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.
You would have to deny the laws of thermodynamics to assert such a thing.
Genetics of certain individuals can favor ways of dealing with to much energy input that is not fat storage (like generating more movement or heat), but thermodynamically all time system input is balanced with all time system output.
Denying thermodynamics is not wise, the empirical evidence for it is very very strong!
This does however not in anyway point to some proposition where obesity is not caused by food overconsumption. It does however showcase that genes have effects that increases the statistical likelihood for some people with certain genetics to become obese. And that the threshold for food overconsumption for an individual will depend on the individuals genes. But that is not a bold new statement, another example would be that a large human will require more energy to live, their food overconsumption threshold will be at a higher energy value.