My hot take: calories in; calories out is not the end-all be-all of dieting and weight loss. People like to quote the first law of thermodynamics as if the human body operates in a vacuum. Truth is, not all the calories we take in get absorbed by the body. There is the basal metabolic rate, which differs for everybody and can fluctuate day-to-day, as well as the condition and makeup of the gut biome breaking down certain foods and making them more bioavailable. The ability of the stomach to break down foods, and the intestines to absorb them - so many factors determine how many nutrients one can absorb from the food they eat.

It is, therefore, not outlandish - not even anything special, really - to suggest that there is more to weight loss than calories in, calories out. We already know that hormones can have a significant impact on how much fat one is able to gain/lose on the exact same diet in patients with hyper/hypothyroidism. Perhaps IF puts one's body in a state to lose more fat compared to someone who is eating three square meals a day. Perhaps it's not purely calories.

More research is needed, and this is just my humble opinion.