Maybe if you could predict within 100 calories what you'll burn in a day, we'd know if eating 100 calories less than that would be effective. Between uncertainty about how many calories are in that fatty pork chop, and how many you're burning--how are we to be certain of the effects of an intervention that we can't even measure with any precision? Look at a fast food menu, you'll see like a 100 calorie range given for a lot of items. I think I'm eating around 2000 calories a day right now, cronometer claims that anyways, but I don't really know. I know it feels like enough food, because my current rule is, if I've eaten my macros for protein, I take as many shots of heavy cream as it takes to satisfy my appetite.