Humans did not evolve to eat bread.
This is simply reverse hysteria. Bread is not inherently unhealthy. It has to do more with our ability, or current lack thereof, to burn the carbohydrates that bread represents.
Bread became the staff of life when people had very high energy demands and little to eat to fund them. In that regard bread functions as its historic name implies. Our current lack of muscle mass and sedentary lifestyles simply preclude the quantities of bread the we consume. That is the problem. We cannot eat the quantities of bread we consume without a lot more exertion on a regular basis.