Why We Crave Junk Food and What to Do About It

You know that Twinkie isn’t healthy and you really don’t need that mid afternoon bag of chips but you eat it anyway.  We all know junk food is unhealthy but that just doesn't stop us from munching away.

There is a good reason why we crave junk food.  The psychobiology of junk food works against us by using our memories of past eating experiences.  When you eat something tasty (like a bag of chips), 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 memories and responses from the time you ate it. These memories cause physical responses like salivation and create the “mouth-watering” craving you get when thinking about your favorite foods.

We all know that junk food is unhealthy.  Poor nutrition is related to heart problems, high blood pressure and many other health ailments.  Some studies even show that eating junk food has been linked to depression.

A report by food scientist Steven Witherly supports the junk food craving.  According to Witherly, when you eat tasty food, there are two factors that make the experience pleasurable.

The sensation of eating the food is one.  This includes what it tastes like (sweet, salty, etc.), how it feels in your mouth and what it smells like.  Food companies spend millions of dollars in order to discover the most satisfying level of crunch in a potato chip or the perfect amount of fizz in a cola. Combined, these factors create a sensation that your brain associates with a particular food or drink.

The actual makeup of the food is the second factor.  This includes the blend of proteins, fats and carbohydrates contained in it.  When developing junk food, manufacturers look for the perfect combination of sugar, salt and fat which will excite your brain and hook you into coming back for more.

They do this by creating cravings with a range of factors that make food more addictive.

The first of these is dynamic contract. This refers to a combination of different sensations in the same food.

Witherly describes dynamic contrast as “an edible shell that goes 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 Crème Brule, slice of pizza or an Oreo cookie—the brain finds crunching through something like this very novel and thrilling.”

Next is salivary response.  The more that a food causes you to salivate, the more it will swim through your mouth and encase your taste buds.  Examples of these kinds of foods include butter, salad dressing, ice cream, butter and mayonnaise. This is one of the reasons why people enjoy foods with glazes or sauces.  Your brain is happier with foods that taste better than the ones which don’t.

The trickiest factor is the rapid food meltdown and vanishing caloric density.  These foods that basically melt in your mouth signal your brain that you are not eating as much as you really are.  Your stomach may be full but your brain doesn’t believe it. The result, of course, is that you overeat.

According to Witherly a perfect food example of this is Cheetos.  There are more than a dozen attributes that make the brain ask for more but the one he concentrates on is vanishing caloric density.

“If something melts down quickly, your brain thinks there are no calories in it…you can just keep eating it forever,” says Witherly.

When it comes to food, the brain likes variety.  You get less pleasure from tasting the same thing over and over.  This is called sensory specific response and can happen in moments.

Smart manufacturers know how to design junk food to avoid this sensory specific response. They give you just enough taste to keep your brain from being tired of eating a product but not enough stimulation to dull your sensory response.  This is why you can eat an entire bag of potato chips and still be ready to eat another.  Thanks to modern manufacturing processes your brain perceives the sensation of eating Nacho Doritos as new and interesting every time.

Lastly, junk food is designed to persuade your brain that it is getting nutrition but not filling you up.  The receptors in your mouth and stomach tell your brain that a particular food is filling and good for your body but not enough to make you fill full from it. This is called calorie density.

So what can you do about kicking the habit of junk food when you know that food companies are throwing millions of dollars at designing foods with addictive sensations?

The first step is recognizing that you can kick the habit.  Research shows that the less junk food you eat, the less you crave it. You can find ways to gradually eat healthier and you should begin experiencing fewer junk food cravings.

Start by avoiding buying processed and packaged foods.  You are less likely to eat it if you don’t have it in your house or office.  Try purchasing whole foods like fruits, vegetables, meat and eggs.

Next, try following the five ingredient rule—if there are more than five ingredients in it, don’t buy it. Eat a variety of foods.  Your brain likes novelty.

Replace your need for crunchy/creamy contrasts.  Instead of eating an Oreo, dip your crunchy carrot into creamy hummus.  Experiment with new spices and flavors to make your healthy dishes more palatable.

Don’t let things like stress trigger your cravings for junk food.  If your feel stressed try working out, going for a walk or using simple breathing techniques to control it.


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2:00 pm-6:00 pm


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