1 piece (medium) of Baked Onion (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.

What is Baked Onion?

Baked Onion is onion cooked whole or in large pieces until its layers soften and the edges turn golden. The oven brings out its natural sweetness, making it a simple home-style side dish rather than a preparation tied to one specific region. It can be made with a whole onion or cut to suit the meal.

Serve it warm alongside roasted vegetables, meat, or a grain bowl; it also works chopped into salads. The texture is tender and juicy, with sweeter, lightly browned edges. Baked onion is low in calories and provides fibre, with 40 calories per 100 grams. For a lighter plate, bake it with little added oil and pair it with other vegetables or a protein-rich main.

Baked Onion 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%

Baked Onion Vitamins & Minerals

Vitamins

0.13mg · 8% DV

Vitamin C

7.4mg · 8% DV

Folate

19µg · 5% DV

0.04mg · 3% DV

Minerals

Phosphorus

29mg · 4% DV

Potassium ⭐

146mg · 4% DV

Calcium

23mg · 2% DV

Magnesium

10mg · 2% DV

How Nutritious Is Baked Onion?

Nutrient density

Medium

45/ 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.

Baked Onion 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 Baked Onion

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 Baked Onion Processed?

NOVA 2

Minimally Processed

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 Baked Onion 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 Baked Onion Good For?

Vegan

✓ Suitable

Vegetarian

✓ Suitable

Gluten-Free

✓ Suitable

Dairy-Free

— Not suitable

Mediterranean

✓ Suitable

Paleo

✓ Suitable

Whole30

— Not suitable

DASH

— Not suitable

Keto

— Not suitable

Low FODMAP

— Not suitable

Baked Onion Fat Profile

SATURATED

0.02g

MONOUNSATURATED

0.01g

POLYUNSATURATED

0.03g

⚖️

Omega 6:3 ratio 2:1

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

Compare Baked Onion

🧅vs🍅

Baked Onion vs Tomato22 kcal more per 100 g

→🧅vs🥗

Baked Onion vs Mixed Green Salad22 kcal more per 100 g

→🧅vs🫑

Baked Onion vs Red Pepper9 kcal more per 100 g

→🧅vs🥄

Baked Onion vs Boiled Beetroot4 kcal fewer per 100 g

→

Foods Similar to Baked Onion

🍅

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 Baked Onion

How do you make a Baked Onion?

To make a Baked Onion, peel it, place it whole or halved in a baking dish, and season with a little oil, salt, and pepper. Bake until the center is tender and the edges are golden; larger onions take longer to soften.

Which onions are best for a Baked Onion?

Yellow onions are a reliable choice for a Baked Onion because they soften well and develop a mellow, sweet flavor. Red onions also work and bring a stronger color and slightly different taste. Choose onions of similar size if baking several together.

Can you bake a Baked Onion with the skin on?

Yes, you can bake a Baked Onion with its papery skin on, which helps protect the inner layers from drying out. Remove the outer skin before eating. Rinse the onion well under running water before baking, even if you plan to peel it.

Should you wrap a Baked Onion in foil?

You can wrap a Baked Onion in foil to trap steam and make the inside especially soft. The foil limits browning, though, so unwrap it near the end if you want golden edges. Bake it uncovered from the start for a more roasted surface.

How can you tell when a Baked Onion is done?

A Baked Onion is done when a knife slides easily into its center and the layers feel soft. The outside may be golden or lightly collapsed. If the center is still firm, continue baking and check again rather than relying only on the color.

How long does a Baked Onion keep in the fridge?

A Baked Onion keeps for about three to four days in the refrigerator when cooled and stored in a covered container. Refrigerate it promptly rather than leaving it out for hours. Reheat only the portion you plan to eat, until it is hot throughout.

Can you freeze a Baked Onion?

Yes, a Baked Onion can be frozen, although thawing makes its texture softer and sometimes watery. Let it cool, portion it into a sealed freezer-safe container, and thaw it in the refrigerator. Use thawed onion in soups, sauces, or other cooked dishes.

What should you serve with a Baked Onion?

A Baked Onion pairs well with roasted meat, chicken, fish, or a grain-based side such as rice. It also works in sandwiches and warm salads. Add fresh herbs or a spoonful of yogurt sauce to balance its mellow, sweet flavor.

Does a Baked Onion taste sweeter than a raw onion?

Yes, a Baked Onion usually tastes sweeter and less sharp than a raw onion. Heat softens its pungent flavor and brings out its natural sweetness. More browning gives the outside a deeper, lightly caramelized taste while the center stays tender.

Can a Baked Onion cause gas or bloating?

Yes, a Baked Onion can cause gas or bloating in people who are sensitive to onions; cooking does not remove every trigger. Try a smaller serving and notice how you feel. If symptoms are persistent or severe, discuss them with a healthcare professional.

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Nutrition data compiled from USDA FoodData Central and scientific sources.

· Last updated: September 24, 2026