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Why is junk food so addictive?

If you’ve found yourself asking this question, you’re not alone. Junk food is addictive, there’s no doubt about that. But understanding the science behind the ‘why?’ is a great first step in getting rid of food addiction for good.
Jessica Sutcliffe
5/5/2022
16
min read
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Quick summary

  • Junk food is any food that provides little to no nutritional content, but is high in calories
  • Just like alcohol and drugs, junk foods trigger the pleasure and reward centres of your brain and release large amounts of ‘happy’ chemicals such as dopamine
  • The more we eat junk foods, the more our brains attempt to regulate our dopamine levels so we become reliant on food for those good feelings
  • Overindulgence in junk foods can lead to weight gain and obesity, and can cause spikes in blood sugar levels that are especially harmful for people with type 2 diabetes

If you want to work out how to overcome food addiction, the best place to start might actually be on your phone. Most of us will have at least one app that lets us get our favourite takeaways delivered straight to our door, and the ease of ordering online can be just another reason why that fix is so hard to kick. It’s no secret that of all the foods, junk food—which is food that has very little or no nutritional content—is the most addictive. But, the real question is why? 

The science behind junk food addiction

The key to answering this is a little thing called dopamine. To get technical for a minute, dopamine is a neurotransmitter that sends chemical messages from your brain to the rest of your body.[1] It’s sometimes known as a ‘happy’ chemical because it’s associated with your sense of pleasure and reward.[2] The feeling that left you grinning from ear to ear when you heard your favourite song, earned that promotion at work, or watched your team score: dopamine had something to do with that. But dopamine itself isn’t the problem, it’s actually a very important part of maintaining a healthy body. The reason things get complicated is that dopamine is also used by our brains for reinforcement: when something makes us feel good, we want to do it again, and again, and again.[3]

For some people, the pleasure and reward centres of the brain light up for food

As we continually seek out behaviours that give us that happy feeling, we ultimately begin to build habits. Unfortunately, the more we repeat the behaviour, the more our brains adjust to the increased levels of dopamine, regulating the highs by toning down your body’s natural dopamine production.[4] This means that to get the same high we have to do that same activity more and more. Changes in dopamine receptors due to over-activation of our ‘happy’ chemical also breaks down your resistance as you begin to lose interest in other activities.[5] And of course, because we’re a naturally curious species, human beings have learned that ingesting certain things can cause very intense dopamine releases which magnify the whole process and —ultimately—lead to addiction. Drugs like alcohol or cocaine can create a huge feeling of reward because of the extreme levels of dopamine that are released in the brain, and that’s what makes them so addictive.

However, for some people the same pleasure and reward centres of the brain that light up when you take drugs, can also light up for food.[6] This is particularly true of foods that are rich in sugar, fats, and salt: junk foods. Just like addictive drugs, junk foods trigger those same ‘happy’ chemicals. And just like everything else that gives you that dopamine high: the more you have it, the more you want it. Cravings are a huge part of the food addiction cycle, and whether you’re living with type 2 diabetes or not they’re an important thing to pay attention to. 

How does this impact me if I have type 2 diabetes?

We all have food cravings now and again, and although sometimes they might be signalling that your body is lacking in certain nutrients, more often than not they’re caused by a complex combination of hormones, food routine, and emotional factors. Cravings can also be caused by spikes in your blood sugar levels—after eating, your blood sugar levels rise rapidly as the glucose in your food is absorbed into your bloodstream. Insulin is then produced to ferry that glucose around your body and deposit it as fuel along the way. As that happens your blood sugar levels regulate again, which can cause a dip in your mood. Sometimes this might mean you feel sleepy or struggle to concentrate after a meal, and sometimes it can leave you craving more food that’s rich in glucose. 

For people with type 2 diabetes, the body doesn’t produce enough insulin, or it doesn’t always respond properly to the rise in blood sugar. This means that blood sugar levels can continue to rise, or stay elevated for longer after eating, because it takes longer for the insulin to get the fuel to where it needs to be. When you combine this with a junk food addiction, because junk food is rich in carbohydrates and sugars, it can cause significantly high blood sugar levels for sustained periods of time which ultimately increases the likelihood of complications in the body.

So the same sweet, salty, and rich foods that are so effective at activating neurotransmitters in the pleasure centres of the brain can actually be very damaging to your overall health. And not only do they ordinarily not include a huge amount of nutritional benefit, but the intensity of the dopamine high can even override your body’s signals of fullness and satisfaction.[7] Ever felt full but kept eating because it just tastes so good? We all have, and that’s why junk foods can be so harmful. All of this contributes to the cycle of addiction, as when we lose sight of our bodies’ ways of telling us we’re full, our portion sizes tend to grow too. There’s even evidence to suggest that these kinds of foods are designed to make us feel this way and that food companies prioritise addictive elements of their products over the nutritional value they contain. And, the more we reach for those treats, the less they satisfy us, meaning we want more, more often, to hit the spot. Entire books have been written about the fast-food industry engineering delicious-tasting food that takes over our brain circuitry in this way: encouraging us to overeat and fuelling a global epidemic of chronic diseases such as type 2 diabetes.[8] 

When you lay it all out, it’s easy to see how junk food addiction can play an important part in weight gain, obesity, and type 2 diabetes. Now we know that it’s the high levels of sugar, salt, and fat in junk foods that makes them incredibly addictive...and they’re usually high in calories too. To make matters worse, the low nutritional content of these types of food means we get very little—if any—nutritional or health benefit from eating them. If you’re living with type 2 diabetes, this can be dangerous because the sugar content of most junk foods will be having a significant negative effect on your blood sugar levels: so overcoming your junk food addiction is even more important.

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How to overcome addiction to junk food

But, time for the good news! By understanding how it all works, you’re already one step toward getting rid of food addiction for good—and kicking your junk food habit is a great place to start. You could delete those apps right now… but the journey to building a better relationship with food goes beyond that. For some people looking to beat their addiction, going ‘cold turkey’ is a great strategy. But all humans need food to survive, so the approach we take needs to be different. If you want to get started but want a bit of help, why not try our five key steps to overcoming food addiction.

Reinvent a healthy relationship with food

1. Recognise addictive urges as dysfunctional thoughts

The first step is to identify your craving in the moment and go through a bit of a thought exercise. Next time you find yourself dreaming of your favourite snack, take a minute to have a chat with your brain. It doesn’t have to be anything more than saying to yourself ‘Right now, I’m craving food that my body doesn’t need’. It won’t stop you wanting it, and that’s totally okay. But it will begin to reframe the addictive thoughts from an urgent need, to an unnecessary desire.

2. Practise compassion by being objective

The reality of it is that our addictive thoughts are just that: thoughts. They are created by our brains. So in this step, start attributing the blame where it belongs. Rather than beating yourself up about your cravings, try being compassionate with yourself. Rather than thinking ‘I’m not strong enough to resist the urge’, we can instead think ‘my brain chemicals are telling me I need this thing because that’s what they’re wired to do, and I know that this happens when I’m stressed/bored/upset/tired.’ The aim is to stop accusing yourself with thoughts like ‘why can’t I control myself?’ and start understanding what actually triggers these actions in your body. This actually has a name: conscious awareness.

3. Postpone your urges

In this step, you’re going to begin teaching your brain that you don’t always need to listen to the cravings. Next time your brain is sending you those messages, try and refocus your mind on something else enjoyable. Maybe you’re reading a great book, or you’ve been meaning to call your best friend for a catch-up—whatever it is you love doing, take the opportunity when your next craving strikes to show yourself that you don’t have to give into urges straight away. It doesn’t mean not getting to enjoy the thing you’re dreaming of, it just means delaying your gratification to show your brain who’s boss. The key thing is there is now a choice, where perhaps before you couldn’t see one.

4. Think beyond the satisfaction

This one is about thinking through the process of satisfying your craving. The aim is to reassign the thing you’re desiring with a value that’s actually realistic. When we crave a thing, we tend to give it a much higher value than it probably deserves. We feel like it will solve all our problems, make us feel infinitely happier… but the reality is it probably won’t. By thinking beyond the initial satisfaction (I’m eating what I want to eat) you’re asking yourself ‘what has this addictive urge done for me?’; ‘how does it make me feel after the fact?’ and even ‘what have been the longer-term impacts of taking part in this behaviour— are they good or bad?’.

The most important thing to remember when you’re doing this is not to judge or reprimand yourself when you think through the process and ask yourself those questions. It’s not about making yourself feel guilty, it’s about engaging yourself in a conversation about how it feels when you succumb to a craving. Over time this will help you recognise the real value of the foods your brain is urging you to eat.

5. Grow past your cravings

The final step to overcoming your food addiction is to decide who you want to become as you move beyond your cravings. It’s about showing yourself how overcoming your addictive urges fits into the person you’re becoming. You’re developing the strength to battle with your addiction, and you can use that strength to move toward a life, and identity, you desire. Our advice is to put it down on paper so you can refer back to it every time your brain is giving you those pesky thoughts of sugary snacks.

You'll may need to repeat these steps over and over as you build habits that help direct your brain away from craving junk foods. Identity-based habits can be really powerful tools to guide you toward a healthier life, but they take dedication and compassion. You may not get it right first time— and that’s okay— but stick at it, and you’ll feel the changes!

So let’s sum things up

Why is junk food so addictive? Because its high quantities of sugar, salt and fat tap right into the pleasure and reward systems in our brains. The dopamine that’s released when you bite into a chocolatey snack gives you a rush that you want to repeat over and over again. This forms a habit and creates blood sugar spikes that cause cravings. To counteract all the extra dopamine we’re getting from our food, our brains then stop making as much of it and we become more reliant on junk food to feel good. Other things happen too, like our signals for fullness are overridden by our cravings. Because junk foods tend to be low in nutritional content, but high in calories, this cycle of addiction contributes to weight gain, obesity and diseases like type 2 diabetes which can have a significant negative impact on your life. 

If this shows us anything, it shows us why today is a great day to find out how to break food addiction. As well as our plan to overcome food addiction, we have a few other resources you might find helpful:

Good luck!

References

[1] What is dopamine? WebMD. Retrieved 15 March 2022. Accessible here.

[2] Dopamine: Role, Related Conditions, and Treatments. Very Well Health. Retrieved 14 March 2022. Accessible here.

[3] Wise, R. A.. (2006). Role of brain dopamine in food reward and reinforcement. Phil Trans R Soc B 361(1471):1149-1158. Accessible here.

[4] How does dopamine affect the body?. Healthline. Retrieved 15 March 2022. Accessible here.

[5] How does dopamine affect the body?. Healthline. Retrieved 15 March 2022. Accessible here.

[6] Food addiction. WebMD. Retrieved 14 March 2022. Accessible here

[7] Food addiction. WebMD. Retrieved 14 March 2022. Accessible here

[8] This is your brain on junk food. The New York Times. Retrieved 14 March 2022. Accessible here.

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