Cooked vs raw weight: how to log rice, pasta, chicken and lentils

Here’s a puzzle that trips up almost everyone who starts weighing food: 100 g of dry rice has about 365 calories, but 100 g of cooked rice has about 130. Neither number is wrong. Cooking changes how much water is in food, so the weight changes while the calories don’t.

The rule: log the weight you measured

If you weigh it dry, log the dry entry. If you weigh it cooked, log the cooked entry. Mixing them up is one of the biggest sources of error in a food log:

• Weighing cooked rice but logging it as dry rice overcounts by almost three times.
• Weighing cooked chicken but logging it as raw chicken undercounts by about a quarter.

Foods that gain weight when cooked

Grains, pasta and pulses soak up water, so they get heavier and less calorie-dense.

Food	Per 100 g dry	Per 100 g cooked	Rough weight change
White rice	about 365 kcal	130 kcal	100 g dry → about 280 g cooked
Pasta	about 371 kcal	158 kcal	100 g dry → about 235 g cooked
Lentils	about 352 kcal	116 kcal	100 g dry → about 300 g cooked
Oats (porridge)	389 kcal	depends on the water you add	40 g oats + 250 ml water → about 290 g

The conversion depends on how much water you use and how long you cook, so treat these as rough guides. That’s exactly why it’s easiest to weigh grains dry: the dry number never changes, whatever your cooking method.

Foods that lose weight when cooked

Meat, fish and vegetables lose water, so they get lighter and more calorie-dense.

Food	Per 100 g raw	Per 100 g cooked	Rough weight change
Chicken breast	about 120 kcal	165 kcal	100 g raw → about 75 g cooked
Salmon	about 208 kcal (farmed)	206 kcal	small change, it depends on the method
Spinach	about 23 kcal	varies	100 g raw → about 25 g wilted

For meat, either weighing method is fine as long as you log the matching entry. Many people weigh it raw when portioning, then log the raw weight.

What about batch cooking?

If you cook a big pot of rice and portion it through the week, you’ll be weighing it cooked. Two ways to keep it accurate:

1. Weigh it dry, then weigh the cooked total. Say 300 g dry rice (1,095 kcal) becomes 850 g cooked. Each 100 g of that batch is 1,095 ÷ 850 × 100 = 129 kcal. Weigh your portion and use that number.
2. Use the cooked entry from the database. Slightly less precise (your rice might hold more or less water than average), but quick and close enough for most people.

The same logic works for any dish: see how to count calories in home-cooked food.

Fried and roasted food

Frying and roasting add fat. A potato that’s boiled is about 87 kcal per 100 g; as chips (fries) it can be well over 300. If you roast or fry at home, add the oil you used to the dish, or pick a database entry that matches the cooking method.

Quick reference

• Weigh grains and pasta dry when you can. It’s the most consistent.
• If you weigh cooked, log the cooked entry.
• Meat: either works, as long as the entry matches.
• Batch-cooked food: divide total calories by total cooked weight.
• Count the oil in anything fried or roasted.