In this article
To calculate carbohydrates in a recipe, sum the contribution of each ingredient and then divide by the yield. The calculation requires using weights and compatible data. It is an estimate based on ingredients, not a laboratory test.
The examples in this article are entirely fictional. They do not describe a real recipe, do not indicate a recommended quantity, and should not be used to dose insulin.
Choose the correct data for each ingredient
Use the product packaging or a table that matches the food and preparation. A raw food record should not be automatically applied to the same weight of cooked food. Check if the weight represents the edible portion, removing skins or other components not included in the preparation.
If the package provides values per serving, convert using the weight of that serving. Do not mix spoons, units, and grams without a known correspondence.
Multiply by the weight used
The formula is: carbohydrate from ingredient = value per 100 g × weight used ÷ 100. Perform this calculation for all ingredients entering the recipe, including sauces, beverages, and complements.
- Ingredient A: 200 g, with 3 g per 100 g, contributes 6 g.
- Ingredient B: 100 g, with 4 g per 100 g, contributes 4 g.
- Ingredient C: 50 g, with 8 g per 100 g, contributes 4 g.
The total of the fictional batch is 14 g of carbohydrates. The names A, B, and C represent only the mathematical example, not foods with these values.
Divide by the actually served portion
If the batch is divided into four equal portions, each will have 3.5 g. This division works when portions have the same composition and quantity.
Another way is to weigh the final yield. If the same prepared dish weighs 400 g, a 150 g portion will have 14 × 150 ÷ 400 = 5.25 g. This portion is larger than one of the four equal parts; therefore, the results are not equal.
When ingredients are not uniformly distributed, dividing by weight may not represent each dish with the same precision. Consider this limitation when recording the meal.
Water and yield change the base
Losing water during cooking alters the final weight and the value per 100 g. This does not automatically eliminate the total carbohydrates from ingredients. If part of the preparation or a liquid is discarded, do not invent how much carbohydrate left with it; seek a compatible value or acknowledge the uncertainty.
Label rounding and natural food differences also limit precision. Adding more decimal places to the result does not make the source more exact.
Do not mix fiber conventions
In Brazil and European Union labels, carbohydrates exclude fiber. In the United States, Total Carbohydrate includes fiber. TACO uses carbohydrates by difference, which include fiber. Identify these differences and do not automatically subtract fiber from any number.
Also do not deduct all sugar alcohols by a universal formula. For medical treatment-related counting, follow the guidance of the healthcare team. Culinary counting helps to know the recipe, but does not determine if it is suitable for you.
Related readings
- Keto meal prep: preparation, storage and freezing
- Almond flour or coconut flour: differences and substitutions
- Ready-made sauces on keto: sugar, starch and portions
- Risks and precautions before starting the ketogenic diet
Sources and limits
- Anvisa: nutrition labelling in Brazil
- FDA: understanding the Nutrition Facts label
- Unicamp: Brazilian Food Composition Table (TACO)
Informational content prepared with support from artificial intelligence, without independent clinical review. It does not replace assessment by a doctor or dietitian. Meal examples are not an individual meal plan or tested recipes. The image is illustrative and was generated by AI.
European Union: food information regulation
Mariana is passionate about a healthy lifestyle.
