I don’t know either however I (like you) intend to figure it out for my body).
In “The Obesity Code” Dr. Fung talks about an experiment done by Sam Feltham where he ate almost 6,000 calories per day (10% Carbs, 53% fats, 37% protein) and gained a total of only 2.7 pounds but lost more than an inch off his waste. The weight he added was lean mass. Based on the calorie-in concept, he should have gained 16 pounds.
Then he ate the exact same number of calories for the same amount of time but the marcos changed to a “fast food / fake food” diet consisting of 64% carbs, 22% fat and 14% protein and his weight shot up by 15.6 pounds and added 3.6 inches to his waste.
His point is that it is not simply the calories that cause weight, he points out time-and-again that simply reducing calories won’t make you lose weight and talks about someone that reduced their caloric intake to only 500 calories per day and still didn’t lose weight.
I don’t think Dr. Fung advocates reduced caloric intake at all, but rather altered diet. He says over and over again that reducing calories won’t make you lose weight. Fasting (at least how he explains it) does reduce overall caloric intake but that is not the reason you are fasting. His is a direct quote from
“THE CALORIC-REDUCTION THEORY of obesity was as useful as a half-built bridge. Studies repeatedly proved it did not lead to permanent weight loss.”
I don’t understand it all, but I have read his book twice now and keep learning more stuff from it.