I never stated that an average American diet is better for length of life. However, she has had more protein over the nearly two decades living in the states then an average Chinese person. She also has kept up a very active life. I do think there is something to be said when it comes to our diet in respects to average height, muscle mass, etc. It would make a VERY interesting research article. To wet your appetite I enclosed an article. Obviously, a quick Google search you get lots of articles. I choose this paper because in discusses at length diet in respects to genes. Hope this helps your search Rune B.
"Nature hides her secret because of her essential loftiness, but not by means of ruse." -Albert Einstein