Because I could lose weight on any diet if I cut calories enough, I didn't realize that it does matter what I eat, not just for health, but for weight loss too. I can lose at least as much weight on 2000 calories of low-carb eating, than I can on 1500 calories of high-carb. Also, I'm hungrier on 4000 calories of high-carb than on 1000 calories of low-carb. So eating low-carb makes a whole lot more sense.
I think "working" as in "resulting in weight loss" is only one very small part of the picture. Finding what you can stick to (or learn to stick to), what you enjoy (or can learn to enjoy), what you feel best and least hungry on.....
that's the real "secret." But it's not how we're taught to lose weight. The general practice is to randomly try diet plans, or to choose a plan philosophy and stick with it. "Trying out" different plans or constant experimentation is often seen as flaky at best.
I think the single best tool of weight loss is a daily journal - and not just of food and calories, but also of emotions, hunger, health symptoms... Over time patterns will emerge (though you have to look at big picture, what you did yesterday doesn't always show up on the scale today or even next week).