I too am hypoglycemic. My blood sugar crashes if I am more than an hour late for a meal or don't eat protein with my breakfast. My suggestion? skip a meal instead of the day and spend meal time in prayer. A fast can be just one meal, you know. And drink ice water, that will help stave off the hunger pangs. If you are still worried, it is enough that you just pray.
SC:
You can also just give up something. I have given up all desserts and candy and sweet junk for the last week. Tommorrow, however, I will probably do a juice fast.
You could also do what Daniel did in the Bible...only veggies.