An average size onion of 160g has 14.9g in total carbs. This carbohydrates count applies to raw onion and its common varieties of white onion, yellow onion and red onion.
The size of the onion matters. 14.9g in total carbs mentioned above is for a 160g size onion. On the other hand, a cup of sliced onion, which is about 115g, has about 11g in total carbs. This is important to know when making calculations for recipes. The amount of onion going into the recipe matters.
The most useful and nearly accurate way of determining carbs in an onion is to go by the amount or weight of sliced onion in a standard measuring cup. This is because raw whole onions come in different sizes which translates to varying amounts of carbohydrates in them.
In addition, most people peel onions before use. It is estimated that 74% of the onion’s weight is what remains and is useable after peeling the onion. This means about 16% of the onion’s weight is generally thrown away as waste. This detail is important when aiming to work with more accurate figures of what is finally consumed as carbs after all is said and done.
While in essence varieties won’t matter when considering carbs in onions, red onion has been shown to have an even better health benefits profile than its other family members. For example, you may see our write-up on calories in red onion here.
Net Carbs in Onions
160g of onion have net carbs of 12.4g
Often times, when one comes across onion carb numbers, they tend to be stated as total carbs although this may not be explicitly mentioned. It is safer to assume that the stated amount of carbohydrates is for total carbs.
Net carbs in onions refers to the carbs count that remains after the subtraction of fiber. The fiber component in 160g of raw onion is 2.3g. This is about 15% of the total carbs in the onion.
The fiber constituent in a given onion weight is always smaller but significant. This is to say when discounted, it significantly reduces the remaining level of carbohydrates in the onion.
It must must be stated that the concept of net carbs which is sometimes referred to as active carbs or impact carbs is not official. For example, the FDA in the United States does not recognize this term. It is a concept invented by food companies to help consumers understand the exact number of carbs that may make an impact in a diet.
In the case of onions, the fiber component is not considered an active carbohydrate which impacts the body. Much of fiber as also found in fruits such as apples is not digested. It passes through the body’s digestive system undigested at all. It is for this reason that fiber is thought to have no impact on active carbs in onions.
Onion Calorie Profile
Carbs in an onion contribute to the total calorie count of the onion. The source of calories in an onion are carbs, protein and fat. In the 160g of onion example, total carbs are 14.9g, protein is 1.8g and fat is 0.2g. The total amount of calories is therefore 64 calories.
The graph above illustrates the calorie profile of an average size onion of 160g. We also have a separate write-up on this here.
Lowest Carbs Onion Type
Green onions or scallions have the lowest carbs of all onion varieties. A full cup of green onions has 8g in total carbs. carbs and 6g in net carbs.
The green leaves or tops in scallions is what is consumed. Thus the carb count is based on this part of the onion ignoring the white stalk and miniature bulb at the bottom.
Carbs in Cooked Onions
A cup of chopped and cooked onions with a serving weight of 87g has total carbs of 7g and 115 calories.
Cooked onions do not appear to have any higher carbs than the same amount of raw onion. This, however, depends on the cooking method used and ingredients added to the recipe.
Carbs in cooked onions can easily increase if the recipe used to prepare the onion introduces ingredients with carbs. For example, if the onion is sautéed in butter or olive oil which have no carbs, but coated with flour, the carbs count of the final product to be consumed will change.
