Fruit and berries on strange planets either make you live or make you die. Therefore the point at which to start toying with them is when you're going to die if you don't. That way you stay ahead. The secret to healthy hitchhiking is to eat junk food.
- Douglas Adams, The Hitchhiker's Guide to the Galaxy

There is junk food, and then there is junk food. One person's junk food is another's nourishing snack: an Englishman, for example, may insist that Brain's Faggots are a gourmet delight, while the North Carolinian will clamour for livermush, that square delectable composed of otherwise indigestible pig parts. However, sausage can be argued to contain, at the least, some form of nutrition, just as insects may be edible though not very tasty. The essential criteria for labelling a comestible as junk food are:

• They contain unacceptable levels of Things That Are Bad for You¹, such as salt, sugar, and/or fat.
• They possess marginal nutritional value – unlike the less tasty pork offal or bugs.
• As food choices, they impart no cachet of connoisseurship on their devotees – in other words, they're not cool.

Such, alas, is the humble cheese puff, not to be confused with the gougère, which is a fancy French pastry, despite the similar name in English. Commercially produced cheese puffs – a snack food consisting of puffed corn (maize) flavoured with cheese – offer marginal nutritional value. To be honest, their nutritional value could be regarded as negative. Actual values vary from brand to brand, but overall, they are high in fat and sodium, while being low in fibre. Worse, cheese puffs are covered with cheese (or faux cheese) powder, which will annoy your mum or flatmate when, inevitably, you get it all over the furniture. But the snacks – also variously called cheese curls, cheese balls, cheesy puffs, corn curls, or even corn cheese – are tasty, crunchy, and addictive, which accounts for the fact that Utz Quality Foods of Hanover, Pennsylvania, sell their (round) cheese balls in giant 35-ounce (992 g) barrels² for the chomping satisfaction of famished computer geeks and movie-watching nerds. The unglamorous food is so habit-forming that it can form the basis for marathon eating challenges.

Outraged health experts can point to the cheese puff's lack of nutritive value as an argument against overconsumption. But if they're historically minded, they might also add, 'And besides, the monstrosities were first produced on machinery designed for animal fodder.' And this would be true.

Yes, junk food addicts, the cheese puff or cheese curl was an accidental invention of the livestock feeding industry.

The Story of Puffed Corn with Cheese

First, there was an agronomist, one Clair B Matthews by name, in the town of Beloit, Wisconsin. Wisconsin is a dairy state, please note. In order to produce so much milk and cheese, Wisconsin raises a lot of cows. Back in the 1930s, Wisconsin farmers raised a lot of other livestock, including pigs, chickens, and rabbits. Feeding all these animals was a market opportunity for Matthews and his partners Harry Adams and EE Berry at the Flakall Corporation, founded in 1932. The Flakall Corporation had a patented machine to make flaked rabbit feed. They also cooked their feed to make it more digestible to the rabbits.

One day, when machine operator Ed Wilson was cleaning the machine by feeding it cracked corn, he noticed something: the machine ran hot. So the wet, cracked corn used for cleaning came out in fluffy cooked sticks. 'Hm', he thought. 'Might be something in that'. Besides, this was during the Great Depression, and a lot of people were hungry. So Wilson took the cooked corn sticks home to his wife, who, being enterprising, salted them, deep-fried them, and – it being Wisconsin – sprinkled cheese on them. The neighbours loved them – and a new form of junk food was born.

The process was patented in 1942. With a brief delay for World War II to finish, attorney Harry Adams and his sons started their own company, the Adams Corporation, and started making Korn Kurls (TM). But they'd not only invented a new way to ruin people's diets. They'd also applied an industrial process to food that would revolutionise the postwar junk food business. It's called extrusion.

Extrude This

Extrusion is the process of pushing a doughlike material through a die or restricted space to give it a new shape. The bits of corn that resulted from this process are called 'collets'. (And now you know a new word.) The collets needed to have about 20% moisture to fry up right.

Extrusion is why you can enjoy your fried corn, wheat, or other grain in a variety of pleasing shapes and sizes, suitable for chomping, dipping, or rolling under the sofa during the movie. The growing US market in 'ethnic foods' (meaning 'not usually eaten by the Anglo Saxons, Germans, or Scots Irish') was greatly benefitted by this process. Tortilla chips? Extruded.

The Adams Corporation led the market in extruded foodstuffs in the 40s and 50s, but other companies followed. The shelves at grocery and convenience stores abound with enough enticing varieties of extruded grains, mixed with unhealthy quantities of fat, salt, sugar, cheese (or 'cheese food') and indigestion-inducing spices to keep the consumer world overweight for the foreseeable future.

It's all about unintended consequences. Pass the cheese puffs, please. But don't give any to my dog. After all, they're not intended for animal consumption.