It simple: eat less calories than maintence, you lose wieght, eat more, you gain weight. If you want to do that on saltines or pork rinds, it doesn't matter.Absolutely correct.
It all comes down to calories. All diets work. The problem is that many folks don't change their lifestyles or eating habits.
Once they lose the weight they go right back to their unhealthy lifestyle and eating habits.
It does NOT come down to caloric intake. That's been proven time and again. It ain't quite as simple as you'd like it to be. Read the Atkins book and you'll have your eyes opened. Or keep to your simplistic way of thinking and pretend you're right. It's up to you.