how many calories in one gram of fat/
A gram of carbohydrate contains 4 calories. A gram of protein also contains 4 calories. A gram of fat, though, contains 9 calories-more than twice the amount of the other 2. That's why 1 food with the same serving size as another may have far more calories. A high-fat food has many more calories than a food that's low in fat and higher in protein or carbohydrates.