For those people who understand how natural selection works:...?

Yes, natural selection is showing itself through obesity, but since the entire populace is consuming these processed foods, I think we will adapt rather than be brought to the point of disease and infertility because there will be incentive to cure and treat. Keep in mind that with every decade the lifespan of an average human is actually increasing not decreasing, and has been increasing even after we began to consume Doritos and Twinkies and Newports. This is because of modernized medicine. So natural selection has no place in our society anymore.