This is the version of the explanation I wish somebody had given me, written down before I forget what confused me. It is about protein intake, and it is deliberately narrow — everything I am not confident about is marked as such.
What is actually established
Distribution matters less than total but it is not nothing. Roughly 25 to 40g per sitting with enough leucine to trigger synthesis, three or four times a day, is more effective than the same total in one enormous evening meal — and on a suppressed appetite the enormous evening meal is the one you will not finish anyway.
The condition it depends on
Anyone with reduced kidney function needs that target set by a clinician rather than a forum. High protein is safe in normal kidneys and is not automatically safe in impaired ones.
The practical version
The arithmetic that makes it tractable: reference weight in kg times 1.6 gives the target; divide by four for a per-sitting figure; then find four foods that hit that figure in a volume you can actually finish. Most people need two of the four to be liquid or semi-liquid early on.
What I am not sure about
What I am after is whether the RDA is the wrong reference entirely during rapid weight loss, and what the actual target should be. I have searched first, so if this is covered somewhere point me at it and I will read it.
— labquiet_amy · corrections welcome and will be edited into this post with credit