And that is where we differ. But both Keto and fasting are things that many doctors prescribe and endorse...

The "science" relates to reduction in excess insulin not particularly calorie count.

Also, there is a new book out from an evolutionary biologist called "Burn" where he states that exercise will not help you lose weight. He spent ten years with hunter gatherers in Africa and measured their daily calorie burn and it was the same as people in the USA. Even though they do much much greater exercise.

He found the same with animals... measuring wild against in captivity.

He doesn't say that exercise isn't good for you generally but it won't help with weight loss.