Lately, a little problem had been bugging me. If I had a cup of granular and a cup of powdered, with would have more calories and all that? I’ve been thinking that it would be the powdered, as you would fit more in the cup. But, I’m not sure.
I also have no clue as to why I began wondering this, either. But now that I am, I need an answer.
Weigh them both, whichever weighs more has more calories. I’d guess they’re pretty much the same unless grinding the sugar creates grains with very different shapes.
My copy of *The Joy of Cooking * says that you can substitute 1 3/4 cup confectioner’s sugar for one cup granulated sugar. So, one cup of confectioner’s sugar would have fewer calories than one cup of granulated sugar. If you go by weight, they would be equal. (I am ignoring the 3% of cornstarch in the confectioner’s sugar.)
1 cup (approximately 115 grams) of powdered sugar contains an average of 480 calories. One cup of granulated sugar (approximately 200 grams), 770 calories. I say “approximately” and “on average” because confectioner’s sugar, like flour (but unlike granulated sugar) can vary a bit on how much fits into a cup, based on packing, humidity and technique.
Confectioner’s sugar, in addition to sugar, has additives like corn starch to keep it dry and fluffy, and lots and lots of air in it, so it has far less actual sugar and therefore calories in the same approximate volume. Gram for gram, they’re so close as to make no difference: 4 calories per gram, just like any carbohydrate.