Raw versus cooked food weight: match the quantity to the record

Match the food state before multiplying

Read whether the reference describes a raw, cooked, drained or prepared food. Then use a quantity measured in that state. A cooked-rice weight multiplied by a dry-rice energy density can produce a large error even when both source numbers are reasonable on their own.

This is a unit-matching problem. “100 g rice” is incomplete because water content and preparation are part of the definition. Meat records also need the cut, visible fat, cooking method and edible portion. If your quantity includes a bone or peel that you did not eat, it does not match a reference for edible food.

A water-only example

Imagine 100 g of dry grain with 360 kcal becoming a 300-g cooked batch after absorbing water. If no energy-bearing ingredient is added or discarded, the batch still contains 360 kcal. Its cooked density is 360 ÷ 300 × 100 = 120 kcal per 100 g.

These are illustrative values, not a fixed yield for every rice or cooking method. Using 150 g of cooked grain with the dry density would give 540 kcal and count the absorbed water as if it were more dry grain.

Cooking can change more than water

The simple example assumes that only water changes. Real cooking may add oil, discard liquid or lose rendered fat and solids. USDA cooking-yield research distinguishes moisture and fat changes under specific preparation protocols. A universal “cooked weight is always a fixed fraction of raw weight” rule is therefore unreliable.

For home recipes, record the ingredients and use the measured edible cooked yield. For a ready-cooked food, a reference matching that preparation may be more useful. Do not apply a raw-to-cooked multiplier and a cooked reference at the same time; that can correct the same change twice.

Choose one consistent method

1. For an ingredient calculation, weigh edible raw ingredients and include added fats.
2. After cooking, weigh the edible batch without the pot.
3. Describe any important discarded components.
4. Allocate the batch estimate by the portion you actually eat.

Alternatively, use a well-matched cooked-food reference and cooked portion weight. The methods can both be useful, but mixing their denominators is the common error.

When the preparation is unknown

For a restaurant meal, you may know only an approximate cooked portion. Use a prepared-food reference that resembles it and retain uncertainty around recipe and oil. A photo can help identify components; it cannot reconstruct every cooking loss.

Save the preparation state with the entry so a future “same meal” still has a readable meaning. Try the recipe calculator for ingredient-based arithmetic, or explore cooking yield when comparing whole batches.