I was an ovolactovegetarian for several years in my twenties, in the late 1980's, but the lack of convenient food sources, social pressure, and mild athletic anemia, pushed me to adopt more meat-oriented diet. Also, being an insulin-dependent diabetic, eating low-fat, low-carbohydrate protein sources reduced my need for injections. Over time, I have returned to vegetarianism, although my reasons are grounded in self-interest and concern for the environment.
My energy consumption is relatively low, as I live in a major city and very selectively use automobiles for transportation. Lately though, I have been reminded that domesticated animals are large contributors to global warming (methane creation) and inefficient protein producers (4 to 16 pounds of grain to produce one pound of meat). Additionally, vegetarianism, and related calorie reduction, are associated with increased longevity. Both have pushed my back to vegetarianism.
Regardless of the history, vegetarianism is a better choice. The legitimate gripe seems to be against meat-eaters.