Innumeracy & Clumsy Copy

I saw a nonsensical claim at the end of a MoneyWeek article published today, claiming,

Here’s another shocker of a stat for you -  courtesy of Ecclesiastical Investment. North America has 6% of the world’s population. But thanks to the fact that so many of its residents are fat, it has 34% of the world’s body mass.

You don't need charts or population figures or weight figures to figure out how ridiculous this claim is. How much does the average North American need to weigh relative to the average non-North-American such that the claim is true? Let's say X is the average weight of a non north american and Y is the average weight of a north american. Time to break out some pre-teen math skills:

.06Y = (.94X + .06Y)(.34)

Y = 8.07X

So, for it to be true that 6% of the population accounts for 34% of total mass, that 6% needs an average weight per person more than 8 times that of the average of the remaining 94%.

MoneyWeek must be just [mis-]repeating this. I googled and found the original source, in pubmed, freetext here. So here's the actual sentence --

North America has 6% of the world population but 34% of biomass due to obesity.

-- which is not the same as the one above. It's awkwardly worded, but what they mean is not 34% of the world's body mass, but 34% of biomass due to obesity. They calculated how much extra human biomass exists due to obesity then attributed 34% of this extra amount to North Americans. So an altogether different claim. What a relief.