This is excessively cynical. Different diets work for different people. Diet is such a complex mixture of culture, social environment, work environment, personal values, the personal values of people around you, your surrounding physical infrastructure, your own psychology and finally your biology.
The answer to “what diet” is “keep trying them until you find one that works, then stick with it.” There is an infinite number of totally functional combinations.
I can personally attest to low-carb. I lost 40 pounds in two years. It wasn't easy. No diet is. Everyone told me I'd gain it right back and gave me visceral reactions when I told them how I did it and how it's been years now since I've switched back to a sensibly balanced diet to maintain it.
I don't think people want that particular diet to work. Granted, it's got its downsides. And you can do it in a very unhealthy way. But being 40 pounds overweight was probably worse than intermittent lower-carb with healthy(er) options like chicken caesar salads, stuffed peppers made with turkey, or tuna salad on celery. It just let me eat less calories without as much hunger.
Probably more just to be able to fill in the calories. For instance, I probably ate a lot more tuna salad on celery than I would've if it were on bread.
Well yes, it is personal. As such no dietary advice is worth more than the experiments one conducts on themself, to see how one responds specifically.
If something isn't working, then sure, look to the science for potential solutions and try them out. Nothing, however is guaranteed.
If you're not getting the results you're hoping for, move on. Conversely, if it ain't broke, don't fix it, even if someone out there is telling you that you're doing it wrong.
For example I have a weakness for sugar cereal. I know it's on the bad list of sweet, ultraprocessed foods. I also know that, as a pre-workout meal, I perform great after crushing a half-box of Trix or Captain Crunch.
The answer to “what diet” is “keep trying them until you find one that works, then stick with it.” There is an infinite number of totally functional combinations.