I wonder at why you ascribe a gender to what needs not gender nor has gender. 'He' was a figure of speech, even if it was a little sexist.

The simple fact of the incomplete amino acid combination in most plant species is a sign of that. In our plentiful 20th-century diet, we can gorge on many types of vegetables, therefore counterbalancing that factor, but the spread of kwashiorkor in Africa should tell you what happens to people when they're vegetarians and they can only get one type of food(granted, the Africans aren't vegetarians, but they can't really get meat, can they?). There is also the scriptural condonation of meat, but I don't think you're the kind of person who believes in a scripture. Also, prehistoric precedence; name any prehistoric or early historic clan/tribe/gathering/et al. that abstained from meat.

I exist! I am a pedant! I have a foreboding signature!