Starchy vegetables like potatoes, corn, peas, and winter squash pack significantly more carbohydrates than their non-starchy counterparts. A half-cup of cooked starchy vegetables typically contains around 15 grams of carbohydrate, while the same amount of non-starchy vegetables like broccoli or spinach has roughly 5 grams. That threefold difference matters if you’re watching your blood sugar, counting carbs, or following a low-carb diet.
Potatoes and Root Vegetables
Potatoes are the most carb-dense vegetable most people eat regularly. A 100-gram serving of baked white potato (about a quarter of a large potato) contains around 21 grams of carbohydrate, with about 2 grams of fiber. Over 95% of a potato’s dry weight comes from carbohydrates, which is why potatoes land in the moderate glycemic index range (56 to 69) alongside white rice and couscous.
Sweet potatoes are slightly lower, with about 17.3 grams of carbohydrate per 100 grams raw. They also contain more sugar (about 6 grams per serving) than white potatoes, which gives them their characteristic sweetness. True yams, which are a completely different plant despite the name confusion at grocery stores, are actually higher in carbs than either option at roughly 28 grams per 100 grams raw, though they contain almost no sugar.
Other root vegetables that fall on the higher-carb end include parsnips and cassava. Cassava is particularly dense: a serving of just one-third cup delivers 15 grams of carbohydrate. Parsnips hit that same 15-gram mark at a half cup. Carrots and beets, while technically root vegetables, are classified as non-starchy and contain considerably less carbohydrate per serving.
Corn
Corn is botanically a grain, but it shows up on most people’s plates as a vegetable. One large raw ear of sweet corn contains about 27 grams of carbohydrate, nearly 4 grams of fiber, and close to 5 grams of sugar. That single ear has roughly the same carb load as a baked potato. Harvard Health ranks corn in the moderate glycemic index category and suggests swapping it for peas or leafy greens if you’re trying to lower your glycemic intake.
A half cup of cooked corn kernels delivers 15 grams of carbohydrate, which is the standard “one carb choice” used in diabetes meal planning. Mixed vegetables that include corn or peas also count as starchy, even when they contain green beans or carrots. A full cup of those frozen mixed-vegetable blends hits the same 15-gram carb threshold because the corn and peas drive up the total.
Green Peas and Legumes
Green peas often surprise people. They look like a simple green vegetable, but a half cup of cooked green peas contains 15 grams of carbohydrate, placing them firmly in the starchy category. Black-eyed peas and split peas carry similar carb loads at a half-cup serving.
Beans and lentils push even higher. Just one-third cup of cooked black beans, kidney beans, chickpeas, navy beans, or pinto beans delivers 15 grams of carbohydrate. Lentils are the most concentrated of the group: a quarter cup of cooked lentils reaches that same 15-gram mark. These foods also provide substantial protein and fiber, which slows digestion and blunts blood sugar spikes, but the raw carbohydrate numbers are still high enough to matter for anyone tracking intake closely.
Winter Squash
Acorn squash, butternut squash, and other winter varieties contain more carbohydrate than most people expect from a vegetable. You need a full cup of cooked winter squash to hit 15 grams of carbohydrate, so they’re less carb-dense per bite than potatoes or corn. Butternut squash has almost half the carbohydrate of a sweet potato by weight, according to Harvard’s Nutrition Source. Calorie-wise, winter squash runs between 45 and 90 calories per cup cooked depending on the variety.
Despite their carb content, winter squash varieties have a low glycemic index and glycemic load. They contain polysaccharides, a type of indigestible fiber that helps prevent sharp blood sugar spikes after eating. This makes winter squash one of the more forgiving high-carb vegetables if blood sugar management is your concern.
Plantains and Other Tropical Starchy Vegetables
Plantains, cassava, and dasheen (taro) are staple carbohydrate sources in many cuisines around the world, and they’re among the most carb-dense vegetables available. Just one-third cup of cooked plantain, cassava, or dasheen contains 15 grams of carbohydrate. For comparison, you’d need a full cup of winter squash or a half cup of corn to reach the same amount. If you’re building a meal around one of these, treat it more like a serving of rice or bread than a side of vegetables.
How Cooking Changes the Equation
The way you prepare high-carb vegetables affects how your body processes the starch. Raw potatoes contain a form of resistant starch that your small intestine can’t fully break down. Cooking destroys that structure, making the starch highly digestible and raising its glycemic impact. But here’s the useful part: cooling cooked potatoes (or rice, or bread) causes the starch to partially re-crystallize into a new form called retrograded starch, which resists digestion again.
Cooling white rice at refrigerator temperature for 24 hours before reheating produced significantly more resistant starch and a measurably lower blood sugar response in healthy people compared to freshly cooked rice. The same effect applies to potatoes. Even reheating in a microwave after cooling preserves some of this resistant starch. So a cold potato salad or reheated leftover potatoes will raise your blood sugar less than a freshly baked potato, even though the total carbohydrate on a nutrition label stays the same.
Low-Carb Vegetables for Comparison
Non-starchy vegetables contain roughly 5 grams of carbohydrate per half cup cooked or per cup raw. This category includes broccoli, cauliflower, green beans, peppers, eggplant, mushrooms, onions, tomatoes, zucchini, and summer squash. Salad greens like lettuce, romaine, spinach, and arugula contain so little carbohydrate that they’re often counted as “free foods” in carb-counting systems.
If you’re trying to reduce carbs without giving up volume on your plate, swapping starchy vegetables for non-starchy ones is one of the simplest trades you can make. Replacing a cup of corn with a cup of roasted broccoli cuts roughly 10 grams of carbohydrate from the meal. Cauliflower mash instead of mashed potatoes, zucchini noodles instead of corn pasta, and riced cauliflower instead of peas in a stir-fry are all practical swaps that keep the plate full while pulling carbs down substantially.