January 23, 2024, 8:45 am | Read time: 12 minutes
Few would argue that a consistently excessive consumption of sugar can harm health. Yet many struggle to limit their intake of sweets or foods containing sugar. So why is it so hard for us to give it up? Nuno Alves interviewed U.S. neuroscientist and nutrition expert Dr. Nicole Avena about the addictive potential of sugar, the symptoms of dependency, and withdrawal symptoms.
Dr. Nicole Avena is a neuroscientist, nutrition expert, and assistant professor at the elite U.S. university Princeton, researching food addiction and its consequences for years. She has summarized her findings in the book “Why Diets Fail (Because You’re Addicted to Sugar).” She also appears in the Netflix documentary “You Are What You Eat: A Twin Experiment.” In an interview with FITBOOK, Avena explains why sugar addiction is similar to drug or alcohol addiction, why she advises against going cold turkey, and how to avoid relapses.
FITBOOK.de: Many claim that craving sweets is a sign of weakness. What is your view?
Dr. Nicole Avena: “I would say it’s not a sign of weakness. Craving sugar is far more complex than just lacking the willpower to avoid it. When you eat highly processed foods, which typically have a high sugar content, the brain releases dopamine—creating an ultimate reward signal. When high amounts of dopamine are released due to sugar, it makes us feel good about what we’ve just eaten. And our brain tells us we want more of it. This often leads us to overeat or crave something sweet.”
»Companies Exploit Our Biology
Why does dopamine get released at all with sweets?
“From an evolutionary perspective, it’s advantageous. When we were hunter-gatherers, finding tasty food in an environment otherwise marked by food scarcity allowed us to understand that we should eat a lot of it because it was unclear when the next meal would be available.”
Most people today don’t live as hunter-gatherers…
“Nowadays, food is anything but scarce, and our food supply is instead oversaturated with products containing excessive amounts of sugar. You could say that companies exploit our biology, making us want to buy their sugary products.”
How Sugar Overloads the Reward System
Is there scientific evidence that sugar has addictive potential?
“Absolutely. We know that sugar causes dopamine release in the brain, creating a positive feedback loop. This leads to reward-driven eating behavior, also called ‘hedonic eating.’ We eat because it makes us feel better, not for the calories or nutrients. Overloading the reward system—whether through sugar or drugs like cocaine, nicotine, or alcohol—drives people to seek the high they get from dopamine release.”
One becomes somewhat sugar-addicted…
“A substantial amount of evidence—much of it from my lab—shows that consuming highly processed foods rich in added sugars, like ice cream, cookies, or even pizza, can lead to brain changes over time. These are comparable to being addicted to drugs or alcohol. This is partly why it can be challenging to maintain a healthy diet. We’re addicted to junk food and need more to get the same dopamine response. Studies with lab animals support the hypothesis that highly processed foods, especially those with high amounts of added sugar, can be addictive. Additionally, neuroimaging studies (using imaging techniques, editor’s note) show that the reward system in overweight individuals exhibits changes similar to those in drug-addicted people.”
Also interesting: How Junk Food Manipulates Our Brain
The Symptoms of Sugar Addiction
Are there symptoms of sugar addiction?
“Signs can include never feeling full when eating healthy foods or feeling like you could overeat to feel satisfied. You may be irritable and in a bad mood during a diet, and constantly crave certain foods. Some researchers also believe that binge eating is a sign of food addiction. Binge eating involves consuming unusually large amounts of food in a short time. This behavior has been extensively studied in rats to show that an addicted individual might overeat just as they would overconsume alcohol.”
What do you advise people who believe they are sugar-addicted?
“If you feel the above description applies to you, try to reduce or eliminate sugar. Although it’s impossible to eat 100% sugar-free—even healthy foods like fruits or vegetables contain sugar—you should find ways to cut down on added sugar and reconsider sugar’s role in your life. Changing your diet so that sugar isn’t the main source of pleasure and calories also means cutting unnecessary carbohydrates and integrating complex carbohydrates. Depending on how dependent you are on sugar, something sweet like a donut might be okay occasionally, but pasta or brown rice now and then doesn’t hurt either. Ultimately, it’s about ensuring added sugar doesn’t control your eating behavior.”
Also interesting: 6 Symptoms That Show You’re Eating Too Much Sugar
Tips to Avoid Sugar Addiction
How can you prevent developing a sugar addiction?
“As with everything in our diet, whether healthy or not, moderation is key. Occasionally having something sweet is not a big deal, but if you notice you’re overdoing it with sweets every time—for example, eating a 500-milliliter tub of ice cream in one go, or following one donut with a second and third—then you should take a step back. You should look for other ways to enjoy sweets without overloading your dopamine system.”
For example?
“Keep fresh fruit and cut-up vegetables handy as snacks when you feel the need for something. If you want ice cream, go out for a scoop instead of bringing home a 500-milliliter tub or more from the supermarket. Find ways to limit your consumption and create obstacles so you can’t overdo it.”
The Withdrawal Symptoms of Sugar
What are typical withdrawal symptoms of sugar?
“Research on lab animals shows that withdrawal symptoms can be the same as with drugs. These include anxiety and depression. Another good indicator of sugar withdrawal symptoms is if you’re irritable and in a bad mood during a diet and constantly crave sweet foods.”
What should one expect when trying to quit sugar?
“Like any addiction, the recovery process can be difficult—but recovery is possible. With sugar addiction, it might be best to gradually eliminate addictive foods from your diet. For example, you can start by cutting out all sugary drinks, then sweets, and so on. From this point, it will be challenging to completely eliminate sugar from your life, but each step will become a bit easier over time. Even after overcoming a sugar addiction, you must always be mindful of your diet and prevent falling back into old habits—whether eating out or in the pantry.”
»I Advise Against Going Cold Turkey on Sugar Addiction
Is a radical change from one moment to the next advisable?
“Many try going cold turkey and cut out sugar entirely. I advise against it because it can be physically and mentally challenging to stay away from sugar when you change your diet so abruptly. This can lead to further binge eating—and ultimately mean a complete restart on a journey you’ve worked so hard for.”
What else do you recommend?
“You should first identify the main source of added sugar in your diet and start there. It’s important to learn how to read food labels and interpret ingredients to understand where added sugars might be hiding. You should reduce and replace, not deprive.”
In your book “Sugarless,” you describe a step-by-step plan to reduce or eliminate added sugar…
“In the book, I discuss what I call the ‘Seven Simple Steps,’ where I give readers tricks and tips on how to assess their sugar addiction status and overcome cravings. It’s not a ‘Do this, not that’ approach but a scientifically based guide to reducing overall sugar consumption, which positively impacts mental and physical health in the long run.”
What do these steps specifically involve?
“The first steps involve accepting that you’re sugar-addicted and determining where exactly you fall on the spectrum. Then it addresses the psychological factors influencing sugar consumption, including triggers and learned behaviors related to sweets. The final steps closely examine what’s in daily foods. From drinks to frozen meals—hidden sugar is everywhere, making us addicted!”
The role of the reward system and the impact of highly processed foods on our eating behavior are also subjects of research on healthy aging. Nuno Alves explores these connections in his book “Highway to Health – In 7 Steps to a Healthy Long Life”, set to be released on January 4, 2027, which also features neuroscientist Dr. Nicole Avena.
How to Avoid a Relapse After Sugar Addiction
What should be considered to avoid a relapse after overcoming sugar addiction?
“It might be easier to view sugar addiction like alcohol dependency. A true alcoholic won’t take even a sip of alcohol when trying to overcome the addiction and stay sober. Even a small sip of alcohol can make a person feel like they’re losing control over their drinking and quickly relapse. For someone who truly believes they’re sugar-addicted, just one sweet treat can negatively impact maintaining a low-sugar diet. For example, a donut can lead to eating two or three in one go—which in turn leads to another strong craving that’s hard to ignore.”
I’ve been avoiding foods with added sugars since 2018. That means no sweets. Some think I’m no fun because of it. Do you believe there’s social pressure associated with eating sweets?
“I think sweets are often associated with reward and nostalgia—and those who abstain are often criticized for ‘not having fun.’ In reality, society and big food companies have programmed us to see these foods as normal. This way, we become and remain addicted. We know sugar harms our health and can cause a host of lifestyle diseases. To those who look critically at you for declining a sweet treat from a friend or family member, I advise: Share your knowledge about why avoiding sugar positively impacts health and well-being.”
Many parents seem to have no problem giving their children sugary foods and drinks, even though it significantly increases the risk of obesity, diabetes, high blood pressure, and even diseases like cancer…
“We’ve been taught that good behavior in school leads to dessert after dinner or a won soccer game means ice cream. The American Academy of Pediatrics recommends avoiding added sugar in the first two years of life—so why not stick to it! Children, like adults, develop a tolerance for the amount of sugar they need to feel satisfied. If we start viewing sugar as an addictive substance and as something that shouldn’t be part of children’s daily meals, they’ll have a very low tolerance and little to no craving for it.”
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»Governments Must Recognize That Sugar Is Addictive
Some countries have introduced taxes on sugary drinks—a measure recommended by the World Health Organization (WHO). Is this the right measure?
“I think one of the only ways to truly change societal views on sugar is to bring it into politics. Once sugar is recognized as an addictive substance, as is the case with cocaine and alcohol, it will become clear how important it is to banish it from our lives. I believe people are very capable of making informed health decisions for themselves—including what they want to eat and drink. What we overlook is that sugar is addictive—unlike other activities or foods that impair public health. Governments need to recognize this and change policies regarding the amount of sugar allowed in major brand products.
Do you think this will happen soon?
“Given the immense sums of money involved in industrial agriculture and corporate food systems, I’m not sure.”
On the Pros and Cons of Sweeteners
Those looking to reduce sugar often turn to sweeteners. What do you think of them?
“Sweeteners like stevia or erythritol can be good alternatives when trying to consume less sugar. Especially when the goal is to reduce overall calories and blood sugar spikes. However, sweeteners still have a sweet taste and trigger a dopamine reward response, which can be detrimental if the goal is to reduce sugar dependency overall. Ideally, you would find ways to enjoy sweets in moderation. For example, you can opt for fruit snacks instead of candies and pastries. Or buy pre-portioned products to avoid overeating. Choose fiber-rich grains and legumes, such as whole grains, lentils, or beans, and replace processed grains like rice, pasta, or white bread.”
The taste buds surely need time to adjust too…
“Often, food tastes sweet because of the sauces or seasonings we add. Instead of buying sugary dressings, you can experiment with spices and herbs to give food extra flavor and sugar-free zest. A few splashes of lemon or lime on food can also be a good way to add a natural dressing. You might notice that your taste buds will change, and you’ll prefer sugar-free flavors the more you make your own dressing or experiment with seasoning meals.”
Also interesting: NEOH Founder Manuel Zeller: “I’m the Biggest Sugar Junkie Myself”
What is your personal relationship with sugar?
“I don’t eat much of it. I’ve never snacked much, so it’s not a big challenge for me. Because of my research, I’m more aware of the dangers of excessive sugar consumption, so I prefer to avoid it.”