MikeFit_NJ said:

The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either.

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. This treats a plausible mechanism as a demonstrated one. Plausible is where you start looking, not where you stop.

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

Adding the numbers, since they settle part of this. Keep the original post as written when you update it, and add the correction underneath. An edited-away mistake is invisible to the next person who makes it.

TirzTom said:

This treats a plausible mechanism as a demonstrated one.

Coming at TirzTom’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.

One thing that is still open after DoseLogDan’s answer:

What did you change at the same time, and can you separate the two now?

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

Reporting back with a partial result, because a partial result is still better than silence. Two of the three things suggested helped; I cannot separate them and I am not going to pretend otherwise.