Should I weigh food raw or cooked?

Raw is more consistent, because cooking losses vary with time, temperature and method. If you weigh cooked, use a cooked-specific database entry, logging 6 oz of cooked chicken against a raw entry overstates it by roughly 25%, since meat loses about that much weight as water.

Does frying add a lot of calories?

Yes. Pan-fried foods absorb roughly 5–15% of their weight in oil and deep-fried foods more, at 120 calories per tablespoon. A chicken breast at 165 calories can become 280 or more in a pan with two tablespoons of oil.

Do calories change when food is cooked?

The energy in the food changes little, but the concentration per gram changes a lot as water leaves and fat enters or renders out. Cooking also makes some foods more digestible, cooked starch and cooked protein yield more usable energy than raw.

The same ingredient, four cooking methods, four different numbers

Food databases mostly answer for a raw ingredient. What lands on your plate has lost water, gained oil, or rendered fat, and none of that is in the row you looked up.

The AIM teamOctober 30, 20264 min read

Look up "chicken breast" in a food database and you get a number. What you cannot tell from that row is whether it describes what you are about to eat.

Four things cooking does

Water leaves. Meat loses roughly 25% of its weight as water when cooked. So 8 oz raw becomes about 6 oz cooked, same energy, concentrated into less mass. Log 6 oz cooked against a raw entry and you have understated it by about a quarter.

Oil enters. Pan-frying adds 5–15% of the food's weight in oil. Deep-frying adds more. At 120 calories a tablespoon, that is the single largest swing in everyday cooking.

Fat renders out. Grilling bacon or fatty beef drips fat away, taking calories with it. Roughly the opposite of frying, and equally invisible in a database row.

Water is absorbed. Rice, pasta and legumes roughly triple in weight. A cup of cooked rice is about a third of a cup dry, and "a cup of rice" means completely different things depending on which one you meant.

What it costs in practice

Same 6 oz chicken breast:

Method	Approximate calories
Grilled, no oil	280
Baked, light oil spray	300
Pan-fried, 2 tbsp oil	450
Breaded and deep-fried	550+

Same bird. Same portion. Nearly double.

The two rules that fix most of it

Pick raw or cooked and stay with it. Raw is more consistent because cooking losses vary with time and temperature. Whichever you choose, match the database entry to it, the commonest single error in manual logging is a cooked weight against a raw row.

Log the cooking fat as its own item. People log the chicken and forget the two tablespoons of oil it cooked in, which is often more calories than the difference they were worrying about.

Why photo logging handles this better

This is the case that database lookup is structurally bad at and a photograph is genuinely good at.

An image shows the sear on the meat, the sheen of oil, the volume of cooked rice rather than dry. A model reasoning about a specific plate can account for preparation in a way that picking a row from a list cannot, because the row has no idea how you cooked it.

It is still an estimate. But it is an estimate of the food in front of you, and the assumptions come printed underneath so you can correct the one that is wrong. "Assumed pan-fried in oil" is a one-word fix if it was actually grilled.

Common questions

Should I weigh food raw or cooked?: Raw is more consistent, because cooking losses vary with time, temperature and method. If you weigh cooked, use a cooked-specific database entry, logging 6 oz of cooked chicken against a raw entry overstates it by roughly 25%, since meat loses about that much weight as water.
Does frying add a lot of calories?: Yes. Pan-fried foods absorb roughly 5–15% of their weight in oil and deep-fried foods more, at 120 calories per tablespoon. A chicken breast at 165 calories can become 280 or more in a pan with two tablespoons of oil.
Do calories change when food is cooked?: The energy in the food changes little, but the concentration per gram changes a lot as water leaves and fat enters or renders out. Cooking also makes some foods more digestible, cooked starch and cooked protein yield more usable energy than raw.