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Red Onion (raw): Calorie Count & Nutritional Breakdown

Red Onion (raw) contains 40 kcal per 100g, with 1.1g of protein, 9.3g of carbohydrates, and 0.1g of fat. A low-fat option at just 0.1g of fat per 100g. It is low in calories, making it suitable for calorie-controlled diets. It is suitable for vegans.

  • Allergens: None of the major allergens
  • Dietary: Paleo, Halal, Kosher, Vegan, Vegetarian
  • Key Micronutrients (per 100g): Iron 0.21mg, Calcium 23.0mg, Vitamin C 7.4mg
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Nutritional Overview

Red Onion (raw) is a natural whole food enjoyed worldwide as part of a balanced diet. Per 100g serving, it provides 40 kcal of energy, 1.1g of protein, 9.3g of carbohydrates, and 0.1g of fat.

With just 0.1g of fat per 100g, it meets the UK/EU "low fat" nutrition-claim threshold. This makes it a lighter option for those monitoring their fat intake as part of a heart-healthy or weight-management diet.

With only 4.2g of sugar per 100g, it meets the UK/EU "low sugar" nutrition-claim threshold. This makes it a suitable choice for those reducing their sugar intake as part of a balanced diet.

Each 100g serving provides 1.7g of dietary fibre per 100g, meeting the UK/EU "high fibre" nutrition-claim threshold. The UK government recommends 30g of fibre per day for adults. Adequate fibre intake supports healthy digestion, helps regulate blood sugar levels, and may reduce the risk of heart disease and bowel cancer.

At just 40 kcal and 0.1g of fat per 100g, this meets the UK/EU "low calorie" and "low fat" nutrition-claim thresholds, a genuine low-calorie, low-fat option that can support weight management goals. It can be included generously in calorie-controlled meals without significantly increasing overall energy intake.

Each 100g serving contains 0.00g of salt, meeting the UK/EU "low salt" nutrition-claim threshold. The NHS recommends adults consume no more than 6g of salt per day, so choosing lower-salt foods like this one makes it easier to stay within that limit and supports healthy blood pressure.

Red Onion (raw) is suitable for vegan, halal and kosher diets, making it a versatile choice for households with mixed dietary requirements. Turning Red Onion (raw) into a real number rather than a guess takes seconds. Our food calculator logs its 40 kcal per 100g instantly.

Frequently Asked Questions

How many calories are in Red Onion (raw)?

Red Onion (raw) contains 40 kcal per 100g, which is approximately 2% of the recommended daily intake of 2,000 kcal for an average adult. This meets the UK/EU "low calorie" nutrition-claim threshold.

Is Red Onion (raw) a good source of protein?

Red Onion (raw) contains 1.1g of protein per 100g, which is relatively low. To increase your protein intake, consider pairing it with Pork Crackling, Dried Halibut (Greenlandic), Pea Protein Powder, or other protein-rich foods.

Is Red Onion (raw) low in fat?

Yes, Red Onion (raw) contains only 0.1g of fat per 100g, meeting the UK/EU "low fat" nutrition-claim threshold. This makes it a suitable choice for those watching their fat intake.

Is Red Onion (raw) low in sugar?

Yes, Red Onion (raw) has only 4.2g of sugar per 100g, meeting the UK/EU "low sugar" nutrition-claim threshold.

Is Red Onion (raw) low in salt?

Yes, Red Onion (raw) contains only 0.00g of salt per 100g, meeting the UK/EU "low salt" nutrition-claim threshold. This makes it a suitable choice for those managing their sodium intake as part of a heart-healthy diet.

Is Red Onion (raw) high in fibre?

Yes, Red Onion (raw) provides 1.7g of dietary fibre per 100g, meeting the UK/EU "high fibre" nutrition-claim threshold. The UK government recommends 30g of fibre per day for adults.

Is Red Onion (raw) suitable for vegans?

Yes, Red Onion (raw) is suitable for a vegan diet as it contains no animal-derived ingredients. It provides 40 kcal and 1.1g of protein per 100g.

Is Red Onion (raw) free from major allergens?

Red Onion (raw) does not contain any of the 14 major allergens recognised under UK food law. However, cross-contamination during manufacturing is always possible; always check the packaging for 'may contain' warnings.

Is Red Onion (raw) good for weight loss?

With only 40 kcal and 0.1g of fat per 100g, Red Onion (raw) meets the UK/EU "low calorie" and "low fat" nutrition-claim thresholds, a genuine low-calorie, low-fat food that can be a helpful part of a calorie-controlled diet for weight management.

Sources & References

  1. British Nutrition Foundation — UK nutrition science and education
  2. McCance & Widdowson's Composition of Foods — UK food composition tables
  3. USDA FoodData Central — US Department of Agriculture food composition database
  4. NHS Eat Well — UK National Health Service dietary guidance
  5. Food Standards Agency (FSA) — UK food labelling regulations and traffic-light nutrition guidelines
  6. British Dietetic Association (BDA) — UK registered dietitians and evidence-based food fact sheets

Nutritional values are per 100g unless otherwise stated and are provided for general information only. Not a substitute for professional dietary or medical advice. If you have a health condition, allergy, or are pregnant, consult a qualified healthcare professional. Values may vary depending on brand, preparation method, and serving size.

Lower Calorie Alternatives

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