In a programme that was aired on early Sunday morning (19 July 2009), Bryce Wylde made the following claim:
We are often fooled into believing foods are low in fat when they're not. Who knew that 1% milk is actually about 24% fat by weight? Here to explain to us is Jane Durst Pulkys...
In spite of Mr Wylde's announcement, Mrs Pulkys does not explain this at all. We must therefore look elsewhere for an explanation.
First of all, I think that most of us didn't know this. The question is: is the claim correct? In order to verify this, we can ask some questions, and look at the product itself.
Is the source of the information credible?
Bryce Wylde, the presenter of Wylde on Health, claims to be a homoeopathic doctor. Science tells us that homoeopathy
has about the same efficacy as a placebo
. Pharmacological products and medical procedures are not normally accepted as efficacious if their proponents are unable to show an efficacy higher than the placebo effect.
In spite of this, Bryce Wylde defends homoeopathy as efficacious. Since he goes against what science shows us, this is evidence, but not necessarily proof, that he is not a reliable source of information. We must be careful not to use this fact to dismiss everything he says outright. The basis of science is to keep an open mind. However, it is a strong indication that we must look for confirmation of this claim elsewhere.
What do the milk vendors say?
A logical step is to verify the information provided by the vendor of the milk. In this, we are in luck, because there are several competing milk vendors on the market. This way, we can compare their data. Two examples:
Beatrice (Parmalat) tells us that their regular 1% milk contains 10 grammes of fat per litre.
Neilson Dairy tells us exactly the same thing. Their regular 1% milk contains 10 grammes of fat per litre.
This represents a bit of a problem, because the vendor's failure to mention the weight of the milk, makes it impossible to know the fat content by weight. Are these big business vendors trying to fool us? Not really. The mention of "servings" has come about at the request of the consumer because consumers considered that working with standards, such as "per 100 ml" or "per 100 grammes" was too far removed from their reality and too difficult to interpret. Hence, consumer demands are the direct cause of the opaque nature of the nutrition facts, not producer/vendor subterfuge.
Fortunately, it does not take a rocket scientist to estimate the weight of a litre of milk. "Estimate", because measuring it precisely is a lot harder than it may seem.
The easiest way to weigh a litre of milk is to simply buy a 1 litre carton, weigh it, empty it, and weigh it again. Subtracting the weight of the empty carton from the full one, gives us the weight of the milk.
I bought a carton of 1 litre regular 1% milk of the Beatrice brand, and weighed it. The weight is 1059 grammes. I then emptied it and weighed it again. The result was 36 grammes. Hence, an empty carton weighs 36 grammes, while a full one weighs 1059 grammes. In other words, a litre of 1% milk weighs 1023 grammes.
What is the fat content by weight of this milk? We apply the rule of three by dividing 10 grammes by 1023 and multiplying the result by 100. The result of this calculation is 0.98%. This result is in line with what one would expect, based on the fact that milk fat (915 grammes per litre) is slightly lighter than water, the main component of milk. However, it is also in flagrant contradiction with Wylde's claim. Since the fat content is based on the vendor's data, we should not exclude that this data is incorrect.
What about the 24% claim?
We can apply the same reasoning to the 24% claim. If 1% milk is 24% fat by weight, it is easy to calculate how much 1 litre of milk would weigh if this were true. Here again, we apply the rule of three: we divide the weight of the fat (10 grammes) by 24, and multiply the result by 100. The result of this calculation is 41.67 grammes.
Clearly, that is not the weight arrived at by weighing a carton of 1% milk.
Assuming that Wylde's claim is correct, we can reverse the reasoning and calculate the weight of the milk fat. The litre of milk I weighed, was 1023 grammes. According to the rule of three, 24% of this weight is equal to 1023 divided by 100 times 24 or 245.52 grammes. How much volume does this take?
Once again, we apply the rule of three. Since one litre of milk fat weighs 915 grammes, we divide 1000 ml by 915 grammes and multiply the result with 245.52 grammes. The result is 268.33 ml. How close does this bring us to 1%? Not very:
268.33 ml divided by 1000 ml and multiplied by 100, gives us a whopping 26.83%. Remember that we would expect 10 ml for 1% milk. In other words, Wylde's claim is wrong by more than 2600%. For comparison: Beatrice Table Cream is 18%, and Whipping Cream is 35%. Wylde's claim falls exactly halfway, as 18 plus 35 divided by 2 is 26.5%.
1% milk is supposed to have 10 ml of milk fat per litre. Since milk fat is somewhat lighter than water, we would expect this to be a little bit less than 10 grammes. Bryce Wylde's claim sounded outrageous, and simple calculations and verifications confirm this impression. In other words, the claim is wrong. 1% milk contains close to 1% fat by weight, not 24%.
Homeopathy: An Introduction
, National Center for Complementary and Alternative Medicine
Beatrice regular 1% milk
Dairy Chemistry and Physics
, University of Guelph