When it comes to managing blood sugar, a healthy diet is crucial. And while there are plenty of blood sugar-stabilizing foods to add to your diet to help the cause, cutting out the worst culprits of blood sugar spikes is just as important. The unfortunate truth is that many popular foods, including those marketed as healthy or convenient, can be detrimental to your blood sugar levels due to added sugars, refined carbs, and a lack of fiber. Over time, these inflammatory ingredients can lead to insulin resistance, energy crashes, weight gain, and even chronic health issues.
To shed some light on a few of the worst offenders—including some that may surprise you—we gathered expert insight from dietitians and doctors. From breakfast cereal and granola to fruit juice and your go-to Starbucks order, find all of their warnings about the worst picks for your blood sugar below.
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1. Cereals
Cereal is a popular breakfast staple that can be found in almost everyone’s pantry. But many commercially available cereals can cause blood sugar spikes because of their high levels of refined carbohydrates and added sugars.
Even the ones marketed as "healthy" or "whole grain" can contain significant amounts of hidden sugar, which rapidly breaks down into glucose, leading to a quick increase in blood sugar levels.
"Cereals are often very high in sugar and low in fiber, which means they pass through your digestive system quickly. Fiber keeps you feeling fuller for longer, which helps control your food intake and prevent weight gain. It also causes slower digestion, which means a slower release of energy into your bloodstream throughout the day. Even brands like Special K and Life, which are heavily marketed as weight loss-friendly cereals, have the same low amount of fiber found in the common sugary brands like Frosted Flakes," Destini Moody, a registered dietitian and certified specialist in sports dietetics says.
2. Fruit Juice
Fruit juice may sound healthy, but believe it or not, many of them contain a lot of sugar with barely any fiber. Fruit juices are often concentrated sources of natural sugars, like fructose, which are quickly absorbed into the bloodstream. Contrary to whole fruit, these juices lack the fiber that helps slow down the absorption of sugar.
"Artificially flavored fruit juices with high amounts of added sugars are the worst for weight gain and blood sugar. These typically include things like fruit punch, lemonade, Hawaiian punch, high-c, and fruit cocktail juices. These fruit juices contain very little fruit, if any at all," says Jesse Feder, a personal trainer and registered dietitian.
3. Granola Bars
We're all busy, especially in the mornings! So as tempting as it is to load up on granola bars you can easily grab on your way out the door and eat on-the-go, a lot of options are unhealthy because of the hidden and high amounts of sugar.
"Many commercially available breakfast bars are high in sugars and low in fiber," cautions Dr. Rimas Geiga, MD, a registered dietitian nutritionist. "Look for bars with whole grains, nuts, and seeds, or make your own at home." This ensures you have control over the ingredients and can avoid excessive sugar.
4. Bagels
While certainly delicious, many bagels are dense and often large, meaning they contain high amounts of carbs in one serving. Without enough fiber or protein to slow down glucose absorption, eating a bagel can lead to a sharp blood sugar spike. This is especially true when paired with sugary and high-calorie spreads or consumed on its own without balancing proteins or fats.
"Refined carbohydrates like bagels lack fiber and can lead to rapid spikes and crashes in blood sugar. Opting for whole-grain or alternative flour options can provide sustained energy and aid in weight loss," Shana Abraham, a NASM-certified personal trainer and Precision Nutrition-certified nutrition coach reveals.
5. Sweetened Yogurts
Many sweetened yogurts are usually marketed in a way that makes you think they’re healthy for you. While yogurts like plain Greek yogurt have tons of benefits, it’s a different story with sweetened, processed ones. Sweetened yogurts often contain high amounts of added sugars, which are rapidly absorbed into the bloodstream. Like the other foods and drinks that are mentioned, these yogurts also lead to a quick increase in blood glucose levels.
"These days, you will notice that commercial yogurts are full of sugar and sweeteners with minimal protein content. Avoid regular yogurts that have no protein and only give you excess sugar," Juliana Tamayo, MS, RD, a registered dietitian and health expert at Fitness Clone, tells us. Instead, try high-fiber Greek yogurt topped with fruit.
6. Donuts
Donuts, with their enticing glazes and sugary toppings, are often a culprit when it comes to weight gain and inflammation, warns Lisa Richards, nutritionist and creator of the Candida Diet. She explains that cutting them out for a flatter belly may be a good idea: "Donuts have a high content of refined sugars, unhealthy fats, and processed ingredients. They are typically made with refined wheat flour and packed with added sugars, causing a rapid rise in blood glucose levels when consumed. This sudden spike in blood sugar triggers a corresponding surge in insulin to regulate sugar levels, which can be harmful to the body in the long term and lead to insulin resistance." Got it!
7. White Bread
"White loaf bread commonly used to make sandwiches is the worst form of bread to consume for many reasons, but especially its inflammatory effects," Richards warns. Refined carbs like those found in white bread have been stripped of practically all of their nutritional value.
As Richard explains, they "have undergone a refining process where the fiber and beneficial nutrients are removed and possibly replaced with synthetic versions." She notes that because of this, products like white bread "damage the gut by causing inflammation and feeding bad bacteria, leading to gut dysbiosis." Over time, that inflammation can also lead to weight gain. Another major factor here is the fact that eating white bread can lead to blood sugar spikes. The sugar content is especially bad when you consider the fact that the refined carbs lack nutritional value and offer virtually no fiber—so not only does white bread pack in the sugar, but it's also all for nothing, because it won't keep you full for very long. And that means you'll likely run into cravings and overeating later in the day.
Instead of subjecting your body to these effects, experts say you should go for healthier types of bread, like whole grain and sprouted options. You may be surprised by how much better you feel—and how much it helps you lose weight!
8. Sugary Condiments
Sugary condiments can be stealthy culprits in the battle against weight gain. Often overlooked, these sweet additions to our meals, such as ketchup, mustard, and high-sugar salad dressings, can pack a powerful punch of added sugars. Mary Sabat MS, RDN, LD says, "These condiments often contain high fructose corn syrup and added sugars, which can lead to inflammation when consumed in excess. They also add empty calories to meals, potentially contributing to weight gain."
Being mindful of the hidden sugars lurking in condiments and opting for healthier alternatives can be a major step in maintaining a balanced diet and achieving weight management goals.
9. Sugary Granola
Granola is often marketed as a health-conscious choice. However, just as with granola bars, it can sometimes hide a surprising amount of added sugars and unhealthy fats. While it's true that granola can be a good source of fiber and certain nutrients, particularly if made with whole grains, nuts, and seeds, many commercial varieties are heavily processed and loaded with sugars and oils.
"Granola is typically high in both added sugars and calories. The high sugar content can contribute to gut inflammation and unwanted abdominal fat. Granola is also quite dense in calories which can add to weight gain," Jesse Feder, a personal trainer & registered dietitian at myfoodallergyteam.com says.
Homemade granola is a good alternative!
10. Store-bought Cookies
Store-bought cookies, laden with refined sugars, unhealthy fats, and artificial additives, can contribute significantly to weight gain and inflammation. The high sugar content in these sweet treats not only leads to an increased calorie intake but also triggers insulin spikes, promoting fat storage.
Valeria Dolbel, founder of Beauty Diets, says cookies count as a "food category that contributes the most calories accounted for added sugar intake yet provide little to no nutritional value." She further adds, "Low fiber and highly refined grains increase the risk of weight gain and higher levels of belly fat," adding that your favorite cookie likely "causes belly fat due to highly processed ingredients such as butter, sugar, and refined flour."
11. Sugary Coffee Drinks
While a cup of coffee can be a morning savior, sugary versions like lattes and cappuccinos loaded with syrups and whipped cream are detrimental. "These drinks can pack a sugary punch, spiking blood sugar and promoting inflammation," says Dr. Krutika Nanavati, a registered nutritionist and dietitian.
High sugar intake has been linked to increased inflammatory markers. Additionally, these drinks often contain a high number of empty calories, which can contribute to weight gain and further exacerbate inflammation. Opting for black coffee or a simple espresso can be a much healthier way to enjoy your morning caffeine fix (and may even help you lose weight).
12. Sports Drinks
Designed for intense workouts, sports drinks are often consumed as morning beverages by many. However, they can come with their downsides. Dr. Nanavati warns, "They are loaded with sugar and electrolytes unnecessary for most people, potentially contributing to inflammation."
These drinks are formulated to replenish electrolytes lost during vigorous exercise, but for the average person, especially in the morning, they are unnecessary. The high sugar content can lead to a quick energy spike followed by a crash, making them a poor choice for a morning pick-me-up. Instead, stick to water or herbal teas to start your day.
