There are many who believe that meat is the primary food source for humans, and others who hold just as dearly to vegetables. If man were truly evolved from lower animals, he would know instinctively what to eat just as all animals do. It would not even be an issue probably. And if you say that man developed a reasoning ability by which he questions things, I would say that that reasoning ability should just as well have helped to settle the issue. The issue of whether or not man is descended from lower animals really boils down to whether he is supposed to live according to social darwinism.
Lower animals live according to the rule of survival of the fittest.
But this is not the way man is supposed to live. We are supposed to be kindhearted and helpful to those less fortunate than ourselves. Furthermore this outlook is at the heart of man rather than some late evolutionary development. Scientists who complacently point to similarities between homo sapiens and the lower animals have never seen the need to investigate this basic difference. Scientists have not sought to explain this difference in biological terms.