GOLDEN VALLEY, Minn. - Before you run out for some fast food this week, here's something to consider.

U.S and Irish researchers have put a number on just how much fatter it makes us.

When looking at the statistics from 25 high-income countries over a decade, they found every time someone buys fast food, it bumps up the average body mass index by point-zero-three points.

The researchers reported in the Bulletin of the World Health Organization that as fast food transactions have increased so has the average BMI.

Read more from NBC News.