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How Many Carbs In An Onion? Details are here.

Carbs In An Onion

Allium vegetables like onions are excellent sources of dietary fibre, vitamins, and minerals. Onions are a vegetable that can be eaten cooked or raw. One popular way to eat onions is by putting them in a sandwich with bread and cheese. Onions are a good source of carbohydrates. A single onion contains around 6 grams of carbohydrates. These carbohydrates can help to provide energy during the day. Lets us see how many carbs in an onion are.

Nutrients in an Onion

Nutrition in onion is essential for those who want to optimize their diet. Firstly, onions are a good source of vitamins C, B6, copper, manganese, potassium, and dietary fibre. Further, they also contain a variety of antioxidants, including quercetin.

An onion fitting in your fist may weigh 60 grams. Bigger onions may weigh 80 or 90 grams or higher. Here we shall elaborate on carbs in an onion weighing 60 grams.

Carbs in an onion 60 gm

Eating an onion gives you 5.74 gm of carbohydrates and 28.80 kCal energy. Undoubtedly, carbohydrates form 79.72 % of the calories in an onion. Here is how eating an onion affects your carbs intake when you are on a calorie-restricted diet

a. 2.09 % of the daily requirement of 275 gm for a 2000 kcal diet.

b. 2.78 % of the daily requirement of 206.25 gm for a 1500 kcal diet.

c. 3.48% of the set carb limit of 165 grams for a 1200 kcal diet.

d. 4.64% of the set carb limit of 123.75 grams when following a 900-kcal diet.

As you see, when you follow a low-calorie diet, eating an onion fills the carbs quota faster than the standard 2000 kcal diet. 

For clarification, we assume carb intake at 55% of the calories of your diet plan.

The breakup of net carbs in an onion

a. Net carbs in an onion – 4.01 gm.

b. Total starch – 0.48 gm, which is 11.97 % of total carbs in an onion.

c. Total Free Sugar – 3.53 gm, which is 88.03 % of total carbs in an onion.

d. Carbs in onion are a surprise. This is because the carbohydrate in an onion is in the form of sugar. 

Details of free sugars in an onion

a. Fructose – 1.13 gm, which is 28.18 % of total carbs in an onion

b. Glucose – 0.88 gm, which is 21.95 % of total carbs in an onion

c. Sucrose – 1.51 gm, which is 37.66 % of total carbs in an onion

d. Maltose – 0.00 gm.

Sum of Total Free Sugars – 3.53 gm, which is 88.03 % of total carbs in an onion

Glycemic index of an onion

Finally, the glycemic index of onion is 15 [PMID: 23674805]. This GI is lower and thus exerts a lower glycemic load on the body.

Can people with diabetes eat an onion?

Are onions OK on keto?

Onions are a great way to add flavour to dishes while keeping their carb count low. A half-cup of chopped onion contains only 5 grams of carbohydrates, making them a perfect addition to any keto diet. They’re also a good source of flavanols and quercetin. While onions are safe to eat on keto, they do contain some sugar, so be mindful of your overall carbohydrate intake for the day if you’re trying to stay in ketosis.


In conclusion, an onion is a low-carbohydrate food that can be included in a healthy diet. They are a good source of fibre, vitamins, and minerals and have many health benefits. Onions are versatile and can be used in many dishes. 

Studies suggest that flavonoids found in onion peel extract produce a hypoglycaemic effect and are helpful for diabetes [PMID: 23674805]. Onion upper peel has a good number of flavonoids that reduces blood sugars. Therefore, eating an onion, preferably its outer pink layer, should not spike blood sugar levels. Eating an onion should not be a problem if you restrict your overall diet.

On the other hand, carbs in an onion tell us that there are more free sugars than starch. Free sugar makes blood sugar levels rise faster. Overeating onion may not be suitable for carbs management.

Hence people with diabetes should consume onions or their white layers in limit and as advised by their nutritionist. There is no one size fit for all.

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Nutritionist & Dietician
Hello everyone, I am Nutritionist Smriti Indarapu, a Post Graduate Diploma holder in Nutrition and Dietetics, practicing nutrition for the last 10 years. The journey started when we were having our family... Read full bio

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