While strictly true (calories being a measure of energy and valid for both heat and fuel potential), the difference is - unsurprisingly - small :)
Eating a large pizza (1200 kcal) straight from the freezer instead of heating it, gives you roughly 25 less kcal.
It's harder to chew too, so you might burn an extra 10 to 15 calories there!
So I found this website that lists specific heat capacities for various foods, and while it doesn't list "snacks", dry foods values seem to range from 0.3 to 1 cal•g^-1^•K^-1^ = 0.0003 to 0.001 Cal•g^-1^•K^-1^. Assuming no phase change (i.e., melting) and otherwise temperature-invariant heat capacity, the energy required for heating a 100 g snack from freezer temps (-18 °C) to body temp (37 °C) is 1.65 to 5.5 Cal. More realistically, we can compare to eating an ambient-temp (20 °C) snack; that difference is only 1.1 to 3.8 Cal... in either case, the difference is negligible, generally < 1% of the calorie count of the snack itself.
Well duh. If it's in the freezer that means you haven't eaten it!
yeah...not sure if it works like that
well i mean, your body loses heat to the cold food, so i guess it's technically correct?
It is technically correct. A familiar analogy is that it is difficult to light up a fire in cold as the cold wood needs more heat.
Whether it is significant or not is a different matter.