Do you have a source for this? Is this after deskimming the milk? Natural milk has about 3.3% of fat, but commercial milk usually has 3% or less (here you can buy 3%, 2%, 1.5%, 1% and 0% milk, and perhaps other values).
Unless you remove the skim, it's difficult to imagine that some parts just disappear.
> - Calories: 152 -> 146
Dubious: But it's easier to discuss proteins and carbs separately.
> - Protein: 8.14 g -> 8 g
Possible?: Some proteins may denaturalize (like the white of the egg), but they are sill there. Proteins are weird, so I can't say it's impossible.
> - Carbs: 12 g -> 11.4 g
Dubious: Unless you are overheating the milk to make caramel, this is very strange, almost impossible. Carbs are composed of smaller sugar units and with heat they may split or for new bound, but they don't disappear unless it's very hot.
> - Calcium: 28% DV -> 23% DV
Impossible: I don't expect calcium to react with the container or to evaporate, so it's impossible that it goes away. The biological availability may change, but it's difficult to measure.
> - Vitamin D: 24% DV -> 13% DV
Possible: Some vitamins are sensible to heating, and heating them changes the molecular structure to make then unusable, so this is totally possible. I don't remember about vitamin D in particular. Anyway, many commercial milk has additional vitamin A and D.
> - Vitamin B12: 18% DV -> 13% DV
Possible: Idem. Anyway, I but I never heard of milk with additional B12, and other foods are better sources of B12.
- Phosphorus: 22% DV -> 20% DV
Dubious: I don't expect potassium to evaporate. It may react with the container, but I doubt it. The biological availability may change a lot, because phosphorus is used to bind some molecules and they may split and the isolated phosphate may not be as useful.
So boiling reduces the amount of calories? And carbs, and proteins? How can that be?
In principle boiling could induce a lot of evaporation, so the milk would be more concentrated, and so it would have more calories per cup. But people don’t boil the milk so much as to materially reduce the amount of water in it.
I would guess that the heat chemically alters or breaks down (denatures might be the right term?) some of those macronutrients into molecules that can no longer provide caloric energy.
“Calories” measures the amount of energy a human can extract from the food. Interestingly, if you cook.a steak (for examples le) it can gain calories, not lose them.
That's the old, less accurate way. By that measure, fiber tends to have quite a lot of calories, as it's a carbohydrate, but that is now known to be wrong - fiber passes through our digestive systems almost completely undigested, and yields almost 0 calories.
Today, calorie counts are usually obtained by checking the protein, fat, sugar and fiber contents, and using known values for calorie/g of each. Those well-known values are ideally obtained either through human calorimetric studies, or through burning protein, fat, sugar directly.
The chemical breakdown of bonds also generates thermal energy, so the milk emits black-body radiation slightly more than input heat alone accounts for.
- Calories: 152 -> 146
- Protein: 8.14 g -> 8 g
- Carbs: 12 g -> 11.4 g
- Calcium: 28% DV -> 23% DV
- Vitamin D: 24% DV -> 13% DV
- Vitamin B12: 18% DV -> 13% DV
- Phosphorus: 22% DV -> 20% DV