We know, we just know that junk food is, let put it gently: not good for you health-wise.


We are aware that fast food eating habit and its’ nutrition is related to heart problems, high blood pressure, diabetes, osteoporosis, … you name it, girl (even depression according to a study from 2012).


But if it’s so bad for us, why, the hell, do we keep consuming it over and over again?


Well, there is an answer to it, actually.


And the science behind it gives the proper explanation.


When we eat tasty food, two factors make the experience so, so, so pleasurable.
First, there is the sensation of eating the food.


Well, what sensation really includes in its captain obvious meaning is what food tastes like (salty, sweet, that one between the all of the tastes called umami, etc) what it smells like, and how it feels in your mouth.


This last quality is known as “orosensation”. This is important.
Food companies will spend millions of dollars to discover the most satisfying level of crunch in a potato chip.


Their scientists will test for the perfect amount of fizzle in a soda.
These factors all combine to create the sensation that your brain associates with a particular food or drink.
Let’s skip to the second factor.

The actual macronutrient makeup of the food (the blend of proteins, fats, and carbohydrates that it contains).


In the case of fast/junk food, food manufacturers are looking for that utmost perfect combination of salt, sugar, and fat that gives tickles of pleasure to your cute little brain hemispheres and neurotransmitters in ultra excitement session that makes you (and your brain) keep coming back for more.


Here’s how they do it…


Dynamic contrast.

Dynamic contrast refers to a combination of different sensations in the same food. We love crunchy stuff with soft, melting stuffing? Mhm.


That is a perfect, almost elementary example of a food with dynamic contrast. The one that has an edible shell that goes super crunch-crunch followed by something soft or creamy and full of taste-active compounds.
This rule applies to a variety of our favorite food structures — the caramelized top of a creme brulee, a slice of pizza, an Oreo, or a Raffaello praline — the brain finds crunching through it very thrilling.
Salivary response. Salivation is part of the experience of eating food and the more than a food causes you to salivate, the more it will swim throughout your mouth and cover your taste buds.
Take butter, chocolate, ketchup, salad dressings, ice cream, and mayonnaise — you get the idea.

These give you a salivary response that helps cover your taste buds up with om nom nom goodness.

Science knows why you people enjoy foods that have sauces or glazes on top of them.
The result of that knowledge is that foods that promote salivation do a happy little tap dance on your brain and taste better than ones that don’t.
Rapid food meltdown and vanishing caloric density. Foods that rapidly vanish or melt in your mouth signal to your brain that you’re not eating as much as you actually are. In other words, these foods literally tell your brain that you’re not full, even though you’re eating a lot of calories.
Next thing you do, you overeat.
Many food scientists take Cheetos as a perfect representative of this “quality”.
Cheetos has a dozen attributes that make the brain say: MOOOORE. Insert. Food. Here.
points to the hole in your face lat. cavitas oralis aka human mouth


But the one attribute Cheetos has is this puff’s uncanny ability to melt in the mouth — vanishing caloric density. If something melts down quickly, your brain thinks that there’s no calories in it, so dear friend, you can just keep eating it forever.


Sensory-specific response.

Your brain likes variety. When it comes to food, if you experience the same taste over and over again, then you start to get less pleasure from it. In other words, the sensitivity of that specific sensor will decrease over time. This can happen in just minutes.
Junk foods, however, are designed to avoid this sensory-specific response. They provide enough taste to be interesting (your brain doesn’t get tired of eating them), but it’s not so stimulating that your sensory response is bored or dulled. Never wonder why you can literally swallow an entire bag of potato chips or bucket of popcorns and still be ready to eat a few bags or buckets more. After all, serious science is behind it. To your brain, the crunch and sensation of eating Pringles are new and interesting every single time.


Calorie density.

Junk foods are designed to convince your brain that it is getting nutrition, but not enough to fill you up.


The receptors in your mouth and stomach tell your brain about the mixture of proteins, fats, carbohydrates in a particular food, and how filling that food is for your body. Amazing, right?


Junk food provides just enough calories that your brain says: “Yes, this will give you some energy” but not so many calories that you go: “That’s enough, I’m full.”


In the end, you crave the food, to begin with, but it takes quite some time to feel full from it, even though from the calorie intake stand, you are more than okay to stop a long time ago.


Memories of past eating experiences. This is where the psychobiology of junk food really works against you. When you eat something tasty (say, a french fries), your brain registers that feeling. The next time you see that food, smell that food or even read about that food, your brain starts to trigger the memories and responses that came when you ate it. These memories can actually cause physical responses like salivation and create the mouth-watering craving you get when thinking about your favorite foods.


All of this brings us to the most important question of all.
What should we do with it? It is a sort of manipulation, but boy it is sinful tasteful food we’re talking about here. It will almost certainly kill us in the end (whenever that is), but not before other human-made destroying machines like climate change, narcotics or reality shows.


In the name of pizza, fries, hot-dogs, ice-cream, and chips: crunch-crunch!

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