Keto diets are not high protein, they are moderate protein, high fat, low to no carb diets which for many people work just fine long term. The problems come when people don’t adhere to the rules, track their macros, and/or start and stop following the diet, instead of making it a part of a healthy lifestyle. One also cannot expect to see any results if they lead a mostly sedentary life. There are many factors to doing it right and making it work, and supplementation with MCT oil and/or something like exogenous ketones just enhances your chance of success.