I think his goal was mostly to make a point about all the fad diets. For weight loss, the traditional approach is still the best - eat food, not too much, mostly plants. It doesn't matter if you're on the Atkins diet, the South Beach diet, or the Twinkie diet - if you reduce your calorie consumption, you'll lose weight.

It's more important to focus on portion sizes than on eliminating any particular food group. The trick is making sure you're still getting enough vitamins and minerals, regardless of what diet you're on. Even with his daily multivitamin, protein shake, and canned veggies, I'd be worried about his vitamin and mineral intake. I would wonder about the effects of his limited diet over the long term.