Yah, it's very true. I can't remember why, but I do remember that the actress who played Elaine on Taxi (what the heck is her name?!) wrote a book on going veg, and she said that was one of the effects.
Also, to get way too personal, my family has all kinds of yucky digestive problems like diverticulitis and other things, and let's just say as a kid I spent a lot of time in the bathroom...so that's been one of the best parts about being vegetarian for me. Much less strain, shall we say! Being veggie (especially vegan) helps keep things moving along better, so you might notice more frequency in the bm dept. too. It prolly doesn't sound too appealing, but it's so much easier on your body...