Additionally, it's quite common for those embracing a keto/atkins diet to use it as a warrant to eat copious amounts of red meat or any meat at every meal. There's substantial evidence suggesting such a diet increases risks of a number of serious cancers.
A friend of mine has been using the keto diet to try lose weight for a few years now. He burns through bulk cases of SlimJim beef sticks on a weekly basis. I am not looking forward to the future hospital visits. The last time I tried going on a hike with him he nearly collapsed on the first climb. I'm not trying to suggest keto diets are inherently bad for you, but it certainly seems more likely to be problematic than calorie restriction when viewed through the lens of how the average American is going to apply the keto concepts.
[1] https://www.nih.gov/news-events/nih-research-matters/calorie...