Peter Jackson's 'Skull Island Diet'

Photo: ZUMA Press/Warner Bros.

Peter Jackson continues to surprise people with his new svelte appearance.

The 49-year-old filmmaker appeared in a series of promotion photos yesterday for "The Hobbit" — looking visibly thinner and more fit than when he last showed us Middle Earth.

In reality, Jackson has been living a healthier lifestyle ever since he undertook a grueling 10-month production shoot for the 2005 blockbuster "King Kong." “I just got tired of being overweight and unfit, so I changed my diet from hamburgers to yogurt and muesli and it seems to work," he told the UK Telegraph.

As a result of that simple change, Jackson says he lost more than 70 pounds in what's been dubbed the "Skull Island Diet" after the fictional home of the great ape King Kong.

According to one doctor, Jackson's results were typical for that type of lifestyle change. "It's not unrealistic to achieve that — if you were following the ... standard healthy eating guidelines, reduced fat, plenty of unrefined carbohydrates, fruits and vegetables, lean sources of protein," said Dr. Toni Steer of the Medical Research Council's human nutrition unit in Cambridge.

Jackson insists that he did not exercise to lose the weight — but for those looking for even better results, a little physical activity would probably do the trick. The fact that the director has kept the pounds off over the last five years also goes to show how important a healthy diet is to maintaining weight loss.

So there you have it — the not-so-secret "Skull Island" diet that can give you great results with some simple modifications to your food choices. If this whole "Hobbit" thing goes belly up, at least Jackson will have a killer name for a healthy living cookbook.