Sure, you might know that a donut or a slice or two of deep-dish pizza might not be the healthiest food to put in your mouth—and is bound to be pretty high on the glycemic index in terms of elevating your blood sugar—but it’s not just these blatant offenders that can make your levels go haywire.
It turns out there are several “healthy” foods, like whole wheat bread, that are super high on the glycemic index (GI), too. What’s the glycemic index? It’s a useful tool for evaluating which food among similar options is the best one to put on your plate, says Suzanne Dixon, registered dietitian with The Mesothelioma Center in Orlando, Florida.
Yet it can be misleading, as some of these healthier foods are just as high as candy bars! Seems odd, right? Well, it’s true.
Grains are often guilty of just that. Even whole wheat bread scores a 74, compared to white bread at 75, and a strawberry cupcake at 73!
To be fair, many non-grain items have a high GI too, like carrots and watermelon, but they won’t have such an effect on blood sugar, as the individual carb count per typical serving is generally low and they are mostly water-based and fibrous, says Dixon.
“Carrots are mostly water and fiber, so when eaten in typical quantities, they have very little effect on blood sugar levels,” she says. “The same is true for watermelon. It has a high GI of 80. But watermelon is mostly water. There aren't a lot of carbs in a serving of watermelon,” she says.
And sure—complex grains like whole wheat and bran are packed with nutrition and can be good for you—but they do also raise blood sugar and might contribute to inflammation in some people. So, if you are trying to eat lower-GI foods, you might want to think twice before overindulging in that “good morning muffin” and swapping for eggs or plain Greek yogurt instead.
Here are a few surprising foods that are super high on the index, so don’t think they won’t elevate your blood sugar levels to some extent!
Cake Donut GI = 76 vs. Barley Wheat Bread GI = 74
That’s right, having barley wheat bread can be just as hefty in GI as a cake donut from your bakery. Of course, barley wheat has more bang for your buck, with more fiber, vitamins, minerals, and phytonutrients, says Dixon. Yet if you're going based off GI for diet, you’ll want to be wary of those slices of bread. They’ll add up!
Vanilla Wafers GI = 77 vs. Grape-Nuts Cereal = 75
Grape-Nuts seems likes a healthy cereal choice, but first off, it’s hard to stop eating cereal, and those portion sizes for what should really go into your bowl with milk are tiny. Plus, many cereals still have sugars, and the GI is similar to a vanilla wafer treat.
Cornflakes, muesli and instant oat porridge score even higher. You’re better off picking steel cut oatmeal, which has a lower GI of 42 (just watch how much sugar or honey you add), or cooking up some eggs instead.
Potato Chips GI = 56 vs. Rice Cracker GI = 87
When you're roaming the aisles of a health foods store, you might pick up some rice crackers—bland and seemingly better for you than other crunchy, salty snacks. But those crackly disks that taste like you're eating styrofoam? According to Harvard, those come in at a whopping 87, outdoing the infamous potato chip by a long shot.
Jellybeans GI = 80 vs. Broad Beans GI = 80
Broad beans have the same GI as jellybeans—shocking, right? Sure, broad beans are pretty nutritious, and with tons of fiber they won’t affect blood sugar as much, but it’s still worth keeping portion size in check and pairing with other protein-rich foods to prevent blood sugar fluctuations.
Table Sugar GI = 65 vs. Couscous = 65
When you’re digging into a serving of couscous, you might as well be eating a serving of table sugar! Yikes. Think of that the next time you’re plopping it on your plate next to chicken. Rice will shoot your blood sugar even higher—white rice comes in at 73, and even brown rice scores 67. It might be worth swapping out for some broccoli instead, or if you really want a starch, try basmati rice, which has a relatively modest GI of 52.
Angel Food Cake GI = 67 vs. Shredded Wheat Cereal = 67
That shredded wheat cereal for breakfast might as well be a slice of angel food cake if you’re trying to eat a low GI diet. (PS—that really means you don’t want the frosted wheat version!) Go grain-free in the morning with some better sources of protein, like turkey patties or a tofu scramble. If you do want a grain, a slice of rye bread will have a GI of 41, and you can add some nut butter or avocado on top.
Check out where your other favorite foods are ranked on the glycemic index by visiting trusted logs like this, this, and this! For snacks free of wheat, corn, rice, maltose, and other grain ingredients, click here.
Isadora Baum is a freelance writer, certified health coach, and author of 5-Minute Energy. She can't resist a good sample, a margarita, a new HIIT class, or an easy laugh. She writes for various magazines, such as Men's Health, Women's Health, SELF, LIVESTRONG, POPSUGAR, Allure, Health, Cooking Light, and more. Learn more about her on her website: isadorabaum.com.