Using E=mc2 1 gram contains about two thousand million (large) calories ... or do you mean food energy ...It depends on the food. Different kinds of food contain different amounts of food energy per...
In 1 gram of what? 1 gram of carbohydrate is 4 calories. 1 gram of protein is 4 calories. 1 gram of fat is 9 calories and 1 gram of alcohol is 7 calories.