I read scientific reports on dairy tolerance. The intolerance starts between the ages of 4-6 years old depending on ethnicity (asians at 4, caucasians at 6). After that point, 90% of the world's population has an intolerance to it, but the tolerant amount varies per person. They believe that there was a 100% intolerance to it a century ago, but society is starting to build a tolerance for it because of the amount of consumption. Caucasian Americans were 78% intolerant, whereas Native Americas were 99% intolerant. I found it interesting. My wife stopped dairy because of how bad she felt, and she's much better now. I have not tried to quit dairy, but maybe I'll give it a go.
In
Michael Rose's talk (about his Methuselah flies and what they mean for us) at the recent ImmInst conference in Brussels, he talked about the three diet regimes that humans have lived under: Hunter Gatherer (2.5M years(?), more gatherer at first, later more hunter); Agricultural (10K years), and Industrial (100 years). He said that humans adapt to new environments in 30-60 generations. 10,000 years is ~500 generations, which should be plenty of time for deleterious genes to be flushed out if they occur much prior to the end of reproduction, (35 years for women, older for men? Maybe an average of 40?) We clearly haven't had time to adapt to the modern 'industrial' diet. It would appear that during the agricultural period, a lot of humans didn't really drink all that much milk, and tended to stop when young. That would at least fit the milk intolerance that's been described here into an evolutionary paradigm. At least some populations have been drinking milk longer, which would explain why some people tolerate it, but check this out-
Rose made a very interesting point about the relationship between evolutionary pressure and diet. As you move from the start of your reproductive period to the end, the evolutionary pressure against possession of a deleterious gene decreases, when averaged over a population. In fact, because humans aid in raising their children and grandchildren, the pressure to drop deleterious genes actually continues (at a much lower level) somewhat beyond the end of reproduction. The upshot of this is that
as you get older, it becomes more important to switch to a paleo diet. Evolution has provided most of us with very good early life adaptations to an agricultural diet, but some of these adaptations begin to fail us later in life, while our ancestral adaptations to a paleo lifestyle, due to the much longer time we had to develop them, are still active in later life. Rose's prescription for attaining a 'natural' version of the 'biological immortality' of his Methuselah flies is to switch to paleo after 40. (Earlier if not Eurasian.) You can certainly start paleo sooner, but it's not as necessary.
If you're in your 20's, you can get away with most anything; certainly an agricultural diet for all but a few of us, and some of us can eat an industrial diet without apparent harm. As you slide through your 30's, you will see things unraveling, as you get fat and your metabolism goes to hell. This described me pretty accurately. As I moved toward a paleo-ish diet over the last few years, the effects were remarkable. My version of paleo, that makes it "-ish", is that I've dropped milk but not cheese, and only cut back on grains, but haven't eliminated them. It seems to be working great at the moment. The question that's on my mind is "will I ultimately have to drop dairy and grains
entirely?" I hope not. I suppose the best way to tell would be to try an elimination diet, although that might not tip me off about subtle health differences.
