This is certainly not true for me. Fasting 16 hours a day has changed my life. I eat relatively healthy but been eating a lot of sugar, full pizzas etc so I doubt I’m at a calorie deficit more than once a week.

As an aside, I had cancer and worked with surgeons professionally. And I am exceptionally skeptical and disappointed in the curiosity of doctors and surgeons. Some of my doctors would repeat word for word answers. My oncologist didn’t know basic questions.