Ok i know this sounds weird but it helps!

The trick I read about is just use your meter, if it's a sugar soda it should read high.

can I tell just by tastting it??

honey I can tell by smelling it.. even in a fast food place with the lid on it. the smell is sooo strongly different..

I used to do this with the test strips where you wiped off the blood before there were widespread meters ... what were those called? chem strips?

I occasionally can't tell between fountain sodas, but I usually use my husband as a test case instead of a ketone strip. He hates diet, so he notices right away. (:

Wow I never thought of that! I actually had a scare at a basketball game once...my dad ordered a soda but couldnt remember if he ordered a diet or reg....and that was when I was on shots so I couldn't have corrected w/o taking another needle...so I tested my bg like 20 times in 45 minutes to make sure it wasn't going up a lot. Thanks for the tip!!

that's really cool.  i never thought about that before.  thanks.