How to use the nutrition facts label
To succeed on keto and low carb, we recommend you learn how to read the nutrition facts label on packaged foods.
This label can help you understand how healthy a packaged-food item really is and help you compare two products to see which is better suited to your low-carb lifestyle. The label is especially helpful for catching well-camouflaged sugars and comparing the carbohydrate content of similar items.
How to use the nutrition facts label:
1. Check for hidden sugars
Did you miss a cryptically named sugar hidden on that ingredient list? Check the grams of sugar on the nutrition facts label (circled in pink). You will find this under the total carbohydrate grams, right after the fiber. This sugar number includes both naturally occurring sugars (like the natural sugar, fructose, found in lemon juice) plus added sugars (like the sugar or corn syrup added to some salad dressings). So all the sugar comes together in just one number.
Grams of sugar is shown per serving. This E.V.O.O. Lemon Herb Dressing has 3g of sugar per serving (circled in pink, above).
The nutrition facts label always shows the number of servings per container (circled in red). If you plan to eat more than one serving, you will need to multiply the grams of sugar per serving by the number of servings you will consume. If you pour about 4 tablespoons of dressing on your salad, that would be two servings, so six grams of sugar. That is a lot of sugar for a generous pour of salad dressing. Perhaps you can find another brand with less sugar? (Or make a low-carb version at home with no sugar.)
2. Calculate net carbs
For low-carb eaters, perhaps the most common use of the nutrition facts label is to calculate how many grams of net carbs1 are in their food. It is a relatively easy calculation; once you get the hang of it, it takes just seconds.
Calculating net carbs can be a great way to compare two similar products. For example, consider the label on the chocolate bar to the left – the Green & Black 85% Cacao Bar.
How do you calculate the number of net carbs in that chocolate? Do these four things:
1. Check the serving size
First, look at the serving size, (circled in red, above). How much chocolate is in one serving? A square? A cup? Half the package?
As you can see, the serving size for this chocolate is 40 grams, or 12 small squares.
2. Check carbs per serving
Second, check the total grams of carbohydrate per serving (circled in blue, above).
This chocolate has 14 grams of carbs per serving.
3. Calculate net carbs per serving
Third, check the grams of dietary fiber per serving, (circled in green, above). Calculate net carbs by subtracting the fiber (green) from the total carbohydrates (blue). This chocolate has 9g net carbs per serving (14g carbs – 5g fiber = 9 net carbs).
4. Calculate how many net carbs you will eat
Finally, multiply the number of servings you’ll eat by the net carbs per serving.
Let’s say you want to eat six small squares of chocolate (about half a serving, or 20 grams). That’s 4.5 grams of net carbs (0.5 serving * 9g net carbs).
BUT, if you were to eat the whole chocolate bar (2.5 servings), you would eat 22.5 grams of net carbs (2.5 servings * 9 net carbs) – A LOT of carbs.
This chocolate bar is certainly low-carb. And, when consumed in small amounts, is even keto approved. But buyer beware—it’s easy to overeat.
Let’s look at the nutrition facts label for another dark chocolate option, Salazon’s delicious Dark Chocolate with Sea Salt and Almonds:
As you can see, this bar has 13g of net carbs2 per serving. If you eat a half serving (in this case, 1/4 of the bar, but still 20 grams), you would consume 6.5g of net carbs. This meets some low-carb eaters’ personal carb guidelines. But for some, especially keto eaters, the net carbs in this bar is too high. Instead of placing it in the cart, it goes back on the shelf.
You can do this sort of a comparison with any two products. If you are choosing a spaghetti sauce, why not quickly calculate which has fewer net carbs per cup? It might be the same, but not always. Even a package of something as standard as full-fat cream cheese can have fewer net carbs per ounce than another brand.
If you are concerned about eating enough (or too much!) protein, you can use steps 1, 2 and 4,3 above, to calculate how much protein you would be getting from eating a serving or two of an item.
3. Consider macronutrient balance
Another way to use the nutrition facts label is to consider the macronutrient balance of a product. The energy in your food comes from three macronutrients: carbohydrates, fat, and protein. In essence, you try to answer the question, “How much of the calories are coming from net carbs?” But there is a shortcut to find your answer without having to pull out a calculator and make that calculation.
This is especially useful if considering a snack that will be eaten alone, rather than an item that will be consumed as part of a meal. It is also helpful for choosing between two possible snacks, where the grams of net carbs are about the same.
Very simply, after calculating net carbs, take a look at the grams of fat and protein on the nutrition facts label, too.
The net carbs in this KIND bar are about 9g, and say you are comparing it to another snack with 8-10g net carbs. They are close. How do you pick? Look at the grams of fat and grams of protein (highlighted in yellow, above). In general, the more fat, the better. Products with more fat or more protein will have more calories, but they also provide a more balanced source of energy. In effect, the fat and protein dilute the carbs. This help minimize blood sugar spikes and future snacking.
4. Consider energy density
Nutrition labels can help you understand how calorically dense a food item is. Although low-carb eaters typically don’t have to bother counting calories (thank goodness!), it is nice to consider how many calories might be in a snack or meal component… just so you don’t overfeed yourself and regret it later.
Again, the calculation is very simple:
1. Check the serving size
The nutrition facts always have both “Serving Size” and a “Servings per Container/Package” listed at the top of the label. If you are holding a snack pack that looks like it is one serving, don’t assume that the nutrition facts listed cover the whole bag. Always check. Is it a cup? Is it half a bag? In this case, these raw pecans have a serving size of one cup (circled in turquoise).
2. Check calories per serving
Calories per serving is always listed near the top of the nutrition facts label. In this case, a cup of pecans contains 684 calories (circled in brown).
3. Put the two together
Make a mental note—something like this: “Oh. One quarter cup of pecans has about 170 calories. They are a dense source of energy; I won’t need more than a handful in my lunch.”
Most of the fatty foods you eat on a low-carb or keto diet pack a lot of calories. They are usually delicious, but often, a little goes a long way. It can be easy to eat more than you need. Although some eaters pay no attention to calories, others find that it helps to have a general idea of how many calories are in a serving of the food before they decide how much to eat.
The new nutrition facts label
Changes to the nutrition facts label are a-coming…but no time soon. The FDA has announced a delay until 2020. Will the new labels be better? Slightly. It will be easier to see the serving size and total calories, which is a plus. And manufacturers will be under pressure to clean up their act when it comes to designating a reasonable serving size for each product. The new labels will call out added sugars separately, which is nice but not critical, since sugar is sugar.
There is certainly a lot more information on the nutrition facts label, but most of it isn’t that important. Use these tips to check for hidden sugars, and to calculate one of the following: net carbs, macronutrient balance, and energy density. In most cases, looking at one or two of these will suffice; you will know what you need to know.
There are two companion guides with more information about navigating the grocery store and on ingredients to avoid:
For more basics, check out our simple but thorough beginner’s guide to the keto diet:
About the author
Jenni Calihan created the non-profit, Eat the Butter, to start a mother-to-mother conversation about diet and health. She advocates for real-food-more-fat eating, and has been feeding her family (four kids) for twenty years.
Practical low-carb guides
The human body doesn’t break down all forms of carbohydrate. Net carbs refers to the carbohydrates the body is able to break down. ↩
Net carbs = sugar + starch. So this bar has 10g sugar + 3 grams starch for a total of 13g net carbs. ↩
no need for step three, as you do not need to deduct fiber grams from your protein count ↩