By Melissa Schuster MS RDN CDN IFNCP, owner of Schuster Nutrition, PLLC
Blood sugar balance is at the heart of energy, metabolism, and long-term disease prevention. But, the topic of sugar can be confusing. Between added sugars, natural sugars, carbs, and everything in between, it’s hard to know what actually matters for your energy, weight, and long-term health. As a registered dietitian, I work with clients every day who feel like they’re doing most things right—but still experience fatigue, cravings, and weight gain. One of the most common culprits? Blood sugar swings.
This blog is your guide to understanding how sugar works in the body, how to manage blood sugar spikes without obsessing over every bite, and what it looks like to eat in a more balanced way, without cutting out carbs or fearing fruit.
What Is Sugar, Really?
Sugar is a type of carbohydrate, and all carbs (whether from bread, fruit, pasta, or cookies) are broken down into sugar molecules during digestion. These fall into two categories:
- Monosaccharides: single sugar molecules like glucose, fructose, and galactose.
- Disaccharides: combinations of two sugars, like sucrose (table sugar = glucose + fructose) and lactose (milk sugar = glucose + galactose).
Digestion starts in the mouth (thanks to salivary amylase), continues in the stomach and small intestine, and ultimately breaks carbs down into glucose, fructose, or galactose. These enter your bloodstream as blood sugar. From there, your pancreas produces insulin to help move that sugar into your cells for energy or storage.
The Blood Sugar Response and Insulin’s Role
Once glucose enters the bloodstream, the pancreas releases insulin to shuttle glucose into the body’s cells to be used for energy or stored for later use. When we eat foods high in sugar—particularly without any fat, fiber, or protein—blood glucose levels spike rapidly. That spike requires a larger insulin release to bring blood sugar back down.
So, for example… if you eat something high in sugar, like a pastry or soda, on an empty stomach, your blood sugar spikes quickly. That triggers a big insulin response to bring it back down. These rollercoaster spikes and crashes can leave you feeling tired, cranky, and craving more sugar.
Over time, repeated glucose spikes and high insulin demands can lead to insulin resistance. This means your cells don’t respond as well to insulin, forcing your pancreas to work overtime. This can contribute to weight gain, metabolic syndrome, and eventually type 2 diabetes.
Natural vs. Added Sugars (and Why It Matters)
Natural sugars are those found in whole foods like fruit and dairy. Importantly, these sugars come packaged with fiber, water, vitamins, and minerals that slow digestion and moderate the blood sugar response. For example:
- An apple contains fructose, but also fiber and antioxidants.
- Greek yogurt contains lactose, but also protein and probiotics.
As a dietitian, it’s important to share the PSA: fruit is not the enemy. Yes, fruit contains sugar (mainly fructose), but it also contains fiber (and water, vitamins, antioxidants) that slow the sugar rush. That means your body processes it more gently than, say, juice or candy.
That said, how you eat fruit matters. Here’s what I recommend:
- Pair fruit with protein or healthy fats (like berries + Greek yogurt, banana + peanut butter, or apple + cheese) to keep blood sugar steady.
- Be mindful of portions. Yes, fruit is healthy—but 3 cups of watermelon in one sitting is a lot of sugar all at once, even with the fiber. Too much of a good thing can still cause a blood sugar spike.
Added sugars, the kind that sneak into flavored yogurts, dressings, sauces, granola bars, and more, are a different story. These are sugars that are added during processing or cooking and often come without the fiber, protein, or nutrients that slow digestion. Common names include:
- High fructose corn syrup, cane juice, agave, brown rice syrup, dextrose, maltose, fruit juice concentrate.
These sugars hit your bloodstream quickly and are more likely to cause blood sugar spikes. The American Heart Association recommends keeping added sugars to no more than 25 grams (6 teaspoons) per day for women and 36 grams for men—and it adds up fast.
Real-Life Tips to Balance Blood Sugar
You don’t need to avoid carbs or sugar completely. It’s about combining foods wisely and being a little more intentional. Here’s what I recommend to my clients:
- Don’t eat carbs naked: Pair a carb with a protein, fat, or fiber. Think toast + eggs, fruit + nuts, crackers + cheese.
- Build your meals around balance: Include something from each category—protein, fat, fiber-rich carb—to slow digestion and keep blood sugar steady.
- Read labels, but don’t obsess: Start by checking for added sugars in foods you eat often. A little awareness goes a long way.
- Watch your morning routine: A sugary coffee + nothing else is a recipe for a 10 a.m. crash. Try adding protein (like eggs, yogurt, or a smoothie with protein powder) to your breakfast. You can download my free breakfast ebook with 10 easy high-protein recipes here.
What About Sweeteners?
Some people turn to artificial or zero-calorie sweeteners—like Splenda, stevia, or monk fruit—as a way to cut sugar without missing the taste. While these don’t raise blood sugar directly, research is still catching up on how they may affect metabolism, insulin sensitivity, and gut health.
One tip? Instead of swapping sugar for sweeteners, try to reduce your overall preference for sweetness gradually:
- Switch from Diet Coke to Spindrift or seltzer with lime.
- Cut back on Splenda in your coffee and add a splash of whole milk or a sprinkle of cinnamon for flavor.
- Use mashed banana or applesauce in baking to sweeten without the added sugar naturally.
It’s not about perfection—it’s about slowly retraining your palate so you don’t need everything to taste ultra-sweet.
When to Seek Support from a Dietitian
If you’re:
- Tired all the time, even when you sleep well
- Gaining weight despite eating “clean”
- Struggling with PCOS, insulin resistance, or energy crashes
- Feeling out of control around sugar or snacks
…you don’t have to figure it out on your own. Nutrition isn’t one-size-fits-all, and working with a registered dietitian can help you take the guesswork out of what your body needs. We’ll examine your patterns, help you understand your blood sugar response, and develop a personalized plan that suits your lifestyle.
Want more support? I work 1:1 with clients to create blood sugar-friendly meals, manage cravings, and feel better in their bodies—without dieting. You can learn more here or schedule a free clarity call here.
DISCLAIMER: The information contained in this post is not, and should not be construed as, medical advice. It is provided for informational purposes only. Each individual’s situation, nutritional needs and medical situation are different, and the information contained in this post may not be appropriate for your personal situation. Always check with your own physician or medical professional before implementing any change to your lifestyle, food intake, exercise regimen or medical treatment.
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