[djehuty]

Humans haven't stopped evolving in the 8000 years since grains were cultivated. It would seem logical that changes allowing grains to form an effective part of the diet would have occurred. Take the example of milk - humans in heavy cattle dependent parts of the world (ie: most everywhere except north east asia) produce enzymes allowing its digestion into adulthood. So can we now digest grain effectively?

For comparison: a mutation in one gene giving a 1% increase in survival chance will reach 50% saturation in a population in an average of 100 generations. For humans that's 2500 years or so.

What I'm saying is that if you don't have a genetic disposition to gluten intolerance you're likely to be perfectly ok with grain.

[electromagnetic]

That was exactly what I was thinking. Lactose tolerance is a very recent biological evolution, so much so that there can be marked differences within an individual population. For instance, there's 30% more lactose intolerance in the South of France than in the North of France.

It seems to be a trend that in the Medetarranian areas where fishing is more readily available throughout the year that lactose intolerance is higher. Despite a very short geographical distance, the percentage differences are huge. Sicilians for example have ~70% intolerance, Italy on average has ~35% tolerance, while just over the border in Switzerland you're down to 10%.

The differences can also be seen within a very, very short geographical range. For instance the Basques, a Spanish population historically centred around the Pyrenees (mountains) have the lowest intolerance in the world at 0.3%, while the non-basque Spanish have 15% tolerance, literally from not living on the herding steppes.

The latest period at which Native Americans could have migrated is at 12,000 years ago. In this period of time they have acquired zero lactose tolerance. However in the same time period, the Siberian peoples who the Native Americans came from became lactose tolerant. Assuming the highest rate posted for Russians their lactose intolerance is ~60%, however this is a dubious figure considering population exchanges between the Mongolian and Siberian populations (they're a political divide on a single Eurasian Steppe, it seems highly doubtful that genes would have stopped their spread for our political niceties 2,000 years in the future). Assuming the Mongolian percentages, Siberians likely now have a lactose intolerance rate in the single digits. This compares to the non-steppe population in 'Inner Mongolia' (China) who hit at about 87% intolerance.

With the vast divide between lactose tolerance on such an incredibly short scale of time and distances, I highly doubt we wouldn't have evolved some sort of gluten tolerance, especially considering the vastly higher percentages of lactose intolerance compared to gluten intolerance.

Let's put it this way, unless you're a Spanish Basque, your greatest concern for adverse health effects in a sustainable diet is dairy. The Dutch, Swedes and Mongolians of the Steppe are the next to be concerned. Anyone else, be concerned when your doctor diagnoses you, because otherwise you're as dumb as a dog chasing its tail.

[msluyter]

No need to guess, though. You can buy a cheap blood sugar monitor and run experiments on postprandial (after eating) blood glucose levels. Some people are more carbohydrate sensitive than others, and high postprandial blood sugar is associated with diabetes and heart disease. Here's a post from Dr. William Davis -- sorta my hero -- on the subject:

http://heartscanblog.blogspot.com/2010/01/more-on-blood-suga...

Furthermore, cutting out grains is an easy experiment you can try for a month or so at little effort/cost. If you're like most people, you'll drop 10-20lbs without effort, and your hunger will markedly subside.

[xiaoma]

That's an excellent point. In fact, the rate of human evolution is hundreds, possibly even a thousand times faster than it was in paleolithic times. Less than 15,000 years ago, nobody had lactose tolerance or blue eyes as an adult. Now, lactose tolerance is the norm and blue eyes are no longer uncommon.

http://www.dailytech.com/Life+in+the+Fastlane+Human+Evolutio...

[electromagnetic]

IIRC lactose tolerance is only believed to have become endemic since about 8000 years ago, incidentally right around when agriculture hit the big time.

I wonder if the control of pasture lands necessitated the higher calorific quantity an animal provides when it is milked. Less herd land means a farmer would need to extract more calories per animal to survive. Similarly less migration also means less danger and higher populations, which again require more calories per animal to sustain.