Calculating the carbohydrate content of any recipe involves three simple steps.
Here is a list of standard equivalents for the units of Imperial measuring. These can also be found in many cookbooks. It is useful to know this information in case the amount of an ingredient required in your recipe is not the amount listed in your carbohydrate book. Of course, if you cook with the Metric system, you will not need to use these.
- 1 Tablespoon = 3 teaspoons
- 1/4 cup = 4 Tablespoons
- 1 pint = 2 cups
- 1 quart = 2 pints
- 1 gallon = 4 quarts
Some recipes have obvious serving sizes. For instance, if you are making chocolate chip cookies, the serving size is one cookie. (No, it is NOT the entire batch of raw cookie dough!!) In this case, you would bake the entire batch of dough, keeping track of how many cookies your kids swipe along the way. Figure the total amount of carbs in the entire recipe and divide this number by the number of cookies you ended up with (including the "swiped" ones!). I'm sure you know by now that you never end up with the same number of cookies that the recipe says you will. Nobody makes cookies that small! The result is the number of carbs in one cookie. Now, if you decide that the serving size is more than one cookie, that's your business and nobody else's. Just multiply by the appropriate number.
Other recipes are not so clear-cut, like grandma's potato salad. In cases like this, you will need to measure the total volume of the finished recipe and divide it into what seems like a reasonable serving size. This can be a bit messy the first time you make a recipe because you end up scooping it out of one container into another using a measuring cup. Keep track and compute the total volume. Decide what amount is a reasonable serving size and divide this amount by the total volume. The result is the percentage of the total in one serving. Multiply this percentage by the total number of carbs in the recipe to get the number of carbs per serving. Once you have done this, make a note on the recipe so you'll know that the serving size is 1/2 cup (for example) and how many carbs are in each serving. One of my biggest pet peeves is a recipe that says, "Makes six servings" instead of, "Makes six servings, 1/2 cup each". It is a subtle difference but can make life soooo much easier. :-)
With some recipes, it works better to visually divide the food into equal portions and then measure the volume of one portion. A casserole served in a rectangular flat-bottomed dish can be easily divided in half with a spatula and then again into quarters, or sixths, or whatever you like. Once you have divided it, use a measuring cup to determine how much is in one serving and make a note on the recipe.
Another way to determine the number of carbs per serving is to weigh the finished product, before you serve any of it. This works well for recipes that are transferred into a serving bowl and then served "family style". An example would be stir-fried vegetables. You could weigh the entire stir-fry, and then weigh the portion you wish to eat. Divide the weight of your portion by the weight of the entire recipe to get the percentage of the stir-fry that you are eating. Then multiply this percentage by the total number of carbs in the entire recipe to get the number of carbs in your portion. Of course, for this method to work, you need to have a scale which can be "zeroed" with a pan, platter, or serving bowl on it, so you aren't including the weight of the container in your calculations. This is called a "tare" function, look for this when you are shopping for a scale. You would need to transfer the food from its cooking pan to another container for which the scale has been zeroed. Then zero the scale again for your plate or bowl and measure the food into that. Again, make a note on the recipe telling you what the serving size is and how many grams of carbohydrate are in one serving. Then, the next time you make the recipe, you won't have to go through all the weighing procedures again.
Rather than measuring the volume, some people prefer to weigh food in grams and use "carbohydrate factors" (also known as gram factors) to figure the carbs. Carbohydrate factors give the amount of carbohydrate in one gram of a particular food. There is a list of carbohydrate factors for several foods in the back of the book, "Pumping Insulin", but it doesn't cover grandma's potato salad. It is easy to figure the carbohydrate factor for any food using a scale which is set to read in grams.
Figure the total amount of carbohydrate in the recipe as described previously and weigh the entire salad (or whatever you are making). Divide the number of carbs for the total recipe by the weight in grams to get the amount of carbohydrate in one gram. This is the carbohydrate factor for that food. Then, weigh your individual portion and multiply the weight in grams by the carbohydrate factor. Again, making notes on the recipe will save you the tedium of weighing the entire recipe each time you make it.
Any food that originally started out as a plant contains carbohydrate. This includes all fruits and vegetables, as well as grains. Flour is ground grain so it contains carbs. Pasta is processed grain, so it also contains carbs. In addition to this, many dairy products such as milk and yogurt contain carbohydrate. (I suppose you could think of it as the cow or goat processing the plants...) Eggs also contain a small amount of carbohydrate. If you are unsure of which ingredients to include in your carbohydrate total, look it up in your book; if it has no carbohydrates, the book will say so.