How Many Calories in One Yellow Onion? | Flavorful & Low-Cal

A medium-sized yellow onion (about 110 grams) contains approximately 45 calories.

Yellow onions are a kitchen staple, adding flavor and depth to countless dishes. Whether sautéed, caramelized, or used raw in salads and sandwiches, they are a versatile ingredient that enhances both savory and sweet recipes. But if you’re counting calories or simply curious about the nutritional content, it’s good to know how many calories are packed into one yellow onion.

In this article, we’ll explore the calorie content of yellow onions, their nutritional benefits, and how they can fit into a healthy diet.

Nutritional Breakdown of a Yellow Onion

A medium-sized yellow onion (approximately 110 grams) contains about 45 calories, making it a very low-calorie food. Most of the calories come from carbohydrates, with very little fat or protein. Here's a detailed nutritional breakdown of a typical yellow onion:

Nutrient

Amount per Medium Onion (110g)

Calories

45

Total Fat

0.1 g

Saturated Fat

0 g

Cholesterol

0 mg

Sodium

2 mg

Carbohydrates

10.3 g

Fiber

1.9 g

Sugars

4.5 g

Protein

1 g

As you can see, yellow onions are incredibly low in calories, with 45 calories coming mostly from the natural sugars and carbohydrates found in the onion. The fiber content is also notable, offering 1.9 grams per medium-sized onion.

Key Nutritional Components of Yellow Onions

  • Carbohydrates: The 10.3 grams of carbohydrates in a medium onion primarily come from natural sugars, such as glucose and fructose, which contribute to the onion’s subtle sweetness.
  • Fiber: Onions are a good source of dietary fiber, with 1.9 grams in a medium-sized onion. This fiber helps support digestive health and can assist in maintaining a feeling of fullness.
  • Sugar: Yellow onions contain about 4.5 grams of sugar, which is mostly natural sugar from the onion itself, not added sugars.
  • Protein: With 1 gram of protein, onions aren't a significant source of this macronutrient but still contribute a small amount.
  • Fat and Cholesterol: Yellow onions are very low in both fat and cholesterol, with 0.1 grams of fat and no cholesterol, making them a heart-healthy choice.

Different Sizes of Yellow Onions and Their Calories

The calorie content of yellow onions can vary slightly depending on the size of the onion. A typical yellow onion can range from small to large, and here's how the calorie content changes based on size:

Size

Approximate Weight

Calories

Small

70 grams

30 calories

Medium

110 grams

45 calories

Large

150 grams

60 calories

If you're cooking with a large onion or using it for a recipe that calls for multiple onions, it's helpful to keep in mind that each onion's calorie count will increase with its size. A small onion contains about 30 calories, while a large onion can have as much as 60 calories.

Health Benefits of Yellow Onions

Despite their low calorie count, yellow onions offer several nutritional benefits that make them a healthy addition to your diet.

1. Rich in Antioxidants

Onions, particularly yellow onions, are packed with antioxidants, which help protect cells from oxidative damage caused by free radicals. Quercetin, a powerful antioxidant found in onions, has been shown to have anti-inflammatory and immune-boosting properties.

2. Supports Digestive Health

The fiber in onions, particularly the soluble fiber known as inulin, can promote healthy digestion by helping to regulate bowel movements and supporting beneficial gut bacteria. Inulin acts as a prebiotic, feeding the good bacteria in the digestive system.

3. Good Source of Vitamin C

Yellow onions provide a modest amount of vitamin C, which is essential for immune function, skin health, and tissue repair. While onions aren't as high in vitamin C as citrus fruits, they still contribute to your daily intake.

4. May Improve Heart Health

Onions have been linked to various heart-health benefits. Their antioxidant properties, as well as their ability to improve blood sugar regulation and reduce inflammation, may help lower the risk of heart disease over time. Some studies suggest that the compounds in onions may also help lower blood pressure.

How to Incorporate Yellow Onions Into Your Diet

Yellow onions are incredibly versatile and can be used in a variety of dishes. Here are a few ideas for incorporating them into your meals:

  • Raw: Slice them thin and add to salads, sandwiches, or burgers for a crunchy, zesty flavor.
  • Sautéed or Caramelized: Sautéing or caramelizing onions can bring out their natural sweetness. These methods are perfect for making sauces, soups, or adding a rich flavor to pasta dishes.
  • Roasted: Roasting onions brings out their deep, savory flavor. They pair well with other roasted vegetables, meats, or grains like quinoa or couscous.
  • Pickled: Pickled onions add a tangy contrast to tacos, burgers, or salads.
  • In Soups and Stews: Onions form the base of many hearty soups and stews, providing essential flavor without adding many calories.

How to Reduce the Calorie Content of Onion-Based Dishes

While onions themselves are very low in calories, dishes that feature onions may contain added ingredients that increase the calorie count. Here are a few ways to reduce calories in onion-based recipes:

  • Use Less Oil: When sautéing or frying onions, use a minimal amount of oil or choose a non-stick pan to reduce added fat and calories.
  • Skip the Butter: Caramelized onions are often made with butter, but you can make them lighter by using olive oil or cooking them in broth or water.
  • Limit High-Calorie Add-ins: If you’re adding onions to a dish, be mindful of high-calorie additions like cheese, cream, or heavy sauces. Opt for lighter, plant-based options when possible.

Conclusion: Are Yellow Onions Worth the Calories?

Yellow onions are a fantastic addition to any diet, offering rich flavor with minimal calories. A medium-sized yellow onion contains just 45 calories, making it an excellent low-calorie option for enhancing the taste of a variety of dishes. In addition to being low in calories, onions are rich in antioxidants, fiber, and vitamin C, which contribute to overall health.

Whether you're using onions as a main ingredient or just a flavorful garnish, they offer a delicious way to add depth to your meals without significantly affecting your calorie count. Given their versatility and nutritional benefits, yellow onions are definitely worth incorporating into your cooking routine.