In some curing circles sugar is not included in the base formulations, either a wet curing brine or a dry cure simply because it is not needed to cure meat. Salt and cure are the required ingredients. Sugar is used to knock the harshness off of the salt, and to add surface color and when used in large amounts (or something like maple sugar, or maple syrup is used) will give the cooked product a sweet back-flavor.
A non-sugar dry cure recipe for bacon would be:
1.5% salt*
0.25% Cure #1
The percentages are based on the weight of the pork belly. For example, you use 15 grams of salt for each kilogram of meat, and 2.5 grams of Cure #1 for each kilogram of meat. The minimum curing time will run about a week, but for many 14 days is a magic number.
* the salt percentage is a variable, a range of 1% to 3% could be used. Do not change the percentage of Cure #1.