Calories in Oatmeal: Nutrition Facts & Serving Sizes
Per 1 slice (27g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
Oatmeal is one of the most reliable breakfast staples for anyone focused on performance and body composition. Per 100g of dry instant oatmeal, you get 269 calories, 8.4g protein, 48.5g carbs, and 4.4g fat, with 4g of fiber. A standard 1 oz serving (about 28g) comes in around 76 calories with 2.4g protein. Oatmeal is rich in complex carbs that digest slowly and provide sustained energy before workouts or through a busy morning. It contains 24.6mcg of selenium per 100g, a key antioxidant mineral. The beta-glucan fiber in oats supports satiety, helping you stay fuller longer on fewer calories. Oatmeal is easily customized with protein powder, nut butter, or fruit to hit your macro targets.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 slice (27g) | 72.6 | 2.3g | 13.1g | 1.2g | 1.1g |
| 1 oz (28g) | 76.4 | 2.4g | 13.8g | 1.2g | 1.1g |
| 100g | 269 | 8.4g | 48.5g | 4.4g | 4g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 269 | 13% |
| Protein | 8.4g | 17% |
| Total Fat | 4.4g | 6% |
| Saturated Fat | 0.7g | 4% |
| Total Carbohydrates | 48.5g | 18% |
| Dietary Fiber | 4g | 14% |
| Sugars | 8.1g | 16% |
| Sodium | 447mg | 19% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 0.7g | 0% |
| Calcium | 66mg | 5% |
| Iron | 2.7mg | 15% |
| Potassium | 142mg | 3% |
| Vitamin A | 5mcg | 1% |
| Vitamin B6 | 0.1mg | 6% |
| Magnesium | 37mg | 9% |
| Phosphorus | 126mg | 10% |
| Zinc | 1mg | 9% |
| Selenium | 24.6mcg | 45% |
| Folate | 87mcg | 22% |
| Thiamin (B1) | 0.4mg | 33% |
| Riboflavin (B2) | 0.2mg | 15% |
| Niacin (B3) | 3.1mg | 19% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Oatmeal
Oatmeal is loaded with beta-glucan, a soluble fiber that slows digestion and keeps blood sugar stable. This means fewer energy crashes and better appetite control throughout the day, which is a major advantage when cutting calories. Research consistently shows beta-glucan helps reduce LDL cholesterol over time.
The iron content (2.7mg per 100g) supports red blood cell production and oxygen delivery to working muscles. Iron deficiency is a common cause of fatigue in active people, so oatmeal is a practical dietary source. Selenium (24.6mcg per 100g) acts as an antioxidant that protects cells from oxidative stress caused by intense training.
Oatmeal provides B vitamins including thiamin (0.4mg), riboflavin (0.2mg), and niacin (3.1mg), which all play roles in converting carbohydrates and fats into usable energy. This makes oatmeal particularly valuable as a pre-workout meal.
The folate content (87mcg per 100g) supports DNA synthesis and cell repair, which is important for recovery after heavy training. Add a scoop of protein powder to oatmeal to build out a complete pre or post-workout meal that hits both your carb and protein targets efficiently.
Dietary Considerations
Oatmeal is naturally vegan and dairy-free when made with water or plant milk. It is not gluten-free unless certified as such since oats are often processed near wheat. For weight loss, oatmeal is an excellent choice due to its high fiber content and slow-digesting carbs that promote fullness. It does not fit a strict keto diet since one 100g serving has 48.5g of carbs. For bulking or maintaining calories, oatmeal is easy to load up with calorie-dense toppings like nut butter, honey, or protein powder. Sodium content (447mg per 100g in instant) is worth noting if you are watching salt intake.
Daily Intake (100g)
100g of oatmeal provides 13% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in oatmeal?
Dry instant oatmeal has 269 calories per 100g. A standard 1 oz serving (about 28g) is roughly 76 calories. Cooked oatmeal made with water is lower in calories per cup since the oats absorb water and expand in volume.
Is oatmeal good for weight loss?
Yes, oatmeal is one of the best breakfast options for weight loss. Its high fiber content, especially beta-glucan, promotes fullness and helps reduce overall calorie intake throughout the day. Stick to plain oatmeal and watch portion sizes to keep calories in check.
How much protein is in oatmeal?
Oatmeal contains 8.4g of protein per 100g dry. A standard 28g serving provides about 2.4g of protein. To increase the protein content, add a scoop of protein powder, Greek yogurt, or peanut butter to your bowl.
Is oatmeal good before a workout?
Yes, oatmeal is an excellent pre-workout meal. The complex carbs digest slowly and provide a steady stream of energy without a blood sugar spike. Eat it 1-2 hours before training for best results.
Is oatmeal gluten-free?
Oats themselves do not contain gluten, but most oatmeal is processed in facilities that also handle wheat. If you have celiac disease or gluten sensitivity, look specifically for oatmeal labeled certified gluten-free.
What can I add to oatmeal to increase protein?
Great options include protein powder (20-25g protein per scoop), Greek yogurt (10g per 100g), peanut butter (8g per 2 tbsp), or egg whites stirred in while cooking. These additions let you turn a basic bowl of oatmeal into a high-protein meal.
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