Two American scientists told the people in industrial  nations that they would be much healthier if they ate more of the same kind of foods eaten by humans living more than 10,000 years ago. The scientists say that the human body has changed very little since human first appeared on the earth,but the way we live has changed greatly. Our body has not been able to deal with these changes in lifestyles and this has led to new kinds of sicknesses. These new sicknesses were not known in ancient times. So they are called "diseases of civilization ".Many cancers and diseases of the blood system,including heart attacks and strokes are examples of such diseases. Scientists noted  that early stoneage people used very little alcohol  or tobacco ,probably none. Ancient people also got a great deal of physical exercise,but a change in food is one of the main differences between life in ancient times and life today. Stoneage people hunted wild animals for their meat ,which had much less fat than farm animals. They also ate a lot of fresh wild vegetables and fruits. They did not use milk and other dairy products ,and they made very little use of grains . But today,we eat a large amount of dairy products and grain foods. We eat six times more salt than stoneage people. We eat more sugar. We eat twice as much fat but only one third as much protein and much less vitamin C.  People today probably do not want to live as people thousands of years ago did,but scientists say that we would be much healthier if we ate as those ancient people did,cutting the amount of fatty,salty and sweet foods. What is the main cause mentioned in the article why people today suffer from a lot of new sicknesses?
Ancient people did a great deal of physical exercise. Food is quite different between life today and life in ancient times. People today have more tobacco. People today have a lot of alcohol.