There were university publications on black cats being harbingers of bad luck? While it's hard to juxtapose what constituted an 'equivalent' level evidence during what are otherwise radically different historical time periods, this claim strikes me as stretching the analogy quite far.
> But fear of black cats, same as the healthy-food religion, is superstition precisely because it is a belief people accept based on lower standards of evidence than they would in other aspects of their lives
Multiple academic findings corroborating each other is typically seen as enough evidence upon which to base action. If not, then what constitutes adequate evidence?
Also, it would be helpful if you could point out aspects of peoples lives in which they generally behave according to your definition of rationality, or in which they maintain a 'high' standard of evidence.
There is little of that in nutritional research.
> Also, it would be helpful if you could point out aspects of peoples lives in which they generally behave according to your definition of rationality, or in which they maintain a 'high' standard of evidence.
I'll try, but first I'd like to point out that I don't think there's hardly any important decision people make rationally. I personally believe that people are utterly incapable of rational thought in all but the most emotionally-neutral of situations (and even when they are somehow able to think rationally, they are often unable to follow through with action), but that is a little beside the point.
People require an impossibly rigorous proof to sway their political opinions (you can call it the opposite kind of superstition. If healthy food is a new cult, politics is like an old, established religion).
Also economics and finance. Economics is also a highly debated field with about as much scientific rigor as nutritional research in its current form, and yet most people are much more careful about changing their spending habits -- or the economic policy they support, which brings us back to politics -- and certainly much less radically than their eating habits. Again, this may be superstition that causes inaction rather than action, but I think it's qualitatively different from our food superstition.
Raising children, too, I think, is different. I can't quite compare it to food (I haven't had the time to think it), but while there are many child-rearing fads, they somehow "feel" different from food fads. They feel more like fads, while healthy eating feels more like religion.
Sorry for not being very rigorous myself, but I'm just raising some things we can think about.
Perhaps I have not made my case clearly. Magical thinking has two parts: the first is being wrong (although that's not essential for magical thinking; it can be accidentally true); the second -- and this is what distinguishes magical thinking and superstition from mere false belief -- is its motivation to action. People believe many things that are wrong, but superstition is the false belief that changes their behavior.
My claim is that healthy food falls under the category of superstition, or magical thinking, because people so readily turn what you call limited information into action. What we may think of as "classical superstition", say fear of black cats, was also based on limited information. I'm sure there was plenty of evidence to suggest black cats are harbingers of bad luck. So, fearing black cats could be classified as rational action.
But fear of black cats, same as the healthy-food religion, is superstition precisely because it is a belief people accept based on lower standards of evidence than they would in other aspects of their lives, and at the same time motivates them to take action. Why? Because they want to believe it. It makes them either afraid or hopeful.