> Because the body can only extract so much energy per minute from all of the fat in your body.

Was curious about this, went hunting for some rough data, this [0] suggests every kilogram of fat held can be drawn down at ~70 food-calories per day.

So someone with 25% body fat weighting 100kg (~220lb) could draw 1750 food calories per day, which strikes me as pretty ample unless they're also adding a bunch of physical activity.

[0] https://pubmed.ncbi.nlm.nih.gov/15615615/