IFing is only hard part of the month. Like half of it. And it's usually hard for me to put off breakfast and eat only dinner. Eating breakfast and skipping dinner is easier but I do get really hungry by the end of the night. I would go nuts doing a fast like that every day. I'm really hungry for breakfast after my 23 hour fast.
I'm back to doing my 23 hour fasts once a week. I stopped for a couple of months because I got way too cold doing it. By the end of the evening, after I rode my motorcycle home in the freezing cold night air, I would be so cold that nothing would warm me up except to stand under water so hot it left red marks on my skin. I got tired of that. I've always been cold all my entire life so it's not the diet that's for sure.
As for maybe there's some kind of limit on people our size, I have often thought that. The reason is, we are full-grown adults but we are small. We still get just as hungry but can't eat as much. We still need the nutrition but can't eat as much. We are small and can't generate or hold on to as much heat. If I eat more I'm a lot more warm. But then I gain weight and being fat makes me cold because who wants to move around when they are fat?
Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.