About eighty years ago the Germans piled up several million corpses testing the "eat less, move more" weight loss model. They discovered you can make it work with a well fed armed guard on the chow line. They also discovered that any food intake at all caused the body to adjust it's metabolic rate downwards in an attempt to survive on the lower calorie level. I'm sure with the German fetish for record keeping you can look up exactly how many calories it takes to wring the last watt of useful work out of somebody before he's so beaten down he'd rather take a bullet.
Why on earth anybody is still recommending this as a viable dieting strategy at this late date is beyond me. {Repressed sadistic tendencies perhaps?)