What Happens to Your Brain When You Cut Back on Sugar, According to a Neuroscientist

Better sleep, right this way

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what happens to your brain when you quit sugar
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In a perfect world, we’d be able to eat as many sweets as we want—whenever we want them—without any consequences. In reality, however, we know that’s just not possible. While we’d love to end each night with a couple slices of sticky toffee honeycomb cake or chocolate glazed espresso cheesecake, we’re pretty aware of the adverse effects of excess sugar. But still, sweet treats can feel really hard to resist at times, which is why we reached out to neuroscientist Dr. Nicole Avena, an expert in the field of food addiction, to learn what happens to our brains when we eat less sugar—you know, as motivation to think twice about that venti double chocolaty chip crème Frappuccino.  

Meet the Expert

Dr. Nicole Avena, Ph.D., is a research neuroscientist, author and expert in the fields of nutrition, diet and addiction. She has a Ph.D. in Neuroscience and Psychology from Princeton and completed her postdoc in molecular biology at Rockefeller. She is an Associate Professor of Neuroscience at Icahn School of Medicine at Mount Sinai and a Visiting Professor of Psychology at Princeton University. Avena is the author of several books including Sugarless: A 7-Step Plan to Uncover Hidden Sugars, Curb Your Cravings, and Conquer Your Addiction

What Happens to Your Brain When You Cut Back on Sugar? 

Avena admits that while it's tough to resist sweet treats, especially because they provide instant gratification, “cutting down on added sugar can lead to remarkable brain changes.” Here’s what happens when you decide to dial back on the sugar intake.

  • Dopamine Regulation: You know that rush of pleasure you get when you indulge in something sweet? That's caused by dopamine, a neurotransmitter associated with reward and pleasure. Avena explains, “Sugar activates the brain’s reward system, which is why sugar is so addictive. Excessive sugar consumption can lead to a dysregulation of dopamine release, like what happens with addictive substances. But by cutting down on sugar, you're helping your brain recalibrate its reward system, leading to reduced cravings and a healthier relationship with food.”
  • Cognitive Clarity: Avena tells us that high sugar intake has been linked to inflammation in the brain, which can impair cognitive function and lead to brain fog. By eating less sugar, you're reducing that inflammation, which can result in improved mental clarity, sharper focus and better memory retention. 
  • Stable Blood Sugar: “No more rollercoaster ride of energy crashes and sugar highs,” Avena shares, adding that by cutting down on sugar, you're helping to stabilize your blood sugar levels, leading to fewer mood swings, more consistent energy and better overall mood regulation. 
  • Reduced Anxiety: That sleeve of Oreos might make you feel good in the moment, but it could also be causing anxiety. Avena says, “Sugar can cause erratic fluctuations in blood glucose levels, and poor glycemic control is associated with higher levels of anxiety.” (There’s more on this in her book, Sugarless: A 7-Step Plan to Uncover Hidden Sugars, Curb Your Cravings, and Conquer Your Addiction.) This is also related to the connection between the brain and the gut. Per Johns Hopkins Medicine, there's a "little brain" in the gut that scientists call the enteric nervous system (ENS), which is two thin layers of more than 100 million nerve cells lining your gastrointestinal tract from esophagus to rectum. Researchers have found evidence that irritation in the gastrointestinal system may send signals to the central nervous system (CNS) that trigger mood changes. “The gut and brain communicate through the gut-brain axis,” Avena tells us. “Basically, too much added sugar alters the gut microbes, which compromises communication to the brain and increases inflammation, in turn impacting mental health and anxiety levels.” 
  • Improved Sleep Quality: It’s no surprise that what you eat can impact your sleep, and excessive sugar consumption can disrupt your sleep-wake cycle and lead to restless nights. “By reducing sugar intake, you're creating a more stable environment for sleep,” Avena says. “Without the spikes and crashes in blood sugar levels, you'll experience fewer disruptions to your sleep patterns, leading to more restful and rejuvenating sleep.” 
how to quit sugar
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How to Cut Back on Sugar Successfully and Sustainably

Now that you’ve heard about how cutting out—or at least back on—sugar can have some pretty profound benefits, you might be wondering how to effectively scale back your sugar consumption long-term. Avena has a few tips for tackling this challenge: 

  • Be More Mindful of Sugar Consumption: Avena says the first step is to become more aware of where sugar lurks—which can be tricky because it’s not always obvious, since many foods that appear healthy are secretly loaded with sugar. “Start by reading labels and identifying hidden sugars in processed foods and beverages,” Avena advises. “By knowing what you're putting into your body, you can make more informed choices and gradually reduce your sugar intake.”
  • Add Probiotic and Prebiotic Supplements to Your Routine: We heard above about the connection between the brain and the gut. Cutting back on sugar is the first step in creating a healthy gut and brain, and Avena says the next step is adding probiotic and prebiotic supplements to help your gut and brain health into your daily routine. She recommends Jarrow Formulas Saccharomyces Boulardii + MOS
  • Reduce Sugar in Moderation: “Rome wasn't built in a day, and neither is a sugar-free lifestyle,” Avena admits. “Instead of going cold turkey, focus on gradually reducing your sugar consumption. Start by cutting back on sugary snacks and desserts, and gradually replace them with healthier alternatives like fruits, nuts or dark chocolate.”
  • Introduce Nutritious Substitutions: Healthy eating doesn’t have to be boring. As you reduce your sugar intake, try experimenting with nutritious alternatives, whether that means swapping out soda for sparkling water or opting for a piece of fruit instead of a candy bar. Avena adds that eating nutritious, non-starchy vegetables like tomatoes and cucumbers will support healthy blood sugar levels and can help you avoid cravings. “Additionally, to help improve cognitive clarity and focus, try eating more sweet potatoes, as they contain an inactive form of vitamin A known as carotenoids. Carotenoids have the power to improve our cognitive function over time.”
  • Get Your Beauty Sleep: Per Avena, you should aim for seven to nine hours of quality sleep each night and establish a consistent sleep schedule to support your efforts in cutting down on sugar. “Quality sleep not only helps regulate appetite hormones but also enhances willpower and decision-making, making it easier to resist unhealthy food choices,” she explains, while also recommending adding supplements like Jarrow Formulas Sleep Optimizer, which combines herbs and amino acids to help you fall asleep and support a regular sleep cycle. 

sarah stiefvater

Wellness Director

Sarah Stiefvater is PureWow's Wellness Director. She's been at PureWow for ten years, and in that time has written and edited stories across all categories, but currently focuses...