It's with different simple premise that you would not have access to eaten the Paleo Diet if the cavemen hadn't eaten it. That's the reason the Paleo Diet is also known as "The Cavemen Diet". It includes nuts, meats, fish, seeds and vegetables, all those things which you could find or hunt in the natural environment. So it's this diet which our great ancestors ate and used to live a proper life. As time goes on, people became more advanced, and also the agricultural revolution happened. We became farmers from hunters. We formed societies. And from on that day we have progressed to what we're today.
What we eat also shifted with the moment from Paleo to more contemporary which increased consumption of calories. There the problem happened. As based on Robb Wolf, Homo-Sapiens in old age spent many years as hunters and made their bodies adapts that way of just living over thousands of years, but as the revolution took place it shifted our diet but our genetics overlap with the past Homo-Sapiens, so the body never synced properly to eating the food what we are the right diet now. We started relying on grains like pasta, bread, corn, rice etc and nearly ceased the intake of vegetables, seasonal fruits and meat. Hence becoming fatter and subjected to diseases like diabetes and heart attacks. According to study about 33% people are thought as obese and 66% of us are overweight, which is getting worse day by day. The average Homo-Sapien in those days was big, strong, muscular, lively, athletic, adaptable as well as in very good condition. However a typical Homo-Sapien is obese, overweight, in poor condition, worried, sleep deprived, sorrowful and dying from countless preventable diseases.
So it's obvious that our modern diet (like grains) isn't healthy for us once we are not biologically created for it, which is easier to take that diet that allows us to make use of our genetic potential and makes us start living healthier. One more point grew up by Mr. Mark in the article from Daily Apple that grains cause type of weird reaction in our digestive system.
Basically, grains are made up of carbohydrates, and people carbohydrates are changed into glucose (a kind of sugar) within our system which produces energy and helps our body to function, and it is accustomed to perform many other tasks within our body. And then any glucose that is not consumed as energy is stored as fat in our body. This implies that how modern weight loss program is affecting our health and why the Paleo diet is a lot essential for us.