[umilegenio]

I feel that these attacks on the rationality (and intelligence) of the average person are misguided. Rationality means evaluating the information provided to you. If you do not give importance to any qualitative information (e.g., taste), it makes sense to evaluate them on the quantitative information alone (i.e., lower fat) which is not relevant for many people.

I would go as far as to say that even in cases such as the gluten-free fad, people are somewhat justified. Producers started saying that their products were gluten-free to serve the customers that needed that information (i.e., celiacs). However, the average person did not know about celiac disease, so they reasonably thought that the information was for them. The logical conclusion was that gluten was bad. Now, that is wrong, but to be fair how are you supposed to know that? You are not a dietitian.

It's not a matter of rationality, but that is difficult to evaluate information if you do not understand the context in which is produced.