Contrary to the tenets of the Americanized version of Paleo, whole grains have done very well in the studies. This study shows why and it has to do with the positive effect they have on the gut:https://www.foundmyfitness.com/news/s/ccta74/clinical_trial_shows_whole_grains_modestly_increase_good_gut_bacteria_lower_inflammatory_gut_bacteria_improve_immune_cells
"New clinical trial shows that people that were given whole grains had a modest improvement in a good type of gut bacteria, modestly lowered inflammatory gut bacteria, and modestly increased memory T cells after 6 weeks compared to those given refined grains
. Since this study compared gut bacteria, inflammatory biomarkers, and immune cells in people given whole grains versus refined grains it is difficult to draw any conclusions about whole grains compared to no grains. However, there have been other intervention trials that have shown whole grains lowered inflammatory biomarkers possibly through their effect on the microbiome. Also, this intervention trial was only 6 weeks which may also account for the modest effect on the microbiome. Things are probably much more complicated and have a lot to do with gene polymorphisms (which affect an individualís glucose response), gut health, gluten sensitivity, and other factors. I do not think any absolute conclusions can be drawn from this study but still interesting to think about."