Calories in oats: dry and cooked, protein per 50 g, and blood sugar

By the Voltra team · Updated 6 October 2026

Calories per 100 g: dry and cooked

USDA FoodData Central. Dry means oats as they come out of the pack; USDA's record covers regular (rolled) and quick oats. Carbs include the fibre.

Some sites give 389 kcal and 16.9 g of protein per 100 g. That's a different USDA record, for oats supplied through its Food Distribution Program [3]. We use the regular and quick oats record because it has a matching cooked record [1][2]. USDA's newer analysis of rolled oats, from 2022, comes to about the same 379 kcal [4].

A cup, 50 g and other portions

Calculated from the values per 100 g above and USDA's weights [1][2][4]. 40 g is the US reference amount for a serving of oats [4].

Saudi Arabia's Healthy Food Palm counts half a cup of oats as one grain serving, and recommends 6 to 11 grain servings a day [11]. It doesn't say dry or cooked, and that matters: half a cup of dry oats is about 40 g and 153 kcal, and half a cup of cooked oats about 117 g and 83 kcal (calculated from USDA's cup weights) [1][2]. For bread, see our bread guide, with Saudi makers' labels.

Dry or cooked: the logging mistake

Cooking doesn't change the calories in your oats; it adds water. 100 g of dry oats has 379 kcal and 100 g of porridge 71, so a bowl of porridge weighs about five times as much as the dry oats in it (calculated: 379 divided by 71 is 5.3) [1][2]. 50 g of dry oats makes about 270 g of porridge cooked with water, depending on how much water you use (calculated).

• Weighing the cooked bowl and logging it as dry oats counts about five times too many calories: 270 g logged as dry is about 1,000 kcal instead of 190 (calculated).
• Weighing dry oats and logging them as cooked counts about five times too few: 50 g logged as cooked is about 36 kcal instead of 190 (calculated).

Weigh oats dry when you can: the dry weight stays the same however you cook them.

Oats with milk

Calculated by adding USDA's figures for dry oats and for milk with 3.25% fat or fat-free [1][5][6].

A tablespoon of honey (21 g) adds about 64 kcal (calculated) [7]. For fruit on top, see our banana guide.

Carb or protein?

Mostly carbohydrate. 100 g of dry oats has 67.7 g of carbohydrate, of which 10.1 g is fibre, and 13.2 g of protein: about five times as much carbohydrate as protein [1].

So oats on their own are a carbohydrate food with some protein. 50 g gives you 6.6 g of protein; cooking it in a cup of milk more than doubles that, to about 14 g (calculated) [1][5]. For your daily target, see how much protein you need a day.

Do oats raise blood sugar?

All oats raise blood sugar, since they're mostly starch [1]. How fast depends on the kind. The 2008 international tables of glycaemic index (GI), where glucose is 100, give these averages [8]:

Averages from several studies for each food, Table 1 [8]. The same paper calls 55 or less low and 70 or more high. Calories for rice are in our rice guide.

So rolled-oat porridge sits at the top of the low range, and instant oat porridge is as high as white bread [8].

Oats' soluble fibre, β-glucan, blunts the rise when it's added to a meal. A 2021 review of 103 single-meal comparisons in 538 people found that adding oat β-glucan, as a concentrate or as oat bran, to a carbohydrate meal cut the rise in blood sugar after the meal by 23% and its peak by 28%, against meals with the same carbohydrate [9]. The effect grew with the dose, held only for β-glucan of high molecular weight (above 300 kg/mol), and was similar in people with and without diabetes [9].

Whether after-meal rises matter if you don't have diabetes is covered in our guide to blood sugar spikes after eating.

Oats and cholesterol

A 2016 review of 58 trials (3,974 people) lasting at least 3 weeks found that diets with oat β-glucan, at a median of 3.5 g a day, lowered LDL ("bad") cholesterol by 0.19 mmol/L, about 7 mg/dL (calculated), compared with control diets [10]. Results varied a lot between trials [10].

USDA's analysis of rolled oats found 7.52 g of β-glucan per 100 g [4], so 3.5 g is in about 47 g of dry rolled oats (calculated).

Do oats make you gain weight?

Only through their calories, like any food. What changes the number is the portion and what goes in the bowl: 50 g of dry oats is about 190 kcal cooked in water, about 338 with a cup of full-fat milk, and a tablespoon of honey adds about 64 (calculated) [1][5][7]. Weigh the dry oats once or twice to see what your usual scoop holds. For your daily total, see how many calories you need a day.

How to log it in Voltra

1. Oats you weighed dry: on the Eat tab, tap Search, type "oats" and choose Oats, rolled (dry). Half a cup is set at 40 g; change the grams to what you weighed.
2. Plain porridge you weighed after cooking: tap Search and type "oatmeal cooked". One cup is set at 240 g.
3. Oats with milk, fruit or honey: tap Scan a meal and photograph the bowl, or tap Describe and type it with the dry weight, for example "50 g oats, 1 cup full-fat milk, 1 tablespoon honey". Check the grams, then tap Log.

Frequently asked

Sources

1. USDA FoodData Central. Cereals, oats, regular and quick, not fortified, dry (FDC 173904). Weights: 1 cup 81 g, 0.33 cup 27 g.
2. USDA FoodData Central. Cereals, oats, regular and quick, unenriched, cooked with water (includes boiling and microwaving), without salt (FDC 173905). Weights: 1 cup 234 g, 0.75 cup 175 g.
3. USDA FoodData Central. Oats (Includes foods for USDA's Food Distribution Program) (FDC 169705). 389 kcal and 16.9 g of protein per 100 g.
4. USDA FoodData Central, Foundation Foods (2022). Oats, whole grain, rolled, old fashioned (FDC 2346396). 379 kcal per 100 g; β-glucan 7.52 g per 100 g, the mean of 8 samples (6.07 to 8.88 g); reference amount 40 g.
5. USDA FoodData Central. Milk, whole, 3.25% milkfat, with added vitamin D (FDC 171265). Weight: 1 cup 244 g.
6. USDA FoodData Central. Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim) (FDC 171269). Weight: 1 cup 245 g.
7. USDA FoodData Central. Honey (FDC 169640). Weight: 1 tablespoon 21 g.
8. Atkinson FS, Foster-Powell K, Brand-Miller JC (2008). International tables of glycemic index and glycemic load values: 2008. Diabetes Care 31(12):2281–2283. Table 1.
9. Zurbau A, Noronha JC, Khan TA, Sievenpiper JL, Wolever TMS (2021). The effect of oat β-glucan on postprandial blood glucose and insulin responses: a systematic review and meta-analysis. Eur J Clin Nutr 75(11):1540–1554. Abstract. Two authors work for INQUIS Clinical Research, a contract research company; another declares in-kind food donations for a trial from companies including Quaker.
10. Ho HV, Sievenpiper JL, Zurbau A, et al. (2016). The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials. Br J Nutr 116(8):1369–1382. Abstract.
11. Saudi Ministry of Health, General Directorate of Nutrition (2012). جدول الحصص الغذائية (النخلة الغذائية الصحية). In Arabic. The Healthy Food Palm servings table.

Sources checked on 6 October 2026. Values are rounded to one decimal place.

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