The last paragraph is very wrong, or I don't remember high school biology. So please correct me if I'm wrong.

Humans aren't evolving in response to their environment: they change the environment to suit them.

And anyway, selection doesn't really work in a few generation, and definitely not if what you are trying to select out doesn't change how many kids you might have.

By the time you die from heart disease, you've probably had all the kids you were going to.