How many carbs are in oatmeal?
One cup of cooked oatmeal has about 28g of carbohydrate and 24g of net carbs. Plain oats cooked in water have no added sugar. Instant flavored packets add significantly more.
Carbs by portion
| Portion | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| 1 cup cooked (234g) | 28.1g | 4.0g | 24.1g |
| 1 tbsp (14g) | 1.8g | 0.2g | 1.5g |
| 1 cup (175g) | 21.0g | 3.0g | 18.0g |
| 100 grams | 12.0g | 1.7g | 10.3g |
Net carbs
One cup of cooked oatmeal has about 24g of net carbs, which is total carbs (28g) minus fiber (4g). Oats contain beta-glucan, a soluble fiber that forms a gel in the gut and slows the absorption of glucose. See the net carbs guide.
Glycemic index of oatmeal
The glycemic index of oatmeal is about 55. Rolled oats and steel-cut oats have a GI in the low-to-moderate range, largely because of their beta-glucan content. Instant oats, which are more finely processed, have a higher GI closer to 79. Steel-cut oats sit lowest at around 42.
For diabetes
Plain cooked oatmeal has a GI of about 55, which is moderate. One cup has 28g of carbs, so it is still a real carb load, but the beta-glucan fiber slows absorption and tends to produce a flatter glucose curve than an equivalent amount of white bread or white rice. Flavored instant oatmeal packets often contain 30 to 40g of carbs per packet with added sugar. Steel-cut oats produce the lowest and slowest glucose rise of any oat variety. See the diabetes carb-counting guide.
Keto and low carb
One cup of cooked oatmeal has about 24g of net carbs, which fills most or all of a strict keto day's budget. Oatmeal does not fit keto. Some people make a low-carb oat-free 'noatmeal' with hemp hearts, chia seeds, and flaxseed.
Good to know
The type of oats changes the glycemic impact significantly. Instant oats are pre-cooked and rolled very thin, making them digest quickly with a GI around 79. Old-fashioned rolled oats sit around 55. Steel-cut oats, which are the least processed, have a GI around 42. All three types have similar total carb and fiber content per dry weight. Toppings do most of the damage: a tablespoon of maple syrup adds 13g of carbs, and brown sugar adds similar amounts.
Full nutrition (per 100g)
- Calories: 71.0 kcal
- Carbohydrate: 12.0g
- Fiber: 1.7g
- Sugars: 0.27g
- Protein: 2.54g
- Fat: 1.52g
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Get the appFrequently asked questions
How many carbs are in oatmeal?
One cup of cooked plain oatmeal (234g) has about 28g of carbohydrate. A half-cup serving has about 14g of carbs.
How many net carbs are in oatmeal?
One cup of cooked oatmeal has about 24g of net carbs, which is total carbs (28g) minus about 4g of fiber.
What is the glycemic index of oatmeal?
Rolled oats have a GI of about 55. Steel-cut oats are lower at about 42. Instant oatmeal is higher at about 79.
Is oatmeal OK for diabetics?
Yes, in a measured portion. One cup of plain rolled oats has 28g of carbs and a moderate GI. Steel-cut oats produce the slowest glucose rise. Avoid flavored instant packets, which add significant sugar.
Is oatmeal keto?
No. One cup has about 24g of net carbs, filling most of a strict keto day's budget.