Muscle protein synthesis window — my results so far

The figures, for anyone assembling their own picture. If you are tracking this properly: same scanner, same time of day, same hydration, at least six months apart, and read grip strength or a lift number alongside it. Function is the outcome; the scan is the proxy.

Worth separating that from lean-mass preservation, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

Following on from Dr.EndoEP — and this may be the naive question:

Whether the RDA is the wrong reference entirely during rapid weight loss, and what the actual target should be?

DataDave said:

If you are tracking this properly: same scanner, same time of day, same hydration, at least six months apart, and read grip strength or a lift number…

Adding the part of the answer the thread has not reached. The honest range is roughly 20 to 40% of total loss as lean mass without deliberate resistance training, and roughly 10 to 20% with it plus adequate protein. Both numbers need a caveat that matters: "lean mass" on a DEXA is not muscle. It includes water, glycogen and the lean fraction of organs, and glycogen alone carries about three grams of water per gram. A large early lean drop is mostly the glycogen and water going, which is why the first scan flatters and the second is the honest one.

OP back with an update, since a thread like this is useless without one.

Reporting back — setting the target on reference weight rather than current weight turned an impossible number into a boring one.

Dr.RenalNash said:

The honest range is roughly 20 to 40% of total loss as lean mass without deliberate resistance training, and roughly 10 to 20% with it plus adequate…

True, and 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.

Ask again with the specifics and you will get a better answer than this one.