I have a theory I'm calling the Fat Leverage Hypothesis. The mirror image of Protein Leverage, it happens when protein's more than adequate, and carbs and fat are both very low. In this context low fat to protein ratio causes increased calorie consumption driven by energy hunger.

I've seen many recent anecdotes to suggest this happens, the most recent of which is here: https://twitter.com/celticcarnivore/status/1150785289855488000?s=21