I think it's more racist than scientific (if ever). If eating meats makes people more intelligent then why IQ experiments in US show that East Asian generally have higher IQ scores than white as a race, for example, (the least IQ scores in these studies, as you might guess, belong to the black)? On the contrary, the anthropologist Jared Diamond claims that average tribal New Guinea man is more intelligent than the average white man due to law of survival.
A new European league of IQ scores has ranked the British in eighth place, well above the French, who were 19th. According to Richard Lynn of the University of Ulster, Britons have an average IQ of 100. The French scored 94. But it is not all good news. Top of the table were the Germans, with an IQ of 107. The British were also beaten by the Netherlands, Poland, Sweden, Italy, Austria and Switzerland.
Professor Lynn, who caused controversy last year by claiming that men were more intelligent than women by about five IQ points on average, said that populations in the colder, more challenging environments of Northern Europe had developed larger brains than those in warmer climates further south. The average brain size in Northern and Central Europe is 1,320cc and in southeast Europe it is 1,312cc. “The early human beings in northerly areas had to survive during cold winters when there were no plant foods and they were forced to hunt big game,” he said. “The main environmental influence on IQ is diet, and people in southeast Europe would have had less of the proteins, minerals and vitamins provided by meat which are essential for brain development.” "
My endnote: Btw, an IQ test conducted by the Americans during the Nuremburg trial tells that all of the Nazi accused have higher than average IQ scores, from 108 to 142 with the average of about 125.