Here's what we actually know. In the U.S., more dairy in the diet -- of whatever variety -- is generally associated with better health and weight outcomes. But that is likely because in the context of our culture, more dairy means less soda. In global context, some of the world's healthiest diets and most convincing intervention trials have de-emphasized, or even excluded dairy.
Privilege is ultimately front and center here. Mr. Cisna could have stopped his fast-food diet at any point. Many Americans, however, are beholden to unhealthy eating out of necessity. We owe it to them to help build a healthier food system, rather than hold up fast-food chains as beacons of health while simultaneously chastising individuals for making "bad choices."