I agree with Nancy about the best time of day to test. First thing in the morning, it's not likely to be due to exercise or what you ate, or any of those other variables.

I remember reading here in several posts that you can usually get your darkest reading at night, but if the stix are picking up sugar alcohols or ketones from exercise, well, that doesn't really tell you what's being burned fat-wise.

Morning readings for me are lightest. I like to test the second 'trip' in the morning, because I think the first piddle of the day might be fairly diluted due to the volume of fluid. Does that make sense?