But if it’s so bad for us,
why do we keep doing it?
There is an answer. And the
science behind it will surprise you.
Why We Crave Junk Food
According to Witherly, when
you eat tasty food, there are two factors that make the experience pleasurable.
First, there is the
sensation of eating the food. This includes what it tastes like (salty, sweet,
umami, etc.), what it smells like, and how it feels in your mouth. This last
quality — known as “orosensation” — can be particularly 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.
The second factor is the
actual macronutrient makeup of the food — the blend of proteins, fats, and
carbohydrates that it contains. In the case of junk food, food manufacturers
are looking for a perfect combination of salt, sugar, and fat that excites your
brain and gets you coming back for more.
Here’s how they do it…
How Science Creates Cravings
There are a range of factors
that scientists and food manufacturers use to make food more addictive.
Dynamic contrast. Dynamic contrast refers to a combination of different sensations
in the same food. In the words of Witherly, foods with dynamic contrast have:
… 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 creme brulee, a slice of pizza, or an Oreo cookie — the
brain finds crunching through something like this very novel and thrilling.
Salivary response. Salivation is part of the experience of eating food, and the more
that a food causes you to salivate, the more it will swim throughout your mouth
and cover your taste buds. For example, emulsified foods like butter,
chocolate, salad dressing, ice cream, and mayonnaise promote a salivary
response that helps to lather your taste buds with goodness. This is one reason
why many people enjoy foods that have sauces or glazes on them. The result 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.
The result: You tend to
overeat.
In his best-selling
book Salt Sugar Fat, author Michael Moss describes a conversation
with Witherly that explains vanishing caloric density perfectly…
I brought him two shopping bags filled with a
variety of chips to taste. He zeroed right in on the Cheetos. “This,” Witherly
said, “is one of the most marvelously constructed foods on the planet, in terms
of pure pleasure.” He ticked off a dozen attributes of the Cheetos that make
the brain say more. But the one he focused on most was the puff’s uncanny
ability to melt in the mouth. “It’s called vanishing caloric density,” Witherly
said. “If something melts down quickly, your brain thinks that there’s no
calories in it … 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 dulled. This is why you can swallow
an entire bag of potato chips and still be ready to eat another. To your brain,
the crunch and sensation of eating Doritos is novel and interesting every time.
Calorie density. Junk foods are designed to convince your brain that it is getting
nutrition, but to not fill you up. 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. Junk food provides just
enough calories that your brain says, “Yes, this will give you some energy,” but
not so many calories that you think, “That’s enough, I’m full.” The result is
that you crave the food to begin with, but it takes quite some time to feel
full from it.
Memories of past eating experiences. This is where the psychobiology of junk food really
works against you. When you eat something tasty (say, a bag of potato 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 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 that
you get when thinking about your favorite foods.
All of this brings us to the
most important question of all.
Food companies are spending
millions of dollars to design foods with addictive sensations. What can you and
I do about it? Is there any way to counteract the money, the science, and the
advertising behind the junk food industry?
How to Kick the Junk Food Habit and Eat Healthy
The good news is that the
research shows that the less junk food you eat, the less you crave it. My own
experiences have mirrored this. As I’ve slowly begun to eat healthier, I’ve
noticed myself wanting pizza and candy and ice cream less and less. Some people
refer to this transition period as “gene reprogramming.”
Whatever you want to call
it, the lesson is the same: If you can find ways to gradually eat healthier,
you’ll start to experience the cravings of junk food less and less. I’ve never
claimed to have all the answers (or any, really), but here are three strategies
that might help.
1. Use the “outer ring” strategy and the “5 ingredient rule” to buy
healthier food.
The best course of action is
to avoid buying processed and packaged foods. If you don’t own it, you can’t
eat it. Furthermore, if you don’t think about it, you can’t be lured by it.
We’ve talked about the power
of junk food to pull you in and how memories of tasty food in the past can
cause you to crave more of it in the future. Obviously, you can’t prevent
yourself from ever thinking about junk food, but there are ways to reduce your
cravings.
First, you can use my “outer ring” strategy to avoid processed and packaged foods at the
grocery store. If you limit yourself to purchasing foods that are on the outer
ring of the store, then you will generally buy whole foods (fruits, vegetables,
meat, eggs, etc.). Not everything on the outer ring is healthy, but you will
avoid a lot of unhealthy foods.
You can also follow the “5
ingredient rule” when buying foods at the store. If something has more than 5
ingredients in it, don’t buy it. Odds are, it has been designed to fool you
into eating more of it. Avoid those products and stick with the more natural
options.
As we covered earlier, the
brain craves novelty.
While you may not be able to
replicate the crunchy/creamy contrast of an Oreo, you can vary your diet enough
to keep things interesting. For example, you could dip a carrot (crunchy) in
some hummus (creamy) and get a novel sensation. Similarly, finding ways to add
new spices and flavors to your dishes can make eating healthy foods a more
desirable experience.
Moral of the story: Eating
healthy doesn’t have to be bland. Mix up your foods to get different sensations
and you may find it easier than eating the same foods over and over again. (At
some point, however, you may have to fall in love with boredom.)
3. Find a better way to deal with your stress.
There’s a reason why many
people eat as a way to cope with stress. Stress causes certain regions of the
brain to release chemicals (specifically, opiates and neuropeptide Y). These
chemicals can trigger mechanisms that are similar to the cravings you get from
fat and sugar. In other words, when you get stressed, your brain feels the
addictive call of fat and sugar and you’re pulled back to junk food.
We all have stressful
situations that arise in our lives. Learning to deal with stress in a different
way can help you overcome the addictive pull of junk food. This could
include simple breathing techniques or a short guided
meditation. Or something more physical likeexercise or making art.
With that said, if you’re
looking for a better written and more detailed analysis of the science of junk
food, I recommend reading the #1 New York Times best-seller Salt
Sugar Fat.
Where to Go From Here
see donportercancer
One of my goals with this
article is to reveal just how complex poor eating habits can be. Junk food is
designed to keep you coming back for more. Telling people that they “need more
willpower” or should “just stop eating crap” is short-sighted at best.
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