One is lower in carbs, but a few simple swaps can help both dishes fit into your holiday meal.
Reviewed by Dietitian Jane Leverich, M.S., RDN
Key Points
- Green bean casserole is lower in carbs and sugar, making it more blood sugar–friendly than sweet potato casserole.
- Portion size and preparation tweaks, like swapping toppings, can make both casseroles fit a balanced plate.
- Pair casseroles with lean protein, fiber-rich veggies and a post-meal walk to help steady blood sugar levels.
Green bean casserole and sweet potato casserole often sit side by side on the holiday buffet, but if you have diabetes or prediabetes, you may have written them off. Between the crispy fried onions, cream soup, marshmallows and brown sugar, neither looks particularly blood sugar–friendly at first glance.
But just because you’re managing your blood sugar this holiday season doesn’t mean you have to skip your favorite sides. Dietitians break down how each dish may affect blood sugar, which one has the edge and how you can enjoy both while keeping your blood sugar steady.
How Green Bean Casserole Affects Blood Sugar
On their own, green beans are as blood sugar–friendly as a side dish can be. One cup of cooked green beans has just 9 grams of carbohydrates with 4 grams of fiber. Fiber helps slow digestion and can help moderate the rise in blood sugar after a meal. However, green beans are just one ingredient in the classic casserole.
“Green bean casserole’s carbohydrates mainly come from the fried onion topping and the flour in canned cream soup,” says Whitney Stuart, M.S., RDN, LD, CDCES.
While the exact nutrition of a green bean casserole depends on the recipe, a half-cup serving can have around 180 calories, 13 grams of carbohydrates, 1 gram of fiber and 13 grams of fat. The creamy sauce contributes some carbohydrates, while butter, cream and oil add fat. Fat doesn’t raise your blood sugar directly, but it can affect how quickly your body digests a meal. “The fat in the creamy sauce slows digestion, which can blunt the initial spike but may cause a more delayed, prolonged rise in glucose,” says Megan Byrd, RD.
Research suggests that higher-fat meals can lead to delayed and prolonged increases in blood sugar; however, the response depends on the meal and the individual. So while green bean casserole itself is low in carbs, eating it with other high-carb and high-fat foods could potentially cause your glucose levels to peak and stay elevated up to six hours after eating.
How Sweet Potato Casserole Affects Blood Sugar
Underneath the marshmallows and brown sugar, sweet potato casserole has some nutritional benefits, but it’s also higher in carbohydrates. Sweet potatoes themselves are a starchy vegetable that can raise blood sugar, but they’re also full of beneficial nutrients like fiber, vitamin A and antioxidants.
“Sweet potatoes are nutritious, but the added ingredients completely change the picture,” says Stuart. “Brown sugar, maple syrup and marshmallows significantly raise the sugar content, making sweet potato casserole more likely to spike blood sugar levels, especially if eaten first at the meal.”
The exact nutrition depends on your recipe, but a half-cup serving of sweet potato casserole can have around 170 calories, 32 grams of carbohydrates, 22 grams of sugar, 2 grams of fiber and 3 grams of fat before you add the marshmallow topping. Just 10 mini marshmallows on top add another 4 grams of sugar.
With that much sugar, you may see a larger spike in blood sugar after your meal, especially if the rest of your plate includes higher-carbohydrate foods like stuffing, rolls and other desserts.
Green Bean Casserole vs. Sweet Potato Casserole: Which Is Better for Your Blood Sugar?
“Green bean casserole would be the lower-carbohydrate and lower-sugar choice, which means it may have less of an impact on your post-meal blood sugar,” says Sara Wisehart, M.S., RD, LD, CDCES.
Sweet potato casserole contains more carbohydrates from both the sweet potatoes and added ingredients like brown sugar, maple syrup and marshmallows. That means it may have a greater impact on blood sugar, depending on the recipe and serving size.
But that doesn’t mean you have to pass on the sweet potato dish. “Both can fit into a holiday meal,” says Stuart. “Preparation and portion size are more important than the choice itself.”
How to Include Both in a Blood Sugar–Friendly Diet
Like one, the other or both? You’re in luck. You can enjoy both casseroles and keep your blood sugar steady with a few intentional tweaks.
- Start with protein and vegetables. Wisehart recommends starting with your lean protein and vegetables first, before digging into the sides. Research suggests that those with diabetes may get short-term benefits from eating carbohydrates after protein and vegetables.
- Trade marshmallows for a nutty crumble. If you’re in charge of the sweet potato casserole, Stuart recommends swapping the marshmallow topping for an oat-and-pecan crumble instead. You’ll cut a good portion of sugar while adding extra fiber and healthy fats.
- Rethink the crispy onions. If you’re making the green bean casserole this year, Byrd recommends rethinking how you approach the fried onions, recommending a lighter sprinkle or swapping them for a crunchy toasted almond topping instead.
- Keep your portions in mind. You don’t have to skip either casserole, but serving sizes matter. Try a smaller scoop of each alongside protein and vegetables rather than filling most of your plate with higher-carbohydrate sides.
- Don’t save up for the big meal. Skipping breakfast and lunch ahead of a big holiday dinner may seem like a good idea, but dietitians advise against it. “Eat on a regular schedule on holidays so you’re not starving when the main meal rolls around. This makes keeping your portions in check and balancing your plate much easier,” says Wisehart.
- Go for a post-dinner walk. Instead of crashing on the couch after your holiday meal, get up and walk around the block. Even a 10-minute walk after eating can help reduce post-meal blood sugar, blunting a spike before it happens.
Our Expert Take
Green bean casserole has an edge over sweet potato casserole when it comes to your blood sugar. With fiber-rich green beans and only a small amount of carbohydrates from the cream of mushroom soup and crispy fried onions, this dish is unlikely to cause a blood sugar spike on its own. Sweet potato casserole, on the other hand, has more added sugars from brown sugar, maple syrup and marshmallows, combined with already-starchy sweet potatoes. Even so, both can fit on your holiday plate if you watch portions and pair them with lean protein and fiber-rich vegetables.