to talk about increased rest. But to say that someone should lie down for forced attempts at sleep.... to help with weight loss...???

And to state that increased sleep is more important than proper eating?