When you simmer a pot of dal, kitchari, vegetable soup or spiced porridge from scratch, picking a generic "lentil soup" entry from a database is a rough guess—its oil, water-to-lentil ratio and vegetables can easily differ from your pot by 30% to 50%.
Calculating nutrition for your own recipe takes only a kitchen scale and four arithmetic steps: sum the edible raw ingredients, account for water gain or evaporation in the finished pot, and divide by the weight of the bowl you serve.
The four-step mass-balance method for home recipes
The total calories, protein, fat, carbohydrates, dietary fiber and minerals inside a finished pot equal the sum of all edible ingredients that remain in the pot. Water absorbed from simmering liquid or lost as steam changes the total weight of the batch, but because water contains 0 calories, it does not change the total energy of the entire pot.
To turn raw ingredient weights into accurate per-bowl or per-100-gram cooked numbers, follow this four-step workflow:
- Weigh the empty cooking pot first: Place your dry saucepan, Dutch oven or pressure-cooker inner pot on a digital scale and jot down its empty tare weight in grams (for example, 1,100 g).
- Weigh and log each edible raw ingredient in grams: Weigh dry grains and pulses, peeled/trimmed vegetables, dairy and—most importantly—the exact tablespoons or grams of cooking oil or ghee used for tempering. Exclude any discarded soaking water.
- Weigh the finished cooked pot and subtract the empty pot weight: After cooking, weigh the pot with the food inside (say, 2,300 g) and subtract the empty pot weight (2,300 g − 1,100 g = 1,200 g total cooked yield).
- Divide by your portion weight: If you ladle a 300 g bowl from that 1,200 g cooked batch, your bowl is 300 ÷ 1,200 = 0.25 (25%) of the entire recipe's calories and nutrients.
How cooked yield changes nutrient density per 100 grams
Recording the final cooked batch weight is also how recipe databases calculate nutrient density per 100 grams of cooked food. Depending on the cooking method, total recipe weight moves in one of two directions:
When roasting or baking vegetables, flatbreads or paneer, moisture evaporates in the oven and the cooked yield weighs less than the raw ingredients—concentrating the same total calories into fewer grams (higher energy density per 100 g cooked). When simmering dry rice, oats or lentils in water, the dry ingredients absorb water and the cooked batch weighs much more than the dry grains—spreading the same total calories across a heavier pot (lower energy density per 100 g cooked). The following arithmetic example is a hypothetical kitchen illustration:
- Hypothetical simmering example: Suppose raw dry ingredients + tempering fat total 350 g and provide 1,000 calories total. After simmering with water, the finished pot of dal weighs 1,000 g cooked. The entire pot still holds 1,000 calories, so 100 g of cooked dal provides (1,000 ÷ 1,000) × 100 = 100 calories per 100 g.
- Hypothetical roasting example: Suppose 1,000 g of raw cubed vegetables tossed with oil provides 800 calories total. After oven roasting evaporates 200 g of water, the finished tray weighs 800 g cooked. Because all 800 calories remain on the tray, 100 g of roasted vegetables now provides (800 ÷ 800) × 100 = 100 calories per 100 g.
Measuring cooking fats and understanding vitamin retention factors
In everyday kitchen tracking, the largest source of error in a homemade recipe is rarely the vegetables or spices—it is pouring cooking oil, ghee or coconut milk by eye. Because 1 tablespoon (about 14 g) of oil or ghee adds roughly 120 to 125 calories, measuring your tempering fat with a spoon or scale keeps your recipe totals reliable.
While calories, protein, fat, fiber and minerals stay inside a one-pot dish where all cooking liquid is eaten, USDA FoodData Central documentation notes that scientific recipe datasets (such as Survey Foods / FNDDS) also apply nutrient retention factors to estimate partial cooking losses of heat- and water-sensitive vitamins such as vitamin C, folate and thiamin.
Sources & Classical References
- USDA FoodData Central: Data Type Documentation — Describes how USDA reference and survey datasets (FNDDS) calculate nutrient values for multi-ingredient recipes using ingredient weights, moisture changes and nutrient retention factors.
- FDA: Serving Size on the Nutrition Facts Label — Explains how serving weights and multi-serving containers scale proportionally.
