Agree on consulting a dietician.
Also agree it's very easy to go veg, though he doesn't seem to have to. In my experience, just going cold Tofurkey, heh, is best.
I don't like meat substitutes or tofu, there are TONS of great recipes and things - and plenty of things most people eat already that they don't think about as being vegetarian.
Lots of Mexican food is vegetarian, tons of Italian food, Chinese food, etc., etc. Once you start thinking that way, you begin to realize.
I prefer the Moosewood Cookbooks - there are a bunch, from the original Moosewood to the Enchanted Broccoli Forrest, etc. They're not all veggie but they have a really wide variety of dishes that are mostly vegetarian.
In general, protein isn't something to worry about - Americans eat way, way too much protein. There's protein in legumes, nuts, greens, etc., not even counting stuff like low-fat dairy.
Someone in the thread said to watch vegetables because they're all carb - I think they meant fruit. Fruits have a lot of carbohydrates (but it's a slower-acting carb and combined with fibre, so it's not like eating sugar), but most vegetables (there are a couple of exceptions) generally have very, very few carbs to almost none in plenty of vegetables.
Oh - to the 'meatless' Dis members in the thread - this vegetarian would like to say THANK YOU, sincerely, for making the distinction. The people who do not make the distinction end up making other people in the world ask 'but you eat chicken and fish, right?' 'Oh, no it's fine for vegetarians, it just has chicken stock,' etc., etc. to vegetarians. Specificity in language is helpful!