1 piece (medium) of Onion (raw) (80 g) has 32 calories. That works out to 40 calories per 100 g. It contains 7.4 g of carbs, 0.9 g of protein, 0.1 g of fat and 1.4 g of fiber. Its 5.9 mg of Vitamin C covers 7% of the Daily Value. Its glycemic index is 15 (low), so it raises blood sugar slowly.

Onion (raw) Nutrition Facts

Selected: 100 g

KCAL / 100G

Carbs

9.3g

· 3% DV

Protein

1.1g

· 2% DV

Fat

0.1g

· 0% DV

Fiber

1.7g

· 6% DV

DV is the share of the daily value covered, on a 2,000 kcal reference diet.

Calories come from: Carbs 88% · Protein 10% · Fat 2%

Onion (raw) Vitamins & Minerals

Vitamins

Vitamin C

7.4mg · 8% DV

0.12mg · 7% DV

Folate

19µg · 5% DV

0.05mg · 4% DV

Minerals

Phosphorus

29mg · 4% DV

Potassium ⭐

146mg · 4% DV

Calcium

23mg · 2% DV

Magnesium

10mg · 2% DV

How Nutritious Is Onion (raw)?

Nutrient density

High

60/ 100

How many vitamins, minerals and how much fiber this food carries per calorie. A high score means a lot of nutrition for few calories.

Satiety score

Medium

46/ 100

An EatBetter score computed from fiber, protein and calorie density. A high score means staying full longer on the same calories.

Both scores are calculated per 100 g and do not change with the selected portion. The satiety score is EatBetter's own calculation, not a clinical measure.

Onion (raw) Glycemic Index

GLYCEMIC INDEX

Low

0 Low5570100

GLYCEMIC LOAD

1.4

Low

Accounts for portion size — a more realistic measure than GI alone.

How to Burn Off Onion (raw)

To burn the 40 calories in 100 g:

🚶

10min

Walking (5 km/h)

🏃

4min

Running (8 km/h)

🚴

5min

Cycling

🏊

5min

Swimming

Times are calculated with the MET equation for a 70 kg adult. Actual burn varies with your weight, age and pace.

Is Onion (raw) Processed?

NOVA 1

Unprocessed

1. Unprocessed

2. Minimally Processed

3. Processed

4. Ultra-Processed

NOVA classifies foods into 4 groups by industrial processing. NOVA 1 (unprocessed) is the healthiest.

Does Onion (raw) Contain Allergens?

No known major allergens

Gluten free

Dairy free

Eggs free

Peanuts free

Tree nuts free

Fish free

Soy free

Sesame free

Which Diets Is Onion (raw) Good For?

Vegan

✓ Suitable

Vegetarian

✓ Suitable

Gluten-Free

✓ Suitable

Dairy-Free

— Not suitable

Mediterranean

✓ Suitable

Paleo

✓ Suitable

Whole30

— Not suitable

DASH

— Not suitable

Keto

✓ Suitable

Low FODMAP

— Not suitable

Onion (raw) Fat Profile

SATURATED

0.03g

MONOUNSATURATED

0.01g

POLYUNSATURATED

0.02g

⚖️

Omega 6:3 ratio 2:1

Below the ideal 4:1 — a good omega balance.

Compare Onion (raw)

🧅vs🍅

Onion (raw) vs Tomato22 kcal more per 100 g

→🧅vs🥗

Onion (raw) vs Mixed Green Salad22 kcal more per 100 g

→🧅vs🫑

Onion (raw) vs Red Pepper9 kcal more per 100 g

→🧅vs🥄

Onion (raw) vs Boiled Beetroot4 kcal fewer per 100 g

→

Foods Similar to Onion (raw)

🍅

Tomato

18 kcal

🥗

Mixed Green Salad

18 kcal

🫑

Red Pepper

31 kcal

🥄

Boiled Beetroot

44 kcal

🫑

Green pepper

20 kcal

🥗

Potato Salad

110 kcal

🥗

Arugula

25 kcal

🥕🥦🍆

Oven-Roasted Mixed Vegetables

65 kcal

Frequently Asked Questions About Onion (raw)

How can I make raw onion taste less sharp?

Soak sliced or chopped onion in cold water for 10–15 minutes, then drain it well. This mellows the pungency while keeping the onion crisp.

Why do onions make your eyes water, and how can you reduce it?

Cutting an onion releases sulfur-containing compounds that irritate the eyes. A sharp knife, a chilled onion, and good ventilation can help reduce tearing.

Can raw onion cause bloating or stomach discomfort?

Yes. Onion contains fructans, fermentable carbohydrates that can trigger gas, bloating, or abdominal discomfort in some people, especially those with IBS. Try a smaller serving or choose cooked onion if you are sensitive.

Does raw onion cause bad breath?

Yes, its sulfur compounds can linger in the mouth and sometimes on the breath after digestion. Brushing teeth and the tongue, drinking water, and eating fresh herbs such as parsley may help lessen the smell.

How long does chopped raw onion keep in the fridge?

Store chopped onion in a sealed container in the refrigerator and use it ideally within 5–7 days. Discard it if it develops mold, an off smell, or a slimy texture.

Can raw onion be frozen?

Yes, chopped onion can be frozen in an airtight container or freezer bag. It will become softer after thawing, so it is best used in soups, sauces, and cooked dishes rather than salads.

Does cooking onion destroy all of its benefits?

No. Cooking changes onion’s texture and some heat-sensitive sulfur compounds, but it does not make onion nutritionally useless. Raw onion has a sharper flavor, while cooked onion is often easier to digest.

What foods pair well with raw onion?

Raw onion works well with beans, eggs, fish, meat, yogurt-based dishes, and salads; lemon juice or vinegar helps balance its bite. Adding it to a meal with protein and fiber can make the meal more satisfying than eating it alone.

Can onion replace antibiotics for an infection?

No. Onion can be part of a healthy diet, but it is not a substitute for prescribed antibiotics or medical care for a bacterial infection.

Should people taking blood thinners be careful with raw onion?

Typical food amounts are generally not a concern for most people, but onion supplements or unusually large intakes are less well studied for interactions. If you take anticoagulants, have a bleeding disorder, or are preparing for surgery, ask your clinician about regular high-dose use.

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Nutrition data compiled from USDA FoodData Central and scientific sources.

· Last updated: August 24, 2026