For that to be true, you'd need to explain why obesity has skyrocketed over the last few decades. It's only been a generation or two at most, so it's not genetic.
When one eats traditionally prepared (European, at least) food, it is much harder to become very fat, even if you are eating “unhealthy” foods with a lot of fat in them.
We really need regulation forcing processed foods to pass some kind of satiation-per-calorie test. It’s mind blowing that this isn’t a top level political issue.