The LCHF diet is not only sustainable, it has changed the lives of many people I know, including people who claim
it has improved their mental states, emotional states, chronic pain, and weight gain.
I myself was pre-diabetic from the standard western diet of 2000kcal+ daily refined carbohydrates, and have pulled back from the brink by going LCHF.
Don’t dismiss it without a little bit of experience. It’s a growing movement, and it isn’t a fad. It has provided real results and real improvement to many, many people, and has spawned dozens or hundreds of successful small businesses.