Would you pick a different time of day to take a regular measurement?

I like morning for habitual reasons. It's fairly straight forward to attach a BGL habit to your morning tooth brushing habit.

But if you ate the same breakfast every day and could take the measurement 30 or 60 minutes after then I could imagine that being a viable feedback loop for many people.

The problem though is practicality which is really a key part of a behavioral approach.

BTW, my data on popular diets is that there's only a 12% success rate at the 30 day mark and that the vast majority of that failure is simply failure to adhere.

But failure to adhere is not only or even often a failure of willpower. It's most often a failure of results. Why keep going if it's obviously not working?

I'm not sure the general public would agree with me, but I would be completely happy with a 12% success rate here and the main causes of failure being things like the dawn effect. It's a win if the 12% for this diet doesn't completely overlap with the 12% for other diets.