I feel like it's more related to the refined sugar added to improve the shelf live in the supermarket in the 50ies that are responsible, it's something they didn't have access back in the days. It's clearly something our body is not used to and store it straight into fat. (sugar triggers the same area in the brain as cocaine, so it's clearly addicting) So it looks like it's more about food evolution that went too fast for our body to adapt in time. And that is different based on DNA too, some people get a lot fatter than other, slow/fast metabolism ...