Why is there a calorie difference between raw and cooked foods?
The difference is mainly due to water loss or gain. Cooking methods like baking, grilling and roasting will cause a food to lose water compared to say steaming and boiling. In fact boiling may cause the food to gain weight as in the case of rice and pasta. When a food loses water it will become lighter in weight and more calorie dense – so the cooked food will contain more calories than the raw when comparing weight for weight. An example being a jacket potato. As the potato loses water during baking, it becomes more calorie dense – which is why when comparing weight for weight, a jacket potato contains more calories than boiled. On the other hand, if a food absorbs water, the calories will be lower compared to the same weight raw – because the food has become less calorie dense. This is true of rice and pasta. In most cases, it is probably easiest to weigh the raw food and use these figures. If you then cook the item and add any extra ingredients such as sugar or oil, you need to meas
