Normally I don't sweeten my tea or coffee at all, but sometimes I use an actual level teaspoon of the real thing...
for cooking or for sweetening tart desserts like raspberries or blueberries in Greek yoghurt or strawberries in double cream, I use Splenda or other generic sucralose sweeteners.
To much caffeine can raise blood sugars, but 4/5 cups a day shouldn't do it.
What I have noticed is that sugar free carbonated cola drinks do make my BGs rise a bit, I don't know why, maybe it is something to do with the caffeine or the CO2 gas? I don't know, anyway I don't drink them now.
Personally, I stay away from chemical sweeteners; and from personal experience, I recommend you stay well away from anything containing sorbitol unless you have quick and easy access to a loo :lol: