Interesting points by Martin. Just keep in mind that DNA provides the parameters controlling a broad spectrum of traits and potential. In other words, traits governed by DNA can be turned on or off by many factors including environmental factors, which in this case would include dietary exposure and activity levels. These DNA parameters are simply traits, behaviors, or other physical manifestations that can be exhibited or not due to environmental exposure. These manifestations are simply following the DNA blueprint and are not the result of recent DNA mutations; rather, they occur at the cellular level due to whatever it is the individual is exposed to over the course of time. DNA does not have time to mutate from one generation to the next, but it does provide the blueprint for one to express or suppress traits. This expression or suppression occurs at the cellular level and is the reason for the interest in Epigenetics today. I've referenced a book by Bruce Lipton before, and it's a very good summation of this epigenetic dynamic. It relates well to the environment we expose ourselves to through diet and physical activity and explains the reasons for varied manifestations of traits related to health and metabolic response.

Biology of Belief, 10th Anniversary Edition by Bruce Lipton

Fascinating book and very relevant to our pursuit of a perfect human diet, or rather, a perfect N=1 WOE.