I'm not sure what he bases this on, I tried checking out his research on pubmed, I couldn't find much to suggest that such a slow process was better for maintenance. The idea that if you lose weight and then hold it for a month, your body weight setpoint will readjust, needs testing. He's more or less saying that the common claim that trying to lose weight too fast will put a person in "starvation mode," is backed up by science, if that were true, you'd think we'd have heard about it by now.