If I recall correctly, breeding corn is often working with additive variances. I notice that you are knowledgable about metabolic processes, so I guess the relevant questions here are what metabolic characters are vulnerable to selection and at what point do you begin to see gross changes?



I think if we look at the overall history of human evolution (and just when did that precisely begin?) we'll see this same story repeated over and over. The Pima Indians probably aren't susceptible to carbs the way they are by chance alone - their lifestyle and diet selected for those characteristics. In other words, their tendency to IR and obesity today is what helped them to survive and thrive in the conditions of yesteryear. And I do agree with Nancy that the intense physical demands on generations of our ancestors, which suddenly no longer exist for many of us, play a large role in the health problems we develop nowadays.


This is ice cold evolutionary biology here, not the spiritual stuff about how we are all wonderful inside. I believe we are biologically hardwired to respond to people who appear healthy, have good waist-hip ratios (in women, a sign of reproductive health), symmetry, cranio-facial neoteny (fascinating stuff), and we do not respond as well to people who appear unhealthy in some way, or have signs of developmental abnormality. Dawkin's "The Selfish Gene" comes to mind as a good book that deals with this stuff. So that's why I predict reduced evolutionary fitness for people who become unhealthy from diet (or whatever), even if they are perfectly capable of reproduction. There will be more of those folk who want to but don't then among people who radiate health, if you know what I mean. And if their kids inherit the same health problems they will face the same fitness challenges as their parents did. So, due to "heterozygote sheltering" those genes will always be with us, but their proportions will simply change within the population.