'Dietary calorie' is the second biggest hoax of the 20th century!
It was developed to measure the efficiency of steam boilers not how fat food makes you. The body doesn't incinerate food in a fire, it chemically processes and metabolises it and the two are only coincidentally loosely correlated. That's why if you eat charcoal such as charred bran which is high in calories, you will lose weight rather than gain it. What's more, if you intake lots of calories in one meal, the body can only metabolise a certain amount of it. Despite me claiming that calories are a myth anyway, to get a meaningful measurement you would have to measure calories in the food and calories in the excrement to get any meaningful figure. If you eat a whole box of chocolates at once, it's probably better than eating a few out of the box per day, due to the ineffectiveness of your body to metabolise all of that sugar and fat at once.