One of the more interesting pieces of folklore about cows milk is that skim milk is more fattening than regular, full-fat milk.
I've heard two different versions of this. The first doesn't try to explain how it is possible for milk minus the fat to be more fattening than milk including fat at all. There is no reason, skim milk "just is" more fattening. The so-called proof, to use the term laughingly, is that "farmers feed skim milk to pigs to fatten them". More likely they feed skim milk to pigs because (1) it is rich in vitamins and protein, and (2) it is cheap.
The second version seems a little more plausible. Skim milk is more fattening because it has added sugar to make it more palatable.
But is it true? To find out, I recorded the energy values, amounts of fat and sugar from four different brands of milk: Pauls full-fat milk, Woolworths "Lite" milk, Rev, and Farmdale UHT skim milk.
|Type||Energy/100mL (kJ)||Total : Saturated fat (g)||Sugars (g)|
|Full fat||271||3.6 : 2.3||4.8||"Lite"||193||1.4 : 0.9||5|
|Rev||191||1.3 : 0.8||4.9|
|Skim||150||0.1 : <0.1||5.3|
As the above table shows, it simply isn't true that full-fat milk is more fattening than skim milk. Skim milk has just 55 percent of the calories of full-fat milk. It is true that it has a tad more sugars (10 percent more), but that is well and truly made up for by the drop in fat content.
(It isn't necessarily the case that the extra sugar has been added to the skim milk. It may be that the process of making skim milk has a side-effect of concentrating the milk sugars. Either way, the extra calories from the milk sugars are dwarfed by the calories removed by discarding the fat.)
Now, I suppose it is just barely possible that all the milk sellers are lying when they list the nutritional analysis of their products. A grand conspiracy of thousands of dairy farmers and milk boards and scientists, all over the world, just so they can fool people into thinking that taking the fat out of milk makes it more fattening.
Nah, I don't think so.
Where does folklore like this come from? As you can see, there is a tiny, almost microscopic kernel of, not truth but plausibility to the story. Skim milk has a smidgen more sugar than regular milk. Has the myth come about from mere confusion over this factoid? I don't think so.
Even now, long after skim milk has become respectable, it still has the tiniest little shadow of weenie, hippy-dippy effeminacy. Real Men don't drink "double-decaff skinny vanilla latte with a sprinkle of cinnamon". I don't think it is a coincidence I've only heard this myth from men, none of whom are the slightest bit concerned about counting calories. Nevertheless, they justify their unwillingness to drink skim milk or low-fat milk on the grounds that fat-free milk is more fattening.
This is conjecture, of course -- who knows why people believe the things they believe? -- but I strongly suspect that the myth allows them to justify an unconscious feeling that "only girls drink skim" as being health-consciousness (thank you Herr Doktor Freud). Or perhaps they just prefer the taste of regular milk, but feel that "fat" milk is too sinful, unless it is actually better for you. Or maybe they simply like the idea of being one of the Chosen Few who are smart enough to see through all the wicked advertising that fools everybody else.
If I knew why people believed things, I could put memetics on a solid scientific grounding.