Oatmeal nutrition facts: calories, protein and fiber
Quick answer: a standard serving of oatmeal is 1/2 cup of dry rolled oats (40 g), which has about 150 calories, 5 g protein, 27 g carbohydrate, 4 g fiber and 3 g fat. Cooked with water it makes about 1 cup. Oats are a whole grain, and their soluble fiber, beta-glucan, helps lower LDL cholesterol.
Oatmeal nutrition per serving
| Nutrient | 1/2 cup dry rolled oats (40 g) |
|---|---|
| Calories | about 150 |
| Protein | 5 g |
| Carbohydrate | 27 g |
| Fiber | 4 g |
| Of which beta-glucan | about 1.5-2 g |
| Fat | 3 g |
| Sugars | about 0.5 g |
| Iron | about 10% DV |
| Magnesium | about 13% DV |
Oats cooked in water have the same nutrients as the dry oats you started with. The water just dilutes them, which is why cooked oatmeal looks much lower in calories per 100 g. See the same effect with rice calories cooked vs uncooked.
Rolled vs steel-cut vs instant oats
| Type | How it is made | Cook time | Texture |
|---|---|---|---|
| Steel-cut | Whole groats chopped into pieces | 20-30 min | Chewy |
| Rolled (old-fashioned) | Groats steamed and flattened | 5 min | Soft, holds shape |
| Quick oats | Rolled thinner and cut smaller | 1-2 min | Softer |
| Instant | Precooked and dried, often flavored | Add hot water | Mushy |
Per gram, plain versions have almost identical nutrition. The difference is how fast they digest: steel-cut and rolled oats raise blood sugar more slowly than instant. Flavored instant packets can have 10 to 15 g of added sugar each.
Oats and cholesterol
Beta-glucan forms a gel in the gut that binds cholesterol-rich bile acids. The FDA allows a heart health claim for foods that provide at least 0.75 g of beta-glucan per serving, as part of a diet with 3 g of beta-glucan a day. That is about 1.5 cups of cooked oatmeal.
How to make oatmeal more filling
Oatmeal on its own is low in protein. To make it last until lunch:
- Cook it in milk instead of water (adds about 4 g protein per 1/2 cup milk)
- Stir in Greek yogurt or a scoop of protein powder
- Top with nuts, seeds or peanut butter
- Add fruit instead of sugar
For a no-cook option, try our overnight oats recipe.
Are oats gluten-free?
Oats do not contain gluten themselves, but they are often grown and processed alongside wheat. People with celiac disease should buy oats labeled certified gluten-free.
Frequently asked questions
How many calories in a cup of cooked oatmeal? About 150 to 165 calories when made with water from 1/2 cup dry oats.
Is oatmeal good for weight loss? It can help because fiber keeps you full, but toppings add calories quickly.
How much is a serving of oats? 1/2 cup dry rolled oats or 1/4 cup dry steel-cut oats, both about 40 g.
This article is general information, not medical advice.