Well then, you of all people should know that calories are a measure of energy.
Yes but not a measure of the energy available biochemically.
And you of all people should know that it takes more calories in to get calories out, as some will be lost in the conversion process as heat etc.
I don't think I ever suggested that conservation of energy was bogus but whatever.
If you eat sugar to make sugar then you run at a very slight loss to overheads, but if you make it from stored pregnancy fat then you get it almost for free. The point tiktok has been making is that you get more calories out from calories in by making BM than any other activity. Exercise is for instance total crap. So if you overeat by 500 calories you will lay down maybe 300 calories worth of fat. What you can get back for that might be like 200 calories of exercise but might be 250 calories worth of sugar in milk etc. So from one point of view you can say that making BM instead of exercising gets you an extra 50 calories back.
And therefore you cannot get 500 calories out into a baby every day without taking in or having stored more than 500 calories in.
Again it would be nice to use up your fat stores for the purpose intended but if you are determined to eat extra then yes it will take some arbitrary amount more calories in to get 500 calories out to baby. This will be more than compensated for by the difference in the babies ability to extract energy from BM over FM. Or in other words we are more than likely comparing
550 calories into mum-> 500 into baby --> baby gets 400 calories to use
with
600 into baby ----> baby gets 400 calories to use.
NB. numbers made up but correct in trend.
And that those calories have to be paid for (Hm - actually, maybe the "must be paid for" bit isn't so apparent at Oxbridge)
Except for the ones you already ate which are there if you BF or not as fat and for the rest...well a factor of 15 in cost speaks for itself.
Admit it! It is WAY cheaper to BF from a calorie point of view....go on...it wont hurt and you will feel better for it.
ps. you def have to pay for calories in Oxbridge...in fact they are much cheaper almost everywhere else except london...