yeah, it wasn't recommended because for treating epilepsy they were using a powdered meal replacement (like soylent) and were missing some essential ingredients like phosphorus.
it's absolutely a diet that can work for anybody, it does require a fair amount of reading though.
well maybe the reason it's growing in popularity is the fact that generally accepted medical and regulatory advice has been idiotic, focused on reducing fats and replacing them with sugars and carbs which resulted in obesity and diabetic epidemic?
that fad lasted for 50 years, taking that into account it's probably too early to call keto a fad - i barely meet people who even know about it, let alone practice rigorously for any prolonged amount of time.
it's absolutely a diet that can work for anybody, it does require a fair amount of reading though.