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Raw vs Cooked Onions: How Do They Compare?

Sonia Fuller, Content Writer

Written by Sonia Fuller, Content Writer. Updated on March 12, 2023.

Onions are vegetables that can be consumed both raw and cooked, but which one has more nutritional value?

Onions are not an excellent source of any particular vitamin.

However, they contain vitamin C, vitamin B1 (Thiamine), vitamin B6 (Pyroxidine), and vitamin B9 (Folate) in a small amount.

Raw vs Cooked Onions Nutrition

Are cooked onions more nutritious? Let’s make an in-depth comparison of raw vs cooked onions and see.

This comparison will start by comparing the caloric value of raw and cooked onions and their macronutrients and then go more in-depth by analyzing their vitamin and mineral contents.

First, let’s see how 100 grams of raw onions compare to 100 grams of cooked onions.

The second table compares 100 grams of raw onions and the caloric equivalent of cooked onions.

After cooking 100 grams of raw onions, you will get around 86 grams of cooked onions, and that comparison is shown in the second table.

Raw Onions (100 grams)Cooked Onions (100 grams)
Energy38 kcal44 kcal
Carbs8.46 g10.15 g
Sugar5.8 g4.73 g
Fiber1.7 g1.4 g
Protein0.86 g1.36 g
Fat0.08 g0.19 g
Saturated Fat0.042 g0.031 g

How do macronutrients change after cooking 100 grams of raw onions?

So if you cook 100 grams of raw onions, you will get around 86 grams of cooked onions, and this table shows how macronutrient content changes after cooking.

Raw Onions (100 grams)Cooked Onions (86 grams)
Energy38 kcal38 kcal
Carbs8.46 g8.77 g
Sugar5.8 g4.09 g
Fiber1.7 g1.21 g
Protein0.86 g1.17 g
Fat0.08 g0.16 g
Saturated Fat0.042 g0.03 g

Raw vs Cooked Onions Calories

Cooking foods doesn’t change their micronutrient quantity and availability. It also changes its weight because water is either evaporated or absorbed. By cooking, onions lose weight, so the amount of calories in 100 grams is higher in cooked onions.

If you want to lose weight, calories are probably the most important thing you should consider.

That said, here’s how raw and cooked onions compare for weight loss: onions onions are slightly lower in calories, with 38 calories per 100 grams, compared to 44 calories per 100 grams of onions.

Protein Content in Raw Onions and Cooked Onions

Cooked Onions onions are higher in protein and have around 37% more protein than onions onions.

Cooked Onions onions offer 1.4 grams of protein per 100 grams, while onions onions offer 0.9 grams.

Carbohydrate Content in Raw Onions and Cooked Onions

In this section, we’ll take a deeper look into the carbohydrate content in raw and cooked onions.

Continue reading to find out how raw and cooked onions compare in terms of total carbs content, sugars, and dietary fiber.

Total Carbs

The total amount of carbs is around 17% higher in cooked onions than in raw onions.

They have 10.2 grams per 100 grams, compared to 8.5 grams in raw onions.



Speaking of sugars in onions, cooked onions contain less sugar than raw, 18% precisely.

100 grams of cooked onions contain 4.73 grams of sugar, while the same amount of raw onions contains 5.8 grams.

Dietary Fiber

Finally, we will discuss the fiber content in raw and cooked onions.

Dietary fiber can help with weight management by making you feel fuller longer and help with digestion by promoting regular bowel movements and reducing constipation and diarrhea.

It can also lower the risk of heart disease by reducing cholesterol levels.

Additionally, it can help regulate blood sugar levels, which is beneficial for individuals with diabetes. Fiber also helps feed the beneficial bacteria in the gut that promote overall health.

If you are looking to increase your fiber intake, raw onions are a better option for you.

They have 1.7 grams of fiber per 100 grams, while cooked onions provide 1.4 grams of fiber.

Fat Content in Raw Onions and Cooked Onions

Like other plant foods, onions are naturally cholesterol free and free of trans fats.

Here’s the total amount of fats in raw and cooked onions:

  • Raw Onions: 0.1 grams per 100 grams
  • Cooked Onions: 0.2 per 100 grams

Saturated Fat

Consuming too much saturated fat has been linked to an increased risk of heart disease, as it can raise LDL (bad) cholesterol levels in the blood.

However, not all saturated fats are created equal. Some types of saturated fats, such as those found in coconut oil and palm oil, may have different effects on cholesterol levels and heart health compared to others, such as those found in butter and cheese.

The American Heart Association recommends that people limit their intake of saturated fats.

Additionally, it is important to replace saturated fats with healthier fats, such as monounsaturated and polyunsaturated fats, found in foods such as avocados, nuts, and seeds.

When it comes to saturated fats, onions onions and onions contain the same amount of saturated fats, 0 grams per 100 grams.

Raw Onions vs Cooked Onions Vitamins Content

In the following two sections, we will take a closer look at raw vs cooked onions’ vitamins and mineral contents.

As we mentioned before, 100 grams of raw onions weigh 86 grams after cooking, so our vitamins and minerals comparison will use these weights: 100 grams of raw onions or 117 grams of cooked onions.

Unfortunately, most vitamins are sensitive to heat and water.

Cooking can decrease the levels of certain vitamins, including both water-soluble vitamins like vitamin C and B vitamins, as well as fat-soluble vitamins such as A, D, E, and K.

Vitamins soluble in water will leach into the cooking water, while vitamins soluble in fat will leach into cooking oils.

Only two vitamins, K and B-3, or niacin, are stable enough to hold up well during cooking.

Raw onions are a better source of vitamin C, vitamin B1 (Thiamine), vitamin B2 (Riboflavin), vitamin B6 (Pyroxidine), vitamin B9 (Folate), and vitamin E.

However, cooked onions offer a higher amount of vitamin A, vitamin B3 (Niacin), vitamin B5 (Pantothenic acid), and vitamin K.

Raw and cooked onions contain the same amount of vitamin D, and vitamin B12 (Cobalamin).

In the following table, you can easily compare cooked vs raw onions’ vitamins content:

Raw OnionsCooked Onions
Vitamin A01.727 IU
Vitamin C8.2 mg4.491 mg
Vitamin D00
Vitamin B1 (Thiamine)0.046 mg0.036 mg
Vitamin B2 (Riboflavin)0.027 mg0.02 mg
Vitamin B3 (Niacin)0.116 mg0.143 mg
Vitamin B5 (Pantothenic acid)00.098 mg
Vitamin B6 (Pyroxidine)0.12 mg0.111 mg
Vitamin B9 (Folate)19 µg12.955 µg
Vitamin B12 (Cobalamin)00
Vitamin E0.02 mg0.017 mg
Vitamin K0.4 µg0.432 µg

Raw Onions vs Cooked Onions Minerals Content

Most minerals in food, including calcium, phosphorus, magnesium, iron, zinc, iodine, selenium, copper, manganese, chromium, and sodium, are not reduced during cooking.

The exception is potassium, which can be lost in cooking water.

You will get more iron, phosphorus, and potassium by eating onions raw than cooked.

However, if your goal is to increase the intake of calcium, copper, magnesium, manganese, selenium, sodium, and zinc, you should choose cooked over raw onions.

Finally, raw and cooked onions contain virtually the same amount of fluoride.

The table below compares mineral contents in raw and cooked onions, side by side.

Raw Onions (100 grams)Cooked Onions (117 grams)
Calcium17 mg19 mg
Copper0.041 mg0.06 mg
Iron0.24 mg0.21 mg
Magnesium9 mg9.5 mg
Manganese00.13 mg
Phosphorus33 mg30.23 mg
Potassium171 mg143.36 mg
Selenium00.52 µg
Sodium1 mg2.59 mg
Zinc0.17 mg0.18 mg

The Bottom Line

The debate between eating onions raw or cooked has both nutritional and culinary aspects to consider.

While raw onions provide many vitamins and minerals, cooking onions can increase the availability of many of these nutrients.

However, cooking onions can also result in the loss of some micronutrients, mostly water-soluble vitamins.

Both options can be a nutritious addition to a balanced diet, so it is recommended to incorporate both raw and cooked onions into your meals for maximum health benefits.

Ultimately, the decision between raw or cooked onions comes down to individual preferences and dietary goals.

How we ensure this article is accurate?
  1. It's written and or reviewed by an expert.
  2. We cite relevant studies and trusted sources.
  3. It's regularly updated.

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