The evolutionary discordance is incomplete, since it is based mainly on the genetic understanding of the human diet and a unique model of human ancestral diets, without taking into account the flexibility and variability of the human dietary behaviors over time.[27] Studies of a variety of populations around the world show that humans can live healthily with a wide variety of diets, and that in fact, humans have evolved to be flexible eaters.[28] Lactose tolerance is an example of how some humans have adapted to the introduction of dairy into their diet. While the introduction of grains, dairy, and legumes during the Neolithic revolution may have had some adverse effects on modern humans, if humans had not been nutritionally adaptable, these technological developments would have been dropped.[29]
This is a complete list of foods not allowed on the paleo diet. It’s a sad day when you first have to say goodbye to these foods but, once you start, it’s much easier and you find there are even better paleo substitutes for these foods. The first few weeks might be tough, but if you stick with it over time, it’ll be worth it. We promise. Here’s the ultimate list of foods not allowed on the paleo diet.
For most people the fact the Paleo diet delivers the best results is all they need. Improved blood lipids, weight loss, and reduced pain from autoimmunity is proof enough.  Many people however are not satisfied with blindly following any recommendations, be they nutrition or exercise related. Some folks like to know WHY they are doing something. Fortunately, the Paleo diet has stood not only the test of time, but also the rigors of scientific scrutiny.

Add yeast and maple syrup (to feed the yeast, see notes) to a large bowl. Heat up water to 105-110°F, and if you don't have a thermometer it should only feel lightly warm to touch. Pour water over yeast mixture, cover bowl with a kitchen towel and allow to rest for 7 minutes. The mixture should be bubbly, if it isn't start again (too cold water won't activate the yeast and too hot will kill it). 
Some randomized controlled trials have shown the Paleo diet to produce greater short-term benefits than diets based on national nutrition guidelines, including greater weight loss, reduced waist circumference, decreased blood pressure, increased insulin sensitivity, and improved cholesterol. However these studies were of short duration (6 months or less) with a small number of participants (less than 40). [4-6]