I occasionally joke that I know the perfect diet: my wife and I went on a hard two week hike a few years ago. We both lost 10-15 lbs and neither of us had the weight to lose at the start. I make sure people know I am joking when I recommend it though: it would be a very bad idea for most people to try it, and that probably includes me.
By the way, if anyone wants to attempt an unsupported hike of the John Muir trail, send me an email and I will be happy to give you some advice.
The first time I came to China, I didn't know how to find palatable food. (Yes, this was something I worried about beforehand.) Over the course of three months, I lost 15 pounds.
I had been variously described, before that point, as "thin", "stick-thin", and "skeletal".
When my dad picked me up at the airport afterwards, he was shocked. He said I looked like I was literally starving to death, which in a limited sense was true. I spent a lot of those three months visualizing pizza.
Was it the perfect diet? I'm sure the approach (just refuse to eat what's available) works. But it was a truly awful experience. Not recommended to anyone.
By the way, if anyone wants to attempt an unsupported hike of the John Muir trail, send me an email and I will be happy to give you some advice.