I don't see what's the problem with putting a teaspoon of coconut sugar, sucanant or raw honey into your coffee to sweeten. There are 16 calories in a teaspoon of sugar. There are 100 calories in 2 tablespoons of heavy cream. Which do you think matters more? Your body can absorb a teaspoon of sugar without "breaking a fast" - that's just glycogen partitioning. 100 calories of heavy cream (nearly pure fat)? Guess again.
Don't put your trust in anyone on this forum, including me. You are the key to your own success.