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Oatmeal calories, dry and cooked

Dry oats are 379 calories per 100 g. Cooked oatmeal is 71. That is a 5.3× difference and it is not a contradiction — cooked oatmeal is mostly the water you added. It is also, reliably, the single worst logging mistake in anyone’s breakfast.

Why the gap is so large

Oats roughly triple in weight when cooked, because they absorb water and water has no calories. A 40 g dry portion becomes about 120 g in the bowl. Weigh the bowl, log it against the dry entry, and you have just recorded 455 calories of breakfast instead of 152. Do the reverse and you under-log by the same margin.

Rice does the same thing and gets the same treatment on the rice page; oats are worse because more people cook them by eye.

The fix: weigh dry, once

Dry oats are the stable measurement. They do not change while you look at them and they do not depend on how long the pan was on. USDA’s own serving sizes are dry:

Dry weights. A US half-cup of dry oats is about 40 g.

And the same oats after cooking, for when you are logging from the bowl:

Cooked with water, no milk, no sugar.

What goes in after

Oats are cheap in calories and the toppings are not. Two tablespoons of peanut butter is 191 calories, more than a 40 g dry serving of the oats themselves. Milk instead of water, honey, and a handful of nuts routinely double the bowl. Log those separately rather than hunting for a combined entry that matches what you actually made.

Source: USDA FoodData Central, SR Legacy release 2018-04. Figures are per 100 g as published; serving weights are USDA’s own. Records used: Cereals, oats, regular and quick, not fortified, dry (FDC 173904), Cereals, oats, regular and quick, unenriched, cooked with water (includes boiling and microwaving), without salt (FDC 173905).

Common questions

Depends on the dry weight. A 40 g dry serving is about 152 calories and comes out around 120 g cooked. Cooked with water only, USDA lists 71 calories per 100 g.

Dry. It is one stable number. Cooked weight depends on how much water went in and how long it was on the heat, so it varies batch to batch.

That is the dry figure per 100 g. 100 g of dry oats is a large portion — about two and a half US half-cup servings.

No. They gain water. The calories in the pan are the same as the calories in the dry oats you put in; they are just spread across roughly three times the weight.

Compare it with

All twenty-four are on the food macros index.