> Keto, Adkins, etc...They work. But they're not diets.
Its "Atkins". And they absolutely are diets.
> It's a healthy lifestyle choice.
The aspect of lifestyle that concerns what foods you consume is called "diet". Keto, Atkins, etc. are lifestyle choices, and the specific kind of lifestyle choices they are is diets.
> Two years ago I was 70kg. Now I'm 59 ~ 61kg on average, I have more muscle mass, more energy and I feel great.
Two years ago I was 150kg. Now I'm 127kg on average. I have a lot more muscle mass, more energy, and I feel great. And I haven't taken a radically low-carb diet (and, in fact, the biggest change I made was exercise -- I stabilized my weight before that with a diet change that I've sustained, but not a radically low-carb one, though I've tried radically low-carb diets in the past, with no success [though not as much adverse health impact as my wife had when she tried them].)
Most people wanting to lose (or stop gaining) weight in the US could probably use cutting their intake across the board, and simultaneously cutting the share of that made up by carbs. Radically carb-cutting is useful for lots of people, but not everyone.
Most people could also use more exercise (again, any particular radical program may be useful for some people, but not everyone.)