Yeah, I've tried it years ago. The general idea is never to have protein and carbs at the same time.
Side note: I find it funny they call it "Food combining", because the term it was called in Germany roughly translates as "food parting".
I'm sure it works - in combination with portion control and/or calorie counting.
When I tried it, years ago, it was one of these ideas "I'll just follow this simple rule, and the weight will magically come off, although I still eat too much". Yeah, sure, especially since fat can be eaten with anything - not a good way to go for someone with no idea what size a portion of anything should be.
On the other hand, I find that a meal combining carbs and proteins tends to sit more heavily in the stomach, apparently it's easier to digest only one of those at the same time - so you'll probably feel better. Plus, it cuts out a lot of those favourite fattening dishes like pizza.
Thinking more about it, I'm probably following it in a way, because the general plan I'm adhering to (besides calorie counting, which has priority) is to have carbs but no protein or animal fats for breakfast and no "straight" carbs for dinner... but I'm doing that because it makes me feel better, nothing else.
So in summary I think it is a good way to put you on a road to eating more wholesome, healthier food, but unless you watch your portions, it's no road that will lead to weightloss on its own.