the whole point of the maple syrup, besides calories, is the nutrition provided by it. maple syrup has many vitamins and minerals. something that is "maple flavored" will not have this. you may get dizzy or weak (more than necessary), or you may become depleted of minerals.
then again, you could be just fine with it. people do Water Fasts all the time. you could even cut out the maple part all together. even so, the stevia might be something to check out. whatever you decide to do, good luck!