It's easy to blame a lot of stuff on genetics. It takes many many many generations for human gene mutation to occur. It's the epigenetic (environmental) influences that enable people to express or repress a gene's characteristics. These influences are "remembered" or copied at the cellular level, so they can be inherited by succeeding generations. Introducing the wrong foods over a period of time makes genes behave badly. Our recent science experiment of the Food Pyramid (MyPlate) and following a Low Fat diet are proving this to be the case. It doesn't take long (about 30 years) for a toxic environment to result in poor health outcomes.