Planning a meal and finding the ingredients in the fridge are two separate events. Inconveniently, the fridge was not copied in on the plan. If the rice has run out and potatoes are available, a food-exchange table can help. First decide what you want the swap to preserve. Carbohydrate, energy, protein, fat and fibre are different criteria. We favour understanding one calculation properly, then using it with a clear idea of what it answers. Here, that calculation is carbohydrate equivalence.
Equivalent by which measure?
An equivalence is a calculated relationship based on an explicit criterion. Here we use carbohydrate per 100 g of edible portion: the part actually eaten, prepared as described. That gives us a concrete question. How much of the replacement food provides roughly the carbohydrate in the starting quantity? It is a useful comparison. Deciding how much to eat and assessing the rest of your diet require more information.
Read the full food description before finding its number. Raw rice and cooked rice are different references, as are chicken with skin and skinless breast. Oil and other ingredients contribute to a prepared dish. This may look like a footnote, but it is where the calculation begins. Faultless arithmetic with the wrong food description still gives an unsuitable comparison. In a kitchen, the word “cooked” does quite a lot of work.
Eight foods with their preparation and source identified
The references below come from the 4th edition of TACO, published by NEPA/Unicamp in 2011. Values describe 100 g of edible portion in the preparation named in each row. We checked this selection on 28/10/2026. That date records our consultation; the composition values remain those of the cited edition, and the review covers these examples rather than every entry in the site’s catalogue.
| Food and preparation | Energy (kcal) | Protein (g) | Carbohydrate (g) | Fat (g) |
|---|---|---|---|---|
| White rice, type 1, cooked | 128 | 2.5 | 28.1 | 0.2 |
| Brown rice, cooked | 124 | 2.6 | 25.8 | 1 |
| Sweet potato, cooked | 77 | 0.6 | 18.4 | 0.1 |
| Potato, boiled | 52 | 1.2 | 11.9 | Tr |
| Prata banana, raw | 98 | 1.3 | 26 | 0.1 |
| Chicken breast, skinless, grilled | 159 | 32 | 0 | 2.5 |
| French-style wheat bread, Brazilian reference | 300 | 8 | 58.6 | 3.1 |
| Extra-virgin olive oil | 884 | NA | NA | 100 |
Tr = trace; NA = not applicable in the original table. These entries were not converted to zero. The olive-oil reference is specifically extra virgin. The figures do not describe every recipe, brand or variety.
The carbohydrate calculation, step by step
Call the starting food A and the replacement B. Both carbohydrate values use the same reference, per 100 g, so we can compare their proportions. First the amount of A establishes the carbohydrate involved. Then B’s value tells us how much of it would provide approximately that amount. The formula brings those steps together:
grams of B = grams of A × carbohydrate in A per 100 g ÷ carbohydrate in B per 100 g
For 100 g of cooked type 1 rice, the reference is 28.1 g of carbohydrate. Cooked sweet potato has 18.4 g per 100 g. Therefore: 100 × 28.1 ÷ 18.4 = approximately 152.7 g. Rounded to whole grams, the example becomes 153 g of sweet potato. At that rounded mass, estimated carbohydrate is 28.2 g, not exactly 28.1 g.
There is an essential arithmetic condition: B must have a positive numerical carbohydrate value. The chicken in this selection has zero in that column; olive oil has NA, meaning not applicable, which cannot be turned into a number for convenience. Neither is a valid destination for this calculation. That is a limit of the operation, rather than a judgement about their place in a meal.
Matching carbohydrate leaves other things different
We can now repeat the exercise with other foods in the table, always starting from the same 100 g of cooked rice. We rounded the masses to whole grams, then recalculated carbohydrate and energy using those rounded amounts. The small remaining differences follow from that step. Decimal places make the arithmetic visible; they do not make each serving identical to the reference sample.
| Alternative food | Calculated mass (g) | Estimated carbohydrate (g) | Estimated energy (kcal) |
|---|---|---|---|
| Brown rice, cooked | 109 | 28.1 | 135.2 |
| Sweet potato, cooked | 153 | 28.2 | 117.8 |
| Potato, boiled | 236 | 28.1 | 122.7 |
| Prata banana, raw | 108 | 28.1 | 105.8 |
| French-style wheat bread, Brazilian reference | 48 | 28.1 | 144 |
The starting rice reference provides 128 kcal, whereas the example’s 153 g of sweet potato provides approximately 117.8 kcal. Matching carbohydrate did not preserve energy. Other nutrients also need consideration according to the purpose of the comparison and the rest of the diet. The same care with the criterion helps when comparing whey by cost per quantity of protein: that measure answers a question about the product, while deciding on a meal remains a broader task.
The spoon in your kitchen needs its own reference
“A spoonful” sounds agreeably straightforward until two people serve different amounts with it. Heaped, level or packed: the way you fill a utensil changes the weight. A spoon, ladle, slice or piece can be a useful everyday measure when you know what it weighs for that food and preparation. To connect your utensil with this table, weigh what you actually served. We prefer that to inventing a universal spoon.
Zero the scale with the empty container in place. Weigh the edible part and use the reference for its current state: cooked with cooked, for example, and banana without the peel. In a recipe, water, oil and the other ingredients change the relationship between mass and composition. An ingredient’s entry describes that ingredient; understanding the finished dish requires looking at the preparation.
Tapioca is a useful example of why the description matters. Hydrated tapioca starch, dry starch and a finished preparation are different references. We left it outside this selection because we have not established a verified match between those preparations and the data used here. Identify the product or recipe first. Filling another row is easy; making the row mean something dependable is the work worth doing.
Using Darwin’s food-equivalence tool
Choose a food and enter an amount in grams. The tool calculates proportional values and shows up to 8 alternatives by carbohydrate quantity, using the registered catalogue. Think of that list as a set of possibilities to examine: food, preparation and amount all deserve a look. The displayed order is not a podium for the best swaps.
The current scope is one food and one quantity. Adding up a menu, analysing your recipe or setting an individual nutrition target are different jobs. Keep the scope of this review in view too: we checked the rows reproduced in this article. For other entries, examine the source and description before using a result. A dietitian can help connect these details with the wider circumstances that a calculator does not know.
The Brazilian Dietary Guidelines bring the meal back into view
The 2014 Dietary Guidelines for the Brazilian Population address foods, preparations, meals and ways of eating. Their approach extends beyond a prescriptive table of equivalent portions. That is a useful distinction: the formula clarifies a numerical relationship; the Guidelines ask us to consider eating in a broader setting. Getting a proportion right does not, on its own, represent following all the document’s recommendations.
We like a table when it gives the person cooking and eating more agency. It can clarify two possibilities while preference, culture, availability, variety and the rest of the meal still have a say. The number contributes information. Letting it pronounce a final verdict on a food hands a rich decision to the narrowest column on the page.
What changes when the swap is for training or racing?
Matching the carbohydrate in a piece of fruit and a sports gel starts a comparison, but practical questions remain. How will you carry it? When will you eat it? How does it fit that session and that person? The calculation has never had to pack a running-shorts pocket. Composition, practicality and individual tolerance belong in the decision too. Use the training context and individual guidance to plan intake; this table explains a proportion rather than providing a fuelling protocol.
Let the calculation sharpen the decision
Write down the food and its preparation, weigh the amount and name the criterion you want to compare. Then return to the meal: what changed beyond carbohydrate? Asking a clear question and looking carefully at the answer fits Darwin’s approach to bringing training and food records together. If that way of following your routine interests you, register for early access. At this stage the form records interest without creating a platform account.
