If there are 9 calories in 1 gram of fat, 4 in 1 gram of carbs, and 4 in 1 gram of protein, you should theoretically be able to calculate the calories in a food item by knowing the fat/carbs/protein numbers. Why doesn't this work? For example, they're ordering from Pat & Oscar's tonight at work and I was looking at the nutrition facts for 1 breadstick. They're so fucking good, but I just can't do it. My point is, the numbers don't equal the calories: http://www.dietfacts.com/html/nutrition-facts/pat-and-oscars-breadsticks-hand-rolled-and-baked-fresh-throughout-the-day-42157.htm 240 calories 6 grams of fat 39 grams of carbs 6 grams of protein If you calculate the calories using the grams of fat/carbs/and protein, you'll come up with: 54 calories from fat 156 calories from carbs 24 calories from protein = 234 calories I realize the difference is small, but it exists nonetheless, and I noticed this on many food items. My question is: why?