[Question] Relationship between fasting fat utilization and daily energy expenditure.

Hey All, I'm a little ways into The Obesity Code and have listened to numerous Fung lectures, podcasts, etc. I've been 16/8 3-5 times a week and keto during the week for years but after starting the Obesity Code this question hit me today. The question surrounds these two premises by Jason: 1) Your body fuels itself with stored body fat during a fast. - If you don't eat until 4pm, your body will have been running on stored body fat all day. Paraphrasing, but Jason said something along the lines of "Instead of 500 calories of food for breakfast, you can fast, and your body will consume 500 calories of body fat". 2) Your body will lower your total daily caloric expenditure if you lower the number of calories you eat per day. * Example) If you lower your caloric intake from 2200 to 1500 kcal per day, your body will lower it's daily energy expenditure to 1500 kcal per day. I'm simplifying both of the points above, but it would seem to me that if you're fasting *and* lowering your caloric intake slightly, that your body wouldn't realize that your caloric intake was lowered to 1500 because it's been pulling x number of calories/fuel from fat stores. Please correct me if I'm wrong or add some clairifcation for me. Thanks.