Cooking can make rice and pasta absorb water while meat and vegetables often lose it. Calories per 100 g therefore change even though water itself provides no energy. The main error is not choosing cooked instead of raw; it is pairing a cooked weight with raw nutrition data.
Put food weighing in context with your daily calorie target
1. Match the food, its state, and the weight
Before logging a food, check its complete name, preparation state, and measured amount. “Chicken breast, raw” and “chicken breast, roasted” are not interchangeable entries. The same applies to dry versus cooked rice, dry versus drained pasta, and dried versus boiled beans.
FoodData Central explains that a food description includes characteristics such as whether the food is raw or cooked. That state is part of the underlying data, not a cosmetic label. USDA FoodData Central — Foundation Foods documentation
The practical rule is simple: raw weight with a raw entry, cooked weight with a cooked entry. If the result does not identify the state or cooking method, find a better match instead of selecting the first similar name.
- State measured: raw, dry, drained, boiled, roasted, or grilled.
- Nutrition entry: the same state and, where possible, the same cut or variety.
- Amount eaten: the edible serving, excluding bones and discarded parts.
2. Understand why 100 g changes after cooking
Rice, pasta, and dried legumes absorb water, so their weight rises and the energy is distributed across more grams. Roasted meat and vegetables commonly lose water, so their weight falls and the energy may appear more concentrated per 100 g.
USDA cooking-yield tables describe weight changes caused by moisture loss, dripping, water absorption, and fat gain or loss. These variables explain why one conversion factor cannot accurately cover every food and cooking method. USDA — cooking yields for meat and poultry
Water has no calories. Added oil, rendered fat left in the pan, discarded marinade, or cooking liquid that is not eaten can still change the energy consumed. Cooking is therefore not always just a water adjustment.
3. Raw weight is often easiest for a single ingredient
When you prepare your own serving, weigh the ingredient before cooking and use its raw or dry entry. This avoids estimating how much water your specific batch absorbed or lost. It works especially well for dry grains, pasta, oats, meat, and fish.
Measure the edible portion. If a cut contains bone, you discard the skin, or a fruit has a heavy peel, do not apply an edible-portion entry to the whole purchased weight. For packaged food, the manufacturer label is generally more specific than a generic database average.
Raw is not inherently more truthful. It is simply easier to reproduce before cooking changes weight. If someone serves you food that is already cooked, an appropriate cooked entry is more coherent than inventing a raw weight afterward.
4. If you weigh cooked food, choose a comparable cooked entry
Weigh the ready-to-eat portion and select an entry that matches the cooking method and any added fat. “Potato, boiled” does not describe fries, while “roasted chicken, meat only” may not describe a skin-on serving.
A food-composition database provides averages, not a laboratory analysis of your plate. Variety, cooking time, and draining still introduce uncertainty. Choose a reasonable match and reuse it consistently; changing entries every day can create more noise than cooking itself.
USDA FoodData Central combines several types of food-composition data and allows users to search foods by their detailed description. Reading the whole description is essential before accepting the calorie value. USDA — About FoodData Central
5. For a shared dish, calculate the recipe yield
Add the calories from all ingredients in the state in which you logged them, then weigh the entire cooked dish without its container. The dish energy density is total calories divided by final weight. Multiply that density by the weight of your serving.
Example: a recipe contains 1,200 kcal and weighs 900 g after cooking. It provides about 1.33 kcal per gram. A 225 g serving is therefore about 300 kcal, or one quarter of the batch. You do not need a universal dry-to-cooked rice ratio.
The FAO method for mixed dishes follows this logic: collect ingredient and edible-portion data, account for cooking and losses, measure the final yield, and express values per 100 g or per serving. FAO — calculating the composition of prepared dishes
6. Avoid fixed conversion ratios from the internet
A claim that 100 g dry always becomes 300 g cooked sounds convenient, but yield changes with the food, brand, soaking, water volume, temperature, cooking time, and draining. Measure the yield of your own batch when you need to divide it accurately.
Do not count oil twice. If oil is already an ingredient in the recipe, avoid a cooked database entry that also assumes added oil. Conversely, do not omit oil simply because it is no longer visible after cooking.
Food and database values naturally vary. A consistent method across several weeks is more useful than calorie-level precision built from mismatched entries.
7. Use only as much precision as your goal needs
A short weighing period can teach portion sizes and help calibrate an intake. Permanent numerical tracking is not required for fat loss or a nutritious diet; repeatable meal portions and a suitable long-term trend can work without weighing every item.
If you track, keep one convention for at least two weeks: the same favorite entries, the same measured state, and saved recipes for repeated meals. Then assess average intake and the trend related to your goal rather than one isolated meal.
If weighing causes anxiety, guilt, or eating-disorder behaviors, numerical accuracy is no longer the priority. Stop tracking and seek support from a qualified professional.
8. Turn the rule into a repeatable Nalko routine
The same decision appears at every log: which food, which state, and which serving? In Nalko, save the entries that match how you measure food and create recipes for shared dishes. You can then compare several days of intake instead of recalculating a ratio at each meal.
Nalko does not measure water lost in your pan or chemically analyze a dish. It helps you preserve the convention: match a weight to the right nutrition entry and reuse the same method.
See how to track calories and macros with consistent portionsKey takeaways
There is no universal requirement to weigh everything raw. The correct method matches food state, nutrition data, and amount eaten while remaining simple enough to repeat.
- Use raw data for raw weight and cooked data for cooked weight.
- Water gain or loss often explains the change per 100 g.
- For a shared dish, divide total calories by final cooked weight.
- Count oils, sauces, and edible parts once.
- Prefer consistency over false gram-level precision.
Frequently asked questions about raw and cooked food weight
Should you weigh rice and pasta dry or cooked?
Both methods work. Weigh them dry with a dry entry or cooked and drained with a cooked entry. For a shared pot, log the total dry amount and allocate the calories according to each cooked serving weight.
Is 100 g of raw chicken the same as 100 g cooked?
No. Chicken generally loses water and sometimes fat during cooking, so 100 g cooked started as more than 100 g raw. Yield varies by cut and method; use data for the measured state instead of a fixed ratio.
Should frozen food be weighed frozen?
Match the state specified by the label or database entry and follow package instructions. Ice glaze, sauce, and added liquid can make frozen and drained weights different. Use the declared net or drained weight where appropriate.
What should you log at a restaurant when raw weight is unknown?
Choose a reasonable cooked-food or prepared-dish estimate and accept the uncertainty. A consistent estimate is sufficient for an occasional meal; inventing a precise raw weight does not make it more accurate.