Ketogenic diet has very noticeable health benefits and where you won't easily be nutrient deficient. Veganism in contrast you hear stories regularly that over time some people develop health issues - is it because of the diet or something else underlying - we don't know, no one's studied it properly.

The growing counterpoint to veganism - a lot of which are people doing it for ideological reasons - from my observation is to counter the growing hate and intolerance against people who eat animals. Hunting and eating animals is a natural part of our evolution and to deny that is denying evolution; only psychopaths don't care about causing unnecessary suffering, everyone else would rather abolish factory farming where abuse is ripe and extreme. The carnivore diet is starting to trend, animal-only diet, and badly done research painting meat in a bad light is being debunked.

The place where there's no profit to be made, regarding rapid, healthy weight loss - which is water fasting; there's no profit motive to promote water fasting in the mainstream. Otherwise if there is profit to be made, and bad actors involved, then there will be propaganda being generated - and it will be the crowd who spread the content they produce, that content which doesn't cost a lot to produce - and is free to distribute especially when you design the results, the writing, to align with beliefs of members of a group.