I’ve heard two different lines of thought when it comes to fasting and weight loss..
One of them states that by focusing meals in a small period of the day or sometimes one meal per day, even if you have a high calorie meal, your body cannot absorb all those calories at once so you end up “wasting” many of them, which allows you to lose weight even on a high calorie diet.
The other states that by limiting the period of the day that you can eat, you end up eating less calories overall, so you lose weight because of the calorie deficit, not the fasting itself.
Which one is more accepted? Or is there another theory?
Fasting is all about extending periods of no eating to maximize the benefits if eliminating blood glucose levels, activating fat burning mechanisms, and of course enjoying other hormonal and physiological benefits like increasing testosterone and HGH.
You can typically eat to satiation, or higher calorie meal(s) while fasting because your body will utilize (and deplete) available blood glucose levels rather than storing as fat because meals are far enough apart. Glycemic index of food will dictate level of insulin response and resulting BG level.
Tons of very educational videos on YouTube. Go check out Dr Fang. Some may call him one of the fathers of the modern fasting era.