I think of a fad as being something considered extremely fashionable (and in my mind, refers primarily to short lived clothing fashions), but only for a very short period of time - a lot of people jump on it, because everyone else is doing it. But they have no real commitment to it, and if they tire of it, they'll be off of it as soon as the next big thing comes along.

The second part of the section I bolded is my main reason. I've seen a lot of people jump on the gluten free bandwagon, thinking that going gluten free will be THE answer to all their problems, whether it's weight, digestive issues, mental fog, skin problems, or a dozen other issues. They may initially see a significant improvement in any or all of those areas, because even though the only thing they're concerned about eliminating from their diet is gluten, when they're just starting it, they're not only eliminating gluten, they've also eliminated a tremendous amount of junk (which just happens to contain gluten, or is not labeled gluten free) from their diets. Not surprisingly, they decide that they've found the answer. And if they'd stick to the basics - a whole foods, non-gluten diet of meat, cheese, eggs, produce - they'd continue to do very well, because any time you get away from so much junky food, you're going to see a great improvement.

But then the ones who only tried gluten free as yet another diet craze to come down the pike (meaning it's not a lifestyle change), will soon start craving their old favorite foods.

Meanwhile, the food industry has noticed the gluten free trend, so they see the potential for lots of $$$ to be made from people craving gluten free products to replace the junk they miss eating... So now there's entire sections of the grocery store devoted to gluten free products, with lots and lots of items available which are gluten free, but just as junky (and likely to cause many of the same problems) as the gluten containing products they used to eat. Those are not remotely whole, nutritious foods - they're all chemical laden concoctions with every bit as much of a junk factor as the gluten containing foods they used to eat.

The same thing is happening with a lot of people who jumped on the keto bandwagon. They start to crave the junk they used to eat, and the food manufacturers are only too happy to make big bucks from people who are willing to eat anything that they claim will meet the criteria of the diet, no matter how junky of a chemical stew it really is.

THOSE are the types who turn a perfectly viable and valuable way of eating into a short lived craze or fad - and by calling it a fad, what I really mean is that it's a fad for the type of person who jumps on every new diet trend, because they've junked up a perfectly good diet so much that it's not long before they're in just as bad shape as they were before. WE can easily see why it's not helping - it's because they end up eating just as much junk as they ate before going gluten free (or keto), but all they see is that their diet is not working any more, so they go back to SAD, or skip to the next diet trend.

So just as LC has come and gone as a popular diet multiple times over the last few decades (due to manufactured LC junk foods), I think gluten free will also fall from favor before long too. Again, it's not because it's not important, not because it's not a viable or valuable way of eating - it's because most people who are doing it aren't paying attention to the the "basis of the object's qualities" - that in order for it to truly work, you need to stick to whole, nutritious foods. If they continue to put junk into their bodies (albeit gluten free junk), it will end up being a gluten free SAD, which will not be effective, and will inevitably lead to it falling out of fashion for the bulk of those who tried it.

That's what makes it into what I'd consider a fad, and still, I really only consider it to be "a bit of a fad", because I realize it's valuable and sustainable - but that most people doing gluten free aren't going to stick to it very long for the exact reasons mentioned above. I know it's frustrating to think about it like that, but that's what I already see happening, as so many people jump on LC/keto or gluten free, do well for a while, then start adding every manufactured food they can find that claims to fit the diet... and then they give up because it's not working any more.