Foods high in fats and sugars can rewire our brains to prefer junk food

Why Am I Craving Sweets? Eating Less Junk Food May Be the Solution

Why Am I Craving Sweets? Eating Less Junk Food May Be the Solution

Scientifically reviewed by: Michael A. Smith, MD

You promised yourself, "I'll just have one this time," but after a single bite of that gooey, chocolatey cookie, you knew there was no way around it: you were going to obliterate the entire bag. And then before you know it, before you can even wipe the cookie crumbs away from your lips, you're mad at yourself and have given up on any weight loss goals you might have had.

Sound familiar? When one cookie turns into a cookie-frenzy and a depleted sense of willpower, it's hard not to crank up that inner critic.

But what if this complete abandonment of your healthy eating habits wasn't your fault, but the fault of the…cookie? According to a new study published in Cell Metabolism, it's not poor self-discipline to blame, but the impact of certain types of foods on our brains that triggers cravings. The study suggests that regular consumption of calorie-rich, fatty, sugary foods directly impacts areas of the brain associated with learning and motivation, essentially rewiring our brains to favor and seek these foods over healthier, less palatable choices.

Sugar, cravings and brain signaling: What's the connection?

Researchers at the Max Plank Institute for Metabolism Research in Cologne, in collaboration with Yale University, did a randomized controlled study to see whether frequent exposure to high-fat and high-sugar foods would alter taste preferences and brain activity. Indeed, the results showed causation between diet and food preferences.

The researchers analyzed data from 49 participants who were healthy and had normal weights. They organized the participants into two randomized groups.

  1. Group 1 had 26 participants who ate a high-fat, high-sugar yogurt snack twice a day for eight weeks.
  2. Group 2 had 23 participants who consumed a low-fat, low-sugar yogurt twice daily for eight weeks.

After eight weeks, the participants returned for a final evaluation in which they were given different food options after an overnight fast. They could choose among a variety of puddings (which had different levels of fat content) and apple juices offered with differing amounts of sugar. Next, participants tasted milkshakes and tasteless solutions while hooked up to fMRI monitoring to measure brain activity.

The researchers noted several outcomes among participants in Group 1 (the high-fat, high-sugar snack group):

  • They were less likely to choose low-fat, low-sugar snacks
  • They had increased brain response to highly palatable foods like milkshakes and puddings high in fats and sugars
  • They had similar increase in fat (adipose) tissue, leptin levels and BMI as participants in Group 2

"Our measurements of brain activity showed that the brain rewires itself…. It subconsciously learns to prefer rewarding food," explained the authors of the study. They also noted that these preferences increase the risk for overeating and, eventually, weight gain.

These findings coincide with earlier preclinical results highlighting the effect Western dietary choices have on brain signaling pathways, triggering impulsivity, preference and eating frequency.

Addiction or bad habit: What are sugar cravings?

You know the feeling you get when you're walking around your grocery store and feel compelled to buy the bag of Reese's peanut butter cups? That sudden and intense urge to eat sweet foods is your body craving sugar. But are sugar cravings an outright addiction? It's tough to say. The topic is still hotly debated among experts, and there are arguments for both sides.

Let's start with the meaning of the word "addiction." According to the Merriam-Webster dictionary, an addiction denotes a compulsive, chronic, physiological or psychological need to do, use or indulge in something that has harmful effects and results in specific symptoms, such as anxiety, irritability, tremors or nausea once we stop that behavior or substance. And indeed, some research suggests the changes in the brain along with the dopamine release triggered by eating sweets and junk food are comparable to the changes caused by substances like cocaine or heroin.

"Sugar addiction" may not be a medical term, but quitting sugar cold turkey isn't a pleasant journey. For these reasons, it could be argued that sugary foods can have addictive properties, albeit not as intense as drug addiction. Likewise, while a heroin addiction can result in sudden death, the consequences of a high-sugar diet aren't as immediately dire. Still, the effects sugar-laden foods have on our biology and behavior tap into the addiction scope.

Now, we're not saying you'll go into a midnight sugar-need hysteria, searching through dumpsters or harassing people to get your sweet tooth fix. But, as we've seen in this study, regularly eating high-calorie and high-sugar foods causes significant changes in brain areas that regulate our behavior, mood and day-to-day choices, resulting in overeating and a variety of health concerns, including diabetes, obesity, chronic inflammation, dementia, heart disease and more.

What causes us to crave sugar?

When we crave sweet foods, it could be because we're still hungry. To our brains, salty foods and sweets are rewarding, quick energy sources, with one major drawback: they don't sustain us for very long. Often, food cravings arise because we haven't provided our bodies with enough food to fuel our energy needs. This can happen when the previous meal we ate was also high in sugar but low in protein, fiber and healthy fats. It also can happen when we aren't eating enough (aka on a restrictive diet). A morning cup of joe is not breakfast and a simple salad for lunch will not give your cells the nutrients they need to produce sustainable energy that helps you power through your day—it will only set you up to give in to your cravings.

That's why we tend to reach for high-calorie, fast-fuel sources rich in saturated fats and refined, processed sugars (ignoring satiety altogether). These foods provide us with a burst of short-lived energy that burns out within a few hours, resulting in low blood sugar levels and prompting us to want more—perpetuating blood sugar spike rollercoasters associated with hormone imbalances, insulin resistance, aging skin and more. And then the cycle repeats again.

Of course, other factors can influence what our bodies crave. Salty, fatty and sweet cravings kick in when we need a pick-me-up or when we're stressed, bored or lonely—we don't call it "comfort food" for nothing. Many people confuse thirst with craving sugar. And of course, it doesn't help that ripping open a bag of potato chips or a sugary snack is easier than preparing a high-fiber, high-protein meal, including healthy fats.

What should I eat when I crave sugar?

We'll be the first to tell you that it's ok to indulge your sugar cravings in moderation; satisfying our sweet tooth is a "pleasure" choice, not "healthy" one, but pleasure is very much a part of a life well-lived. The key is the "moderation" part: sometimes a bite or two of a brownie is more than enough to scratch the itch. We don't need to eat the entire thing; doing so will provide fleeting energy levels, trigger a cocktail of hormones and feel-good chemicals like dopamine and serotonin, but with hardly any nutrients, and it can impact your insulin response.

On the other hand, restricting ourselves from eating the foods we crave altogether can backfire, ultimately driving us to binge rather than enjoying that occasional salty or sweet-tasting treat.

Fortunately, there are nutrient-dense choices that will still quench the cravings without setting you up for yet another empty cookie bag. Here are a few ideas:

  • Fruits and dried fruits
  • Nuts and nut butter
  • Dark chocolate
  • Smoothies
  • Tahini-based treats
  • Sugar-free gum

Pro tip: Fight sugar cravings by adding nutritious protein sources to your snacks, such as chia seeds and Greek yogurt, and choose fiber-rich carbohydrates like quinoa, beets and sweet potatoes. If you're craving something salty or savory, fermented foods like sauerkraut and pickled onions are a great way to get more probiotics in your diet.

How do I stop my body from craving sweets?

The good news is that altering our food choices, and focusing on regularly eating balanced meals and plenty of fiber-rich and colorful veggies (eating sweets and junk food sporadically and in moderation) can help us rewire our brains into healthier-food-preferring habits—making healthy weight management a lot easier.

And dietary choices are only one piece of the puzzle. Here are eight ways you can help rewire your brain and reclaim control over those sneaky sugar cravings.

  1. Reduce your sugar intake:

    By reducing your sugar intake, you're rewiring your brain to choose more nutrient-rich foods. If this sounds daunting, start by creating an action plan that breaks down your goals into smaller, actionable steps. Write down what triggers your cravings; being aware of why you're seeking certain foods will give you a starting point. Decide what recipes you'll cook during the week (you can include desserts!) and base your shopping list on the ingredients you need.
  2. Seek guidance:

    Not sure where to start? A registered dietitian can be an excellent resource to build a balanced meal plan that covers all your nutritional needs, supporting healthy weight, balanced hormones, cognitive health and much beyond.
  3. Always read the label:

    Sticking to your shopping list is part of the puzzle; the other part requires some detective work. Take the time to read the label. Avoid processed foods, added sugars like corn syrup, artificial sweeteners and other ingredients that can impact blood sugar and hinder your wellness journey.
  4. Practice mindful food shopping:

    Never shop on an empty stomach; thanks to that mind-gut connection, if your digestive tract messages "I need food!" to your brain, you're more likely to give in and buy the family size bag of the food you're craving.
  5. Eat well-balanced meals:

    Your best bet is the Mediterranean diet, which has been linked to an array of whole-body health benefits because it incorporates plenty of leafy greens and colorful veggies (they are rich in polyphenols, health-promoting plant compounds), fruits, hearty carbohydrates and healthy fats like avocado, nuts, seeds and extra virgin olive oil. And of course, don't forget fatty fish like salmon and lean proteins like grass-fed meats or poultry.
  6. Find the crux of your craving:

    When that box of donuts beckons, consider this: are you really hungry, or are you thirsty? Or is something else triggering the urge to reach for another cupcake? It could be stress, boredom, or an imbalance of hormones like ghrelin and cortisol. Maybe it's your gut bacteria that's affecting your cravings. Addressing the core of the issue is the first step in managing cravings and bringing it into balance.
  7. Stay hydrated:

    Speaking of thirst, drinking enough water throughout the day can help manage sugar cravings. Add lemon and cucumber slices for a splash of nutrients and flavor.
  8. Get moving:

    A terrific way to manage blood sugar levels is to use your muscles after you eat something sugary. Your skeletal muscles, the ones you move voluntarily like your arms, legs and core, use up 80 percent of the glucose you consume. The best part? You don't have to go to the gym; any body movement counts—whether that's walking with your pooch, washing your car, cleaning your home, dancing or playing with your kids.

Summary: Sugar cravings and brain response

Let's recap: If you've ever felt like it's a (lost) battle trying to fight sugar cravings, especially after having a cookie or chocolate, don't feel bad: it's not your fault! According to a recent study published in Cell Metabolism, our everyday eating patterns are to blame, and not our willpower. The study found that regular consumption of foods high in fats and sugars directly impact brain areas associated with learning and motivation, rewiring the brain to crave sugars over nutrient-rich foods.

But a sugar-craving brain is not a lost cause! Changing our eating habits to include more high-fiber carbohydrates, lean protein and heart-healthy fats also rewires the brain's taste preferences and activity. Eating balanced meals on a regular basis is the key to unwavering willpower over sugar cravings.



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