I am not a Clyde but do have to watch what and how I eat lest I start packing on bad weight but do not subscribe to any absolutes when it comes to diets.
I practice a low carb diet that is relatively free of processed foods, low in refined sugar, and rich in meats, cheese, dairy, fruits, and vegetables.
I know healthy vegetarians, vegans, and omnivores... key seems to be eating for your body type and eliminating all the processed crap.