Green beans are not high in carbs. A one-cup serving (about 100 grams) contains just 7 grams of total carbohydrates, with 3 grams of that coming from fiber. That puts the net carb count at roughly 4 grams per cup, making green beans one of the lowest-carb vegetables you can eat.
How Green Beans Compare to Other Beans
The name “green beans” is a bit misleading. Unlike pinto beans, black beans, and kidney beans, green beans are picked and eaten while the pod is still immature, before the seeds inside have a chance to develop starch. This makes them nutritionally closer to vegetables like broccoli or zucchini than to the dried beans you’d find in a can of chili.
The American Diabetes Association classifies green beans as a non-starchy vegetable, placing them in the same category as peppers, spinach, and tomatoes. Most cooked legumes deliver 20 to 25 grams of net carbs per half-cup. A half-cup of green beans (about 60 grams) contains only 2 grams of net carbs. That’s a tenfold difference.
Net Carbs and Why They Matter
Total carbs and net carbs tell different stories. Net carbs subtract fiber from the total because fiber passes through your digestive system without raising blood sugar. Green beans contain a meaningful amount of fiber relative to their size: roughly 1.4 grams of soluble fiber and 2.9 grams of insoluble fiber per 100-gram serving, based on USDA analysis. Soluble fiber slows the absorption of sugar into your bloodstream, while insoluble fiber supports digestive regularity.
That fiber content is part of why green beans have such a gentle effect on blood sugar. Their glycemic index sits at about 32, which is considered low (anything under 55 qualifies). More telling is the glycemic load, which accounts for a realistic serving size. Green beans score a 1 on glycemic load, essentially the lowest possible impact a carb-containing food can have.
Green Beans on a Keto Diet
Most people following a ketogenic diet aim for 25 grams or fewer of net carbs per day. At 2 grams of net carbs per half-cup serving, green beans fit comfortably within that budget. Healthline identifies green beans as one of only two bean varieties that work on a keto diet (the other being black soybeans).
You could eat two full cups of green beans and still use up fewer than 10 grams of your daily net carb allowance. That’s a generous amount of food for very few carbs, which makes green beans useful for adding volume and crunch to keto meals without worrying about the count.
What Else You Get From Green Beans
Beyond low carbs, green beans deliver a solid nutritional return. A cup of cooked green beans provides about 20 micrograms of vitamin K, which plays a key role in blood clotting and bone health. They also supply vitamin C, folate, and small amounts of minerals like manganese and potassium. All of this comes in a package of roughly 31 calories per cup.
Green beans do contain lectins, proteins found in all plants but concentrated in legumes. In large amounts, lectins can cause digestive discomfort. The good news: cooking with heat and water (boiling, steaming, stir-frying) inactivates most lectins. Canned green beans are already fully cooked and low in lectins. The only real concern is eating raw or significantly undercooked beans, which most people don’t do anyway.
Fresh, Frozen, and Canned Differences
The carb content stays roughly the same whether you buy green beans fresh, frozen, or canned. Frozen green beans are typically blanched before packaging, which preserves nutrients without changing the macronutrient profile. Canned green beans can be higher in sodium depending on the brand, but the carb count remains comparable. If you’re watching sodium, look for “no salt added” versions or rinse them before cooking.
Preparation method matters more for what you add than for what’s already in the bean. Sautéing in butter or olive oil adds fat calories but no carbs. Tossing green beans with a sweet glaze or teriyaki sauce, on the other hand, can add several grams of sugar per serving. The beans themselves stay reliably low-carb regardless of how you cook them.