In my examiner column last week I wrote about Mark Bittman’s decision to add small amounts of meat to his Vegan Before Six plan while training for a marathon. If you don’t follow Bittman, he is a celebrity chef who devised a plan to eat vegan meals before 6:00 p.m. and then whatever he wanted for dinner. He wanted to reduce his cholesterol and weight without entirely giving up his favorite foods.

As I’ve stated here more than once, I don’t like the health argument for vegan diet (not to mention the fact that there is no health argument whatsoever for vegan lifestyle) and Bittman’s VB6 program is a perfect illustration of why I don’t like it. His plan has been perfectly effective in achieving his health goals without actually being vegan. (He lost weight and lowered his cholesterol.) And the minute he had an excuse (a nutritionist told him he wasn’t getting enough protein) he gave the whole thing up.

From what I’ve read on his blog, Bittman has been very serious about trying to reduce his intake of animal food, but he absolutely does not get it about ethical veganism. So did his experiment with “semi-veganism” do more harm than good for vegan activism? My gut reaction is that it did. He gave added credence to the widespread belief that vegan diets are inferior and to the tiresome belief that it’s hard to get enough protein on a vegan diet. I am thinking it would have been a much better thing if Mark Bittman had never gone vegan before six.

But as always with these issues, the true impact is not perfectly clear. Did Bittman’s flexitarian approach convince more people to sample some of his great vegan recipes? People who might not seek out vegan food unless a celebrity chef with a New York Times blog tells them to? Did it cause some little shift in the way some people view vegan meals?

The truth is, we just don’t know.

My best guess is that we will move toward a vegan society through some interplay of many different efforts—including vegan activism, economic hits to the animal agricultural industry, and a positive focus on plant foods, aimed at mainstream people. I don’t know which of these factors will be most important or if all are important. My training is in the physical and social sciences and we science types can be annoyingly agnostic in our approach to the world. Until you show me hard data, my mind stays open to all the possibilities. As we set out to veganize the world, it is probably smart to keep in mind that we don’t have all the answers about the best approaches.

Because of that—and although I’m very displeased with Mark Bittman overall—I can’t quite make up my mind whether he has helped or harmed vegan efforts.