The correlation between starch consumption and number of AMY1 copies suggests that more AMY1 copies in high starch populations is caused by natural selection. It is a favorable phenotype for those individuals. Therefore, it is likely that having more copies of AMY1 in a high starch population increases fitness and produces healthier, fitter offspring. Geographically close populations with different eating habits possess a different number of copies of the AMY1 gene. This offers strong evidence that natural selection has acted on this gene.