I wonder that to and I’m thinking; depending on how much subcutaneous and visceral adipose tissue you have in ratio to muscle you have decides your metabolism speed?
Fat acts as if it were muscle tissue when you have a lot of it, when your body processes calories it may not know the differences? This determines your real metabolic speed?
What is really strange and a little known fact is that adipose fat tissue also stores glycogen but not as much as muscle tissue. So sugar/carbs (including ketones and FFA’s and possibly others?) can be stored as both a triglyceride and/or glycogen in adipose or muscle tissue, that is really odd?
So the onboard storage capacity of fuels and where they are stored and how fast they are depleted determines the speed limits of metabolism in terms of catabolic energy expenditure? …when your eating…your building something…anabolism?
It takes 8 hours to replenish glycogen stores if you are skilled enough to deplete them which would take 3 hours of rigorous exercise to deplete vs. 90 min. of endurance? That would leave you with a eating window to eat anything you want and remain in ketosis and not gain a pound AND BURN BODY FAT AT THE SAME TIME SIMULTANEOUSLY?
What is even more interesting if you could take what I’m describing here and get creative with it? (…if your replacing your glycogen storage faster than your depleting it?)
 “…What is a glycogen? Triglyceride storage in adipose tissue comprises the principal energy reserve in mammals. Additionally glucose can be stored as glycogen in the fed state, primarily in liver and skeletal muscle, for mobilization during times of energy deficit. Adipose tissue also contains glycogen stores albeit at very low levels. …” …More
 Muscle: The major fuels for muscle are glucose, fatty acids, and ketone bodies. This glycogen is readily converted into glucose 6-phosphate for use within muscle cells. Muscle, like the brain, lacks glucose 6-phosphatase, and so it does not export glucose. …More
 The Role of Skeletal Muscle Glycogen Breakdown for Regulation of Insulin Sensitivity by Exercise
 Fundamentals of glycogen metabolism for coaches and athletes
 “…Where is glycogen stored in the muscles? Muscle glycogen provides 1,400-2,000 calories or 350-500 grams of glycogen, which is enough for 90 minutes of endurance exercise. It is stored in muscle cells and used by those cells for energy. Liver glycogen provides about 400 calories or 100 grams of glycogen. …” …More
 “…What is the function of muscle glycogen? In humans, glycogen is made and stored primarily in the cells of the liver and skeletal muscle. Approximately 4 grams of glucose are present in the blood of humans at all times; in fasted individuals, blood glucose is maintained constant at this level at the expense of glycogen stores in the liver and skeletal muscle. …” …More