Food contains calories, which is nothing but a measure for energy. 1 calorie = 4.18400 joules if I am not mistaken. Does this mean that food contains less calories when it is colder?
Obviously I'm not suggesting that we should design weight loss programs around this fact but this would mean that it is possible to eat food which is negative in calories, no?
Calories are the energy released when food is burnt. They aren't a very accurate measure of the energy you get form eating them because they don't consider the actual biological process - just what happens if you burn them.
If you drink cold water or eat ice then your body must use energy to heat it to body temperature - so eating enough ice could be a diet!
See How much more energy does it take for a human body to heat 0C ice vs 0C water?
