Answer: Maple syrup is completely incompatible with keto, as it's almost pure sugar.
Maple syrup, a tasty breakfast classic, is sadly not compatible with the keto diet.
A single 1/4 cup serving of maple syrup contains an astounding 55 g of net carbs. It's enough that a single serving is enough to kick people out of ketosis, even if they have no other carbs for the day.
Fortunately, there are keto-friendly syrup substitutes. Instead of sugar, these syrups use keto-friendly sweeteners such as monk fruit, erythritol, and stevia.
When evaluating keto-friendly syrups, be mindful of their serving size. The USDA's standard serving size for maple syrup is 1/4 cup. Some brands list their serving size in terms of tablespoons or even teaspoons in an effort to make their product seem lower in carbs, so don't be fooled.
One example of a deceptive syrup is All-u-Lose. They advertise 0.6 g of net carbs per serving, but a closer examination reveals their serving size to be only 1 tsp. Putting that in terms of the standard 1/4 cup serving size, their net carb count is actually 7.4 g per serving!