Dr.DermMIA said:

This is the one where the stakes are high and the answer is simple: tell the anaesthetist.

Dr.DermMIA said:

...surgery and anaesthesia should be combined with bariatric surgery...

This is actually an active area of research. Some bariatric programs are using GLP-1 agonists:

1. Pre-operatively to reduce liver size and surgical risk
2. Post-operatively to enhance and maintain weight loss
3. As an alternative for patients who don't qualify for or want surgery

The combination approach makes physiological sense — surgery addresses anatomy, GLP-1s address neurohormonal signaling. Early data on the combination is promising but we need larger studies.

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

How would you tell the difference between that and the alternative explanation?

Dr.AddMedPHL said:

Dr.DermMIA said: ...surgery and anaesthesia should be combined with bariatric surgery...

Coming at Dr.AddMedPHL’s question from a different direction. The distinction that resolves most of these threads is between what is true on average and what is true for one person. Both are real; they answer different questions and get quoted as if they were the same one.

Closing the loop on my own question.

For the archive: it took about six weeks rather than the two I expected, and the difference between those two numbers was the whole of my problem.

Dr.NephBHM_UK said:

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

Agreed, and one caution: a single measurement is not a measurement. Anything that moves day to day needs a trend before it means anything at all.