What are the macros for 100g of oats?

January 5, 2026 •

3 min read

According to the USDA, a standard 100g serving of dry rolled oats contains approximately 379 calories, making it a nutrient-dense and energy-rich whole grain. This versatile food is a powerhouse of nutrition, and understanding what are the macros for 100g of oats is key to incorporating them effectively into a healthy diet.

Quick Summary

Dry, rolled oats offer a balanced macronutrient profile, including complex carbohydrates, ample protein, and healthy fats. Their high fiber content, particularly beta-glucan, is a key component that provides sustained energy and contributes to overall health.

Key Points

Carbohydrates Dominate: A 100g serving of dry oats contains approximately 68 grams of complex carbohydrates, providing sustained energy.
High in Fiber: With about 10-12 grams of dietary fiber, oats are excellent for digestive health and cholesterol management.
Significant Protein Source: Oats offer around 13 grams of protein per 100g, a high amount for a grain, though it is not a 'complete' protein on its own.
Contains Healthy Fats: The 6.5 grams of fat in oats are mostly heart-healthy unsaturated fatty acids.
Packed with Micronutrients: Oats are also a rich source of vitamins and minerals like manganese, phosphorus, and iron.
Supports Satiety: The high fiber and protein content contribute to a feeling of fullness, which is beneficial for weight management.
Glycemic Benefits: The beta-glucan fiber helps regulate blood sugar levels, making oats a good choice for diabetics.

A 100g serving of dry, uncooked oats is a nutritional powerhouse, providing a balanced profile of macronutrients essential for energy and health. While specific figures can vary slightly depending on the type of oat and testing methodology, the following values represent a typical nutritional breakdown.

The Macronutrient Profile for 100g of Oats

Carbohydrates: The Primary Energy Source

Carbohydrates are the most abundant macronutrient in oats, providing the body with its primary source of fuel. For a 100g serving of dry rolled oats, you can expect approximately 68 grams of carbohydrates. A significant portion of this is a unique type of fiber called beta-glucan, which is responsible for many of oats' health benefits. The carbohydrates in oats are complex, meaning they are digested slowly, leading to a gradual release of glucose into the bloodstream. This sustained energy release helps prevent the sharp spikes and crashes in blood sugar often associated with simple carbohydrates.

Key carbohydrate components include:

Dietary Fiber: A notable 10-12 grams of fiber are packed into 100g of oats. Beta-glucan is a soluble fiber known for its cholesterol-lowering effects and its ability to promote a feeling of fullness.
Resistant Starch: Oats contain resistant starch, which functions like fiber by escaping digestion in the small intestine. This feeds beneficial gut bacteria, contributing to better digestive health.

Protein: A High-Quality Plant-Based Source

Oats are surprisingly rich in protein compared to many other grains, offering approximately 13 grams of protein per 100g serving. This makes them an excellent option for vegetarians, vegans, and anyone looking to increase their plant-based protein intake. The primary protein in oats is avenalin, which has a moderate profile of essential amino acids, though it is slightly deficient in lysine. To form a complete protein, oats can be easily paired with lysine-rich foods like legumes or nuts.

Fat: Mostly Healthy Unsaturated Fats

Contrary to common belief, oats are not fat-free, though they are low in fat overall. A 100g portion contains around 6.5 grams of fat. The majority of this fat consists of healthy unsaturated fatty acids, including monounsaturated and polyunsaturated fats. These fats are vital for cell function and overall cardiovascular health. The natural presence of antioxidants in oats helps to maintain the stability of these fats, preventing rancidity.

Comparison of Oat Varieties

While the core macronutrient values remain similar, processing methods can slightly alter the nutritional profile and, more importantly, the glycemic impact of different types of oats. Whole oats and steel-cut oats, for example, take longer to digest due to their structure compared to rolled or instant oats.


Oat Type	Approx. Carbs (per 100g dry)	Approx. Protein (per 100g dry)	Approx. Fat (per 100g dry)	Processing Level
Steel-Cut Oats	68g	13g	6.5g	Minimally processed; whole groats chopped into pieces
Rolled Oats	68g	13g	6.5g	Steamed and flattened into flakes
Instant Oats	73g	13g	3g	Heavily processed, pre-cooked, and rolled thin

The Micronutrient Advantage

Beyond the macros, a 100g serving of oats provides a wealth of essential vitamins and minerals, supporting various bodily functions. These include:

Manganese: Crucial for growth, development, and metabolism.
Phosphorus: Supports bone health and tissue maintenance.
Magnesium: Important for a multitude of biological processes, including muscle function and energy production.
Iron: A key component of hemoglobin, which transports oxygen throughout the body.
B Vitamins: Includes thiamine (B1) and pantothenic acid (B5), which are essential for energy metabolism.

Conclusion: A Complete and Balanced Whole Grain

In summary, the macros for 100g of oats offer a comprehensive and balanced nutritional profile. With a high content of complex carbohydrates for sustained energy, a commendable amount of plant-based protein for muscle support, and healthy unsaturated fats, oats are an exceptional food choice. Their rich dietary fiber, particularly beta-glucan, sets them apart as a valuable ally for managing weight, stabilizing blood sugar, and improving heart health. By understanding their macros and benefits, you can make informed decisions to incorporate this powerhouse grain into your daily nutrition plan for long-term well-being.

For additional nutritional details and information on preparing oats, the USDA provides an extensive food database.

Frequently Asked Questions

Yes, oats are an excellent food for weight loss. Their high fiber and protein content promote satiety and can help reduce overall calorie intake by making you feel fuller for longer.

No, oat protein is not considered a complete protein because it is low in the essential amino acid lysine. However, its overall amino acid profile is strong for a plant-based source and can be complemented by pairing it with lysine-rich foods like legumes or nuts.

Beta-glucan is a type of soluble fiber found in oats. It forms a gel-like substance in the gut, which helps lower LDL ('bad') cholesterol, regulates blood sugar levels, and supports a healthy gut microbiome.

While the core macronutrient values are similar across different types of oats (steel-cut, rolled, instant), their processing level affects how the body digests them. Less processed varieties like steel-cut oats have a lower glycemic index, leading to a slower energy release.

Pure, certified gluten-free oats are generally considered safe for most people with celiac disease. However, cross-contamination with wheat can occur during processing, so it is crucial to choose only products that are certified gluten-free.

Based on USDA data, 100g of dry rolled oats contains approximately 379 calories.

Yes, eating oats daily as part of a balanced diet can be very beneficial. They offer sustained energy, are rich in fiber, vitamins, and minerals, and have been linked to improved heart health, blood sugar control, and weight management.