I don't really care for the notion that the human body doesn't follow the first law of thermo. At the end of the day, it does. It just depends how you are doing your accounting.
Eating ketogenic has a number of aspects to it that helps weight loss. You will probably raise your resting metabolism. You will also probably tend to eat fewer calories through the day due to the high satiety of the food. In my experience, it's a good tool, but it's not magic. There are short-comings.
It's possible to gain weight eating a ketogenic diet. There are mechanisms beyond insulin that allow fat storage. It's still possible to overrun your metabolism, but it's simply less likely.