You may not notice the difference next time you buy a one-kilogram bag of potatoes, but it seems that in an age of obesity the kilogram, too, has put on a bit of flab.

Scientists at Newcastle University have claimed that the original kilogram — known as the International Prototype Kilogram or the IPK — against which all other measurements of mass are set, is now likely to be “tens of micrograms heavier” than when the first standard was established in 1875. But there’s help at hand: a suntan can be used to help it lose the extra weight.

So, how will a heavier kg affect us?

According to research by Professor Peter Cumpson and Dr. Naoko Sano, a bit of extra weight would not have mattered if everyone around the world had been working to the same exact standard.

But they don’t, with each country having a slightly different definition of the kilogram.

Besides, mass is “such a fundamental unit,” they point out, that even a small change could have a “significant impact” globally, including on commodity trade. “There are cases of international trade in high-value materials — or waste — where every last microgram must be accounted for,” the scientists write in a paper published in the journal Metrologia.

“Around the world, the IPK and its 40 replicas are all growing at different rates, diverging from the original. We’re only talking about a very small change — less than 100 micrograms — so, unfortunately, we can’t all take a couple of kilograms off our weight and pretend the Christmas over-indulgence never happened. But mass is such a fundamental unit that even this very small change is significant, and the impact of a slight variation on a global scale is absolutely huge.”

Got it?

More In: International | News