Why does KFC taste so much better than every other kind of food

"Higher sugar, fat and salt make you want to eat more." I had read this in scientific literature, and heard it in conversations with neuroscientists and psychologists. But here was a leading food designer, a Henry Ford of mass-produced food, revealing how his industry operates. To protect his business, he did not want to be identified, but he was remarkably candid, explaining how the food industry creates dishes to hit what he called the "three points of the compass".

Sugar, fat and salt make a food compelling. They stimulate neurons, cells that trigger the brain's reward system and release dopamine, a chemical that motivates our behaviour and makes us want to eat more. Many of us have what's called a "bliss point", at which we get the greatest pleasure from sugar, fat or salt. Combined in the right way, they make a product indulgent, high in "hedonic value".

During the past two decades, there has been an explosion in our ability to access and afford what scientists call highly "palatable" foods. By palatability, they don't just mean it tastes good: they are referring primarily to its capacity to stimulate the appetite. Restaurants sit at the epicentre of this explosion, along with an ever-expanding range of dishes that hit these three compass points. Sugar, fat and salt are either loaded into a core ingredient (such as meat, vegetables, potato or bread), layered on top of it, or both. Deep-fried tortilla chips are an example of loading – the fat is contained in the chip itself. When it is smothered in cheese, sour cream and sauce, that's layering.

It is not just that fast food chains serve food with more fat, sugar and salt, or that intensive processing virtually eliminates our need to chew before swallowing, or that snacks are now available at any time. It is the combination of all that, and more.

Take Kentucky Fried Chicken. My source called it "a premier example" of putting more fat on our plate. KFC's approach to battering its food results in "an optimised fat pick-up system". With its flour, salt, MSG, maltodextrin, sugar, corn syrup and spice, the fried coating imparts flavour that touches on all three points of the compass while giving the consumer the perception of a bargain – a big plate of food at a good price.

Initially, KFC meals were built around a whole chicken, with a pick-up surface that contained "an enormous amount of breading, crispiness and brownness on the surface. That makes the chicken look like more and gives it this wonderful oily flavour." Over time, the company began to realise there was less meat in a chicken nugget compared with a whole chicken, and a greater percentage of fried batter. But the real breakthrough was popcorn chicken. "The smaller the piece of meat, the greater the percentage of fat pick-up," said the food designer. "Now, we have lots of pieces of a cheaper part of the chicken." The product has been "optimised on every dimension", with the fat, sugar and salt combining with the perception of good value virtually to guarantee consumer appeal.

He walked me through some offerings at other popular food chains. Burger King's Whopper touched on the three points of the compass – then was altered for further effect. In its first, stripped-down form, the burger was explosively rich in fat, sugar and salt. Then the chain began adding more beef, extra cheese or a layer of bacon.

Monty Burnz wrote: »

"Hillbilly's - come for the chicken, stay for the fist fights'.