Net carbohydrates are the total amount of carbohydrates a food contains minus the amount of fiber the food contains, and it is measured in grams. For example, a 1-ounce serving of almonds contains 6.1 grams of carbohydrates and 3.4 grams of fiber, giving it 2.7 grams of net carbohydrates.
Net carbohydrates are a key concept in the Atkins diet, which restricts carbohydrate intake, and in other diets based on a food's glycemic index, which measures how fast the food causes blood sugar levels to rise after consumption. Simple or refined sugars and starches cause a fast rise in blood sugar, while carbohydrates with high fiber contents move more slowly through the digestive system and are not entirely digested.
Even though a food has a low number of net carbohydrates, it may not be healthy. Many processed food products that advertise that they are low in net carbohydrates are still high in calories. Some of these foods also depend on sugar alcohols for flavor, and these sweeteners can cause diarrhea and other gastrointestinal problems. Also, the long-term effects of consuming large amounts of sugar alcohols are not known, as of 2015. The best sources of foods low in net carbohydrates are vegetables, fruits and whole grains, which provide nutrients and antioxidants.