In a word: "Absolutely."
In more words: "They are probably healthier."
In her complete words.
As I said to my mother this weekend, no diet is perfect. Because humans are not perfect. And the world is imperfect. But certain diets are certainly more optimal than others. Very few sane people will reason that fruits and vegetables are bad for you. Eating them in abundance and in conjunction with whole grains, nuts, seeds, and some fun stuff every once in a while is, of course, healthful.
You can't go wrong eating lots of fresh, whole foods and minimizing the amount of food that comes in wrapping you have to open before you can eat it...you know, unless it's a banana or something.
Usually when people question the health of a plant-based diet, they are not concerned about health at all. They are concerned with tripping you up. Just like the person who questioned Brian's veganism and my vegetarianism even though they were on, I later found out, two cholesterol and blood pressure medication. In their thirties. And they hunted innocent animals too. 'Nuff said.