Dr.BariatricHTX said:

The distinction that resolves most of these threads is between what is true on average and what is true for one person.

That reframing is the part I needed.

Clinical perspective, offered as context rather than as advice. There is a difference between no evidence and evidence of no effect, and this subject is one where the two get swapped freely in both directions.

Dr.ObesityMed said:

The version of this that has an answer is narrower than the version being asked.

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. Pushing back on the anecdote-stacking. Twenty people reporting the same thing is twenty samples from the same self-selected pool, not twenty independent confirmations.

The figures, for anyone assembling their own picture. For anyone reading later: the numbers in this thread are worth checking against a primary source before you act on them, including mine. Half the figures circulating in this community trace back to a secondary summary that dropped a qualifier.

That is the short version; the long version is somebody else's post.

Moderator note: the sourcing question belongs in the vendor section and has been split out. Tagging this one for the weekly digest.