Our government subsidizes monocropping leaving the land barren of anything good that was ever present in the soil. Year after year the same crop on the same degraded land, depending on inputs from big agriculture to grow crops devoid of nutrition but brimming in agrichemicals needed to stave off pests and disease. This leads to folks gorging on foods that do not nourish the body and in fact, poisons it. They eat more and more and more, thinking they are still hungry and they are. In fact, they are starving for the nutrition that their bodies need. In comes the obesity in addition to many other maladies brought about by malnutrition. Those folks then head to the medical professionals...woohooo, where they are plied with lovely multicolored pills from big pharma, but only after going through the big insurance extortionists. Cradle to grave, from infant formula to pureed food for the elderly, being poisoned all the way.
Have you ever seen wealthy people who are obese? Not too many, and their kids don't generally have childhood obesity problems. I'm guessing that they can afford good food, real food, nutritious food that leaves them sated after eating a meal.
Best to grow as much of your own food as possible and buying straight from farms who grow more than one damn thing.
At least that's how I think this obesity epidemic started, but now, after many years it is the only way some people know how to eat and that's sad.