I still don’t get why there are caloric deficits

I’m a tad confused, all. My understanding is as follows (I’m doing OMAD): - The point of intermittent fasting is to give the body time to tap into fat reserves. Eating leads to insulin production, which disrupts that. - Reducing caloric intake does not lead to weight loss because the metabolism simply adjusts your metabolic rate. - Therefore, say your basal metabolic rate is 1880 calories per day. There is no real advantage to reducing your calories to 1500/day with fasting, unless you want that to become your new basal metabolic rate over time(?). For example, there’s that famous study of runners in a tribe who burn only 1,200 calories a day because that’s what they’re used to eating. - Of course, you do not want to exceed your basal metabolic rate and eat like 2,500 calories during your one meal a day. What am I missing here? Why are some folks doing IF *and* a caloric deficit? Cheers, thanks in advance.

Answer

I think you’re missing something here but I could have this wrong.

If you reduce your BMR over time, as a rule this is happening by losing weight/ fat and your BMR adjusting accordingly

I’ve done IF sporadically over the last few years and when I stick to it for a couple of months I’ll comfortably lose around 10lb a month if I’m also eating at a deficit

Answer

Reducing calories does produce weight loss. It sure why you think it doesn’t. IF is an effective way of reducing calories for many and healing insulin issues but if you eat your tdee even if once a day or every other day twice your tdee you won’t lose weight in any significant way. Metabolic adaptation is real but generally not an immediate or huge effect (eg if your tdee is 2500 kcal and you eat 2000 you will lose weight and your metabolism will Mostly likely adapt to your new lower weight over time but not suddenly slow down to match your consumption..takes a long period of time eating under bmr to really impact metabolism. This is also another reason why slow n steady may be better than extreme dieting. One potentially good thing about IF is it may help prevent this kind of adaptation by cycling lower and higher consumption periods.. So IF combined with caloric reduction likely produces weight loss better than either one alone …but if you still eat more than you burn it’s not a magic bullet.