Dr.NutriCornell said:

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.

There is a second half to this that has not been said yet. Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then measure again under the same conditions.

The figures, for anyone assembling their own picture. Practical: whatever you change, write down the date and the reason. In three months the reason is what you will have forgotten, and the reason is what makes the record worth having.

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

What would you measure differently if you were starting again?

DoseLogDan said:

Practical: whatever you change, write down the date and the reason.

Careful with the causal language. Two things moving together in a period when five things changed is not a mechanism, and stating it as one makes the thread less useful to somebody reading it later.

DoseLogDan said:

Practical: whatever you change, write down the date and the reason.

Agreed, and the size of the effect matters as much as its existence. Something real and small gets treated here as though it were real and decisive.