I know a few people who have lost a lot of weight on Atkins/keto. I think they are successful diets because they provide bright-line rules for people to follow, but they are also extreme and potentially dangerous. None of them could maintain those diets long-term because they developed things like kidney pain. Caloric restriction, eating a good balance of fat/carbs/protein, laying off saturated fats, sugar, and booze, will fix 95% of people's dietary problems, but for people with weight/eating issues the middle ground is often just too difficult a path to tread.