It's the influence of his wife. He's been a vegetarian for 10 years, but his original idea of being a vegetarian was something I can really identify with. (I was a vegetarian for about 5 years a while back.) He thought: root beer and potato chips.
Yes, you know there are so many things you can eat and still be vegetarian. Most of the great snacks: ice cream, chips, candy, cookies. And all the great drinks: soda, fruit juice, beer, wine. It's only healthy if you make it healthy, which you may be less inclined to do if you're being gnawed at by that deep innate hunger for meat.
But if you can get a highly motivated, food-smart spouse to take care of you and control what food and drink arrives at your table, vegetarianism might work well. And you'll just have to take her/his word for it that sauerkraut is important or whatever crazy food theory she/he believes is true.