Milk, yum yum. Remember the blow-up of the milk companies for adding permeate into the milk, thus watering it down? Permeate is what’s left after they make cheese, it’s green – so they bleach it before putting it into milk and call it “standardising”. It’s a way of bringing down the cost of milk production.
There are two other factors. One, pasteurisation. Heating milk to around 72 degrees C kills the microbes in it (probiotics and some potential nasties. Fair enough.) UHT (Ultra Heat Treated) milk (also known as long-life milk) superheats milk to 138 degrees C – above boiling point. Essentially changing the metabolic structure of the milk proteins and fats. Bad news – it’s not got much nutritional value.
Next step is to homogenise it. Essentially, homogenised milk is pumped (using high pressure) through a fine sieve, breaking apart the fat molecules into smaller fat molecules. It’s why we don’t have a fatty cap on milk anymore.
The problem with this is that the smaller the fat molecule, the easier it is to digest. It’s still there, but it’s pre-digested. Much easier to get into the bloodstream and bam! Next week it’s on your arse.
The second problem with smaller fat molecules is that fat (normal fat from milk) is really hard to digest and therefore makes us feel full. Ask a dairy farmer for a glass of real milk and see if you can go past one cup. Real milk, like your grandparents, remember, is very filling. Nowadays, real milk (unpasteurised and un-homogenised) is only allowed to be used for cosmetic reasons. (Australian Law – interesting that kids can buy energy drinks though.)