> He claims to have been following this diet for three months whilst maintaining the same weight, and only started seeing a drop in his weight after starting to fast for one day a week (standard sample size disclaimer etc etc).

Its interesting that I don't notice any discussion of caloric intake on either model -- if he was eating the same except skipping one day of food later, then you are looking at a ~14% reduction in weekly caloric intake, which, without any special effect of fasting, you'd expect to turbocharge weight loss.