It has been a year or two or three, but at one time there were some discussion/arguments about how weight is lost. The old school and establishment explanation is the energy balance model. Calories in/calories out - eat less move more. The carbohydrate insulin model is more recent and claims weight loss has a lot to do with hormones (although energy is still important). Insulin and glucagon being two of the most important. I'm not smart enough to argue one way or the other, but this guy probably is. Fifteen minutes long if a person is interested in how dietary advice (in my opinion) has had it wrong for 50 years and more recently the tide it turning. One thing he points out is the length of the study makes a difference. If the study period was short, little difference was seen between the models. But given enough time for fat adaptation and there was a clear winner in the research studies.

For those that like the technical side of things. Not for everyone.

https://www.youtube.com/watch?v=lnxo4NZ1knE&t=621s