We already know American fast food is overflowing with fat and sugar. Now we can add salt to that list.

Flickr/TinyTall

You read that right: for every serving of Chicken McNugget you buy at a McDonald's in the United States, you're getting 1,500 grams of salt. If you made the same purchase in London, you'd only ingest 600 milligrams of salt (and the British serving size is slightly larger). That makes the American version of the popular chicken product two and a half times saltier than their counterparts across the Atlantic, according to a paper published today in the American Journal of Clinical Nutrition.

The study underscores what we've learned from other research: Americans are addicted to salt. We eat almost 3,500 milligrams of salt per day from the age of two onward, even though our bodies need less than 500 milligrams and the recommended intake is between 1,500 and 2,300 milligrams. We get most of that through processed foods and restaurant meals, which are almost universally saltier than their homemade counterparts. Note that a single serving of Chicken McNuggets in the states would get you to the lower bound of the recommended daily sodium intake.

The new journal article suggests that there could be one fairly easy path to sodium reduction: just make chicken nuggets like they do in England. Because it's not just McNuggets that exhibit this sodium-level variation: the study found similar discrepancies among countries in several different fast foods like Whoppers and pizzas.

The idea that Americans are addicted to salt may be more than an easy metaphor for the upward spiral in sodium intake Americans have experienced since the 1970s. In fact, both salt and cocaine have been shown to affect the same parts of the brain. Unlike cocaine addiction, however, our hankering for salty foods begins early -- in many cases, before we're even conscious about what our parents are feeding us.