Peg, that's not entirely correct. There are some grains that don't have the vitamins/minerals in a form that humans can digest. You need two different types of grain which react together - you then get more nutrients from the two together than you would get from either individually.

Sooz, you *do* need meat, or rather you need the nutrients you get from it. If you want to do without meat, you need a very specialised diet to provide these nutrients (see paragraph above). Some countries have evolved these diets over centuries ("evolving" because people who ate other things tended not to live as long), so they can live without meat. But just removing meat from an existing diet is a guarantee of malnutrition-related problems - rickets was endemic during the Industrial Revolution, when poor people couldn't afford meat and didn't know what foods they needed to eat to stay healthy. Granted, we do now know how to do this though.

As for efficiency of land use, sure, grain-fed cows are a very inefficient use of land. But cows browsing permanent pasture are doing so in areas where the land couldn't easily be used for grains/vegetables. And sheep farming in hilly areas, or cow/sheep farming in scrubland areas such as commonly found in the US and Australia, are using areas which would not otherwise provide any food for humans. Also consider fishing - it's obviously not possible to sow seeds in the sea!

Graham.