How Many Carbs Are In A Cob Of Corn? | Carb Facts

Corn belongs to a small group of foods that nutrition writers love to debate. One camp calls it a starchy vegetable best saved for special occasions. The other points to its whole-grain status and fiber content. Both sides are working from the same numbers — they just interpret them differently.

So when you’re standing at a summer barbecue holding a buttered ear, the honest answer about corn cob carbs is that it depends on the cob’s size. For a standard medium ear, the count settles around 22 grams of carbohydrates, with a few grams of fiber bringing the net impact lower. Here’s what those numbers mean for your meal plan.

Where the Carb Count Comes From

A medium ear of sweet yellow corn measuring about 6.75 to 7.5 inches long delivers roughly 22 grams of total carbohydrates. Subtract the 2.5 grams of fiber the ear also provides, and you land at roughly 19 grams of net carbs — the amount your body actually digests and uses for energy.

The rest of the ear brings a modest nutritional package. That same cob supplies about 88 calories, 3.3 grams of protein, and just 1.4 grams of fat. It also contains around 6 grams of naturally occurring sugar, which is far less than what you’d find in a piece of fruit or a sweetened snack bar.

Most of the carbohydrate in corn comes from starch, which is simply a chain of glucose molecules your body breaks down during digestion. Because that starch is wrapped in a whole-grain matrix with fiber, the energy release tends to be more gradual than what you’d get from refined starches.

Why The “Starchy Vegetable” Label Isn’t the Whole Story

Corn’s reputation as a “bad carb” comes from its starch content, but the label overlooks the full picture. Here’s what else is going on inside that kernel:

• A whole grain: Unlike refined grains, corn contains the germ, endosperm, and bran intact — Harvard’s nutrition source classifies it as a whole grain.
• Resistant starch: Corn contains resistant starch, a type of fiber that resists digestion in the small intestine. Some research suggests this may help lower the glycemic response compared to fully digestible refined carbohydrates.
• Low glycemic index (52): Boiled corn scores a 52 on the glycemic index, placing it in the low-GI category. It releases glucose into the bloodstream more slowly than high-GI foods like white bread.
• Portion control built in: An ear of corn is a naturally portion-controlled package. You get one clear serving without the temptation to mindlessly scoop more from a bag or bowl.

The key takeaway is context. A single cob eaten alongside protein and fat behaves differently in your body than a bowl of corn flakes or a drink sweetened with corn syrup.

How Corn Compares to Other Common Carbs

Putting the 22 grams of carbs from a cob of corn next to other familiar starches gives you a helpful frame of reference. A medium ear sits firmly in the middle of the pack — lower than a baked potato, comparable to a half-cup of rice or a small sweet potato.

This comparison highlights that corn is a moderate source of carbohydrates — higher than non-starchy vegetables but comparable to or slightly lower than other whole-food starches. As the WebMD corn nutrition facts show, the vitamins and fiber it provides set it apart from nutritionally empty refined options.

Can Corn Fit Into a Keto or Low-Carb Diet?

If you’re following a strict keto diet that limits net carbs to 20 to 50 grams per day, one ear of corn uses up a large chunk of your allowance. Whether it fits depends on how you structure the rest of your day.

1. Strict keto is tight but possible: With 19 grams of net carbs, a cob can be included if it’s the only substantial source of carbs for the day. Many keto resources still recommend avoiding it due to limited room.
2. Low-carb diets (50–100g net carbs): Are more flexible. A single cob fits comfortably within the daily allowance without requiring major trade-offs elsewhere.
3. It’s not an empty carb: The 2.5 grams of fiber, along with vitamin C, magnesium, and potassium, adds nutritional value that plain rice or bread doesn’t offer.
4. Budget once, don’t double up: If you eat the cob, skip the potato or bread at the same meal so your carb intake stays balanced against your specific target.

For anyone on a lower-carb plan, the honest approach is to budget for those 19 grams of net carbs and enjoy the cob as a treat rather than a daily staple.

The Glycemic Response and Blood Sugar

The glycemic index of boiled corn is 52, which places it in the low-GI category. Foods at this level raise blood sugar more gradually than high-GI foods like white bread or sugary cereals. The fiber and resistant starch in the kernel help slow down how quickly your body breaks the starch into glucose.

Pairing corn with protein or healthy fat — think butter or grilled chicken — can blunt the blood sugar response even further. That’s why a single cob alongside a balanced meal tends to have a much gentler effect on glucose than the same amount of carbs from a sugary drink or refined snack.

Healthline’s review of diabetes and corn notes that people with diabetes can include corn in moderation. The corn glycemic index 52 is well-documented, and the food doesn’t spike blood sugar the way refined grains sometimes do, though portion size still deserves attention if insulin sensitivity is a concern.

The Bottom Line

A cob of corn delivers roughly 22 grams of carbohydrates and about 19 grams of net carbs, with fiber, protein, and micronutrients that refined starches lack. It’s a whole grain with a low glycemic index, and it can fit into most balanced diets — though strict keto requires careful planning to accommodate the count.

If you’re managing diabetes or counting carbohydrates closely, a registered dietitian can help you fit a medium cob into your specific daily targets without throwing off your blood sugar or your carb budget.