Using Onions On A Weight Loss Diet – Benefits And Safety

Effective ways of using this delicious bulb to fight the flab and achieve your ideal weight

Medically reviewed by Kelly McKenzie, Registered Clinical Nutritionist Kelly McKenzie Kelly McKenzieRegistered Clinical Nutritionist linkedin_icon
Written by , MSc (Nutrition), CDE Priyanka Sadhukhan MSc (Nutrition), CDE linkedin_icon Experience: 8 years
Edited by , BA (Literature & Psychology), PG Diploma Arshiya Syeda BA (Literature & Psychology), PG Diploma linkedin_icon Experience: 7 years
Fact-checked by , BTech (Biotechnology), Certified Health & Nutrition Life Coach Sindhu Koganti BTech (Biotechnology), Certified Health & Nutrition Life Coach linkedin_icon Experience: 6 years
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If you have been looking for natural ways to shed some kilos, your search ends here. The solution is right in your kitchen – it is the onion! Onion for weight loss? What? Yes, you heard it right! Onion contains quercetin (a flavonoidi  A kind of polyphenol found in plants that have anti-inflammatory properties and protect cells against oxidative damage. ) that shows promise in boosting metabolism and preventing fat buildup (1), (2).

In this article, we explore how exactly onions can help you in your weight loss journey and the best ways to include them in your diet. Read on!

Nutritional Value Of Onion

Onions offer a powerful blend of essential nutrients and low-calorie content. With a mere 9.34 g of carbohydrates per 100 grams, they can be a tasty addition to your diet without adding excess calories (3). Onions are also rich in potassium (146 mg per 100 grams), which may help support fluid balance and help you maintain a healthy weight. The vitamin C (7.4 mg per 100 grams) found in onions is not only essential for a strong immune system but may also enhance the body’s ability to burn fat during exercise. By incorporating onions into your diet, you not only add flavor but also embrace a natural, nutrient-rich strategy for achieving your weight goals.

Benefits Of Red Onion For Weight Loss

1. Low In Calories

Onions are extremely low in calories. 1 cup (160 g) of chopped onion provides 64 kcal of energy (3).

A low-calorie diet with increased fruit and vegetable intake is effective in aiding weight loss (4).

2. A Fairly Good Source Of Fibre

1 cup of onion contains 3 g of fiber. Thus, it adds bulk to your meals (2).

The soluble viscous fiber found in onions improves satiety (the feeling of fullness) and helps you avoid extra calorie intake, thus aiding weight loss (5).

3. The Anti-Obesity Effect Of Quercetin

Onions are rich in a plant compound called quercetin. This flavonoid possesses an Anti-Obesity property (6), (7).

A study conducted on high fat-fed rats found that the quercetin-rich onion peel may have an anti-obesity effect (8). Also it might help in stabilizing cholesterol, blood sugar. and even lowering triglycerides. However, more research is required to substantiate this claim.

Now that you know all about the relationship between onions and weight loss, let’s check out three ways to incorporate them into your diet.

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Avoid onions in your diet if you are on blood thinners. Onions slow down blood clotting, and taking them with blood thinners may increase the risk of bruises and bleeding.

How To Use Onions For Weight Loss

1. Onion Juice

Onion juice for weight loss
Image: Shutterstock

Drinking onion juice is the best way to add this vegetable to your diet. Frying it can destroy the nutrients. Therefore, to reap all its health benefits, drink onion juice. Here’s the best way to prepare onion juice for weight loss.

Preparation Time – 5 min; Cooking Time – 7 min; Serves – 2

  • 1 bulb of fresh white onion
  • 3 cups of water

How To Prepare

  1. Remove the skin of the onion and slice it.
  2. Add a cup of water to a saucepan and bring it to a boil.
  3. After 4 minutes, remove it from flame and transfer it to a blender.
  4. Blend it well and add two more cups of water.
  5. Pour the onion juice into a glass and drink it.

2. Onion Soup

Onion soup for weight loss
Image: Shutterstock

Soups are incredible when it comes to weight loss. They fill you up and are loaded with nutrition. You can have soup for lunch or dinner. Here’s a great way to prepare onion soup that tastes amazing and will help you lose weight.

Preparation Time – 15 min; Cooking Time – 15 min; Serves – 2

  • 4-5 large red onions, peeled and chopped
  • 1 cup chopped tomato
  • 1 cups shredded cabbage
  • 3 cups vegetable or chicken stock
  • 3 cloves of minced garlic
  • ½ inch grated ginger root
  • ¼ teaspoon black pepper
  • 1 teaspoon olive oil
  • Salt to taste
  • A handful of cilantro to garnish
How To Prepare
  1. Add olive oil to a soup pot.
  2. Add the ginger and garlic and saute for 2 minutes.
  3. Add the onions and veggies. Stir and cook for 30 seconds.
  4. Now, add the vegetable or chicken stock.
  5. Add black pepper and salt. Stir and cover. Cook for 10-15 minutes.
  6. Transfer the soup to a bowl and garnish it with cilantro.
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Excessive onion consumption may cause digestive issues. Therefore, limit your intake to a cup (80-120 g) daily.

3. Raw Onion

No surprise that if boiled onions can be so healthy, raw onions are even better. The phytonutrientsi  Natural compounds found in plants that help them fight unwanted bacteria and stay healthy. Also known as phytochemicals. in onions don’t undergo heat-induced degradation when you eat them raw. So, you get the best of the nutrients present in onions, which can help you lose weight effectively. Here’s how we recommend you eat raw onion for weight loss.

Preparation Time – 5 min; Cooking Time – 5 min; Serves – 2

  • 1 medium-sized red onion, sliced
  • 1 lime wedge
  • A pinch of pink Himalayan salt
How To Prepare 
  1. Toss the sliced raw onion into a bowl.
  2. Squeeze the juice of lime on the onion slices.
  3. Sprinkle a little pink Himalayan salt.
  4. Eat it as a side for lunch or dinner.

Those were the three best ways to consume onion for fat loss. Now, here are a few more onion recipes for weight loss that will keep you coming back for more! Take a look.

Onion Recipes For Weight Loss

1. Pomegranate Onions

Pomegranate and onion salad for weight loss
Image: Shutterstock

Pomegranate onions are delicious and can be enjoyed with non-vegetarian or vegetarian food. It includes ingredients that promote weight loss. This recipe is super easy to make.

Prep Time – 15 min; Cooking Time – 10 min; Serves – 6

  • 4 red onions, peeled and quartered
  • 4 tablespoons pomegranate molasses
  • 1 tablespoon tahini
  • 2 tablespoons olive oil
  • 4 tablespoons pomegranate juice
  • A pinch of freshly ground black pepper
  • Salt to taste
  • 1 tablespoon chopped parsley
How To Prepare
  1. Toss the onions in olive oil and skewer them.
  2. Place them on a griller.
  3. In a bowl, mix pomegranate molasses, pomegranate juice, black pepper, a pinch of salt, and tahini.
  4. Remove the onions from the skewer and drizzle the pomegranate molasses mixture.
  5. Garnish with parsley.

2. Baked Onion, Sweet Potato, Sausage, And Bell Peppers

Baked onions for weight loss
Image: Shutterstock

If you are on a weight-loss mission, you must watch what you eat. Consume wholesome food and cook it the right way to reap all the goodness of each vegetable. Here’s how to prepare baked onion with veggies for weight loss.

Prep Time – 20 min; Cooking Time – 25 min; Serves – 2

  • ½ cup sliced sausage
  • 1 cup sliced onion wedges
  • ½ cup sweet potato wedges
  • ½ cup bell pepper wedges
  • 4 tablespoons olive oil
  • 4 tablespoons white wine
  • ¼ cup chicken stock
  • ½ teaspoon dried rosemary
  • ½ teaspoon black pepper
  • Salt to taste
How To Prepare
  1. Preheat the oven to 400 degrees F.
  2. Heat 2 teaspoons of olive oil in a skillet and cook the sausages until they turn brown.
  3. Now, add all the veggies to a baking dish and drizzle a generous amount of olive oil.
  4. Add the chicken stock and season it with salt, pepper, and dried rosemary.
  5. Add the cooked sausage and bake it for 25-30 minutes.

3. Zucchini And Onions In Teriyaki Sauce

Delicious zucchini and onions in teriyaki sauce for weight loss
Image: Shutterstock

This yummy dish is full of flavor and great for weight loss. It is loaded with antioxidants and dietary fiber, which will help prevent fat absorption and improve bowel movement. Here’s how to prepare it.

How To Prepare Zucchini & Onions In Teriyaki Sauce

Prep Time – 20 min; Cooking Time – 25 min; Serves – 2

  • 1 large onion, thinly sliced
  • 1 ½ cup zucchini strips
  • 3 tablespoons olive oil
  • 2 tablespoons teriyaki sauce
  • 1 tablespoon soy sauce
  • 1 teaspoon sesame seeds
  • ¼ teaspoon ground black pepper
  • Salt, if required
How To Prepare
  1. Heat olive oil in a frying pan and saute the onions.
  2. Now add the zucchini, salt, pepper, teriyaki sauce, and soy sauce. Cook it until the zucchini becomes soft and cooked.
  3. Check if salt is required and add some if needed.
  4. Transfer it to a plate and garnish with sesame seeds.

4. Caramelized Onions And Red Chard Salad

Caramelized onions in red chard sauce for weight loss
Image: Istock

Salads are one of the best things you can have when you want to lose weight. They don’t weigh you down and support digestion. So, here’s a delicious onion salad recipe for you to try.

Prep Time – 5 min; Cooking Time – 7 min; Serves – 2

  • 1 large white onion, chopped
  • 1 cup red chard, chopped
  • 2 tablespoons olive oil
  • ¼ cup sun-dried tomatoes
  • 2 tablespoons lime juice
  • 1 teaspoon brown sugar
  • 7-8 slices of pickled onions
  • ½ teaspoon chili flakes
  • Salt to taste
How To Prepare
  1. Add olive oil, lime juice, brown sugar, chili flakes, and a pinch of salt in a bowl and mix well.
  2. Add onions, red chard, pickled olives, and sun-dried tomatoes in a large bowl.
  3. Drizzle the dressing and give it a quick toss.

These four onion recipes will help keep your hunger at bay and aid weight loss. You can also try creating your own recipes to fill your tummy and satiate your taste buds, while being nutrition rich as well.

Other Health Benefits Of Onion

  • It may help lower blood sugar (9).
  • It may improve heart health (10).
  • It helps strengthen the bones (11).
  • It is prebiotici  Food compounds that promote the growth of good bacteria, fungi, and other microorganisms essential for a healthy gut. that supports the digestive system and improves gut health (12).
  • The quercetin in onion prevents inflammation and clears nasal congestion (13).
  • Onion extract may have an inhibitory effect on the immune response (14).
  • It may promote respiratory health (15).
  • The prebiotics in onion improves sleep (16).

Though onions aid weight loss and are generally good for your health, you must follow some precautions to stay on the safe side. Check them out below.


  • Excess onion consumption may cause gastric irritation. Therefore, drink enough water after consuming onion and other sulfur-rich vegetables.
  • Eating too much onion may cause heartburn.
  • Onion consumption causes bad breath. To get rid of that, chew 2-3 mint leaves or peppermint gum. You can also brush your teeth and use mouthwash to get rid of onion breath.

Infographic: Different Ways Of Using Onion For Weight Loss

Onions are low in calories and rich in dietary fiber and quercetin, which help boost metabolism, prevent fat build-up, and help with weight loss. While there are many other benefits of onions, they seem to be popular for their use in weight loss. In the following infographic, we have discussed the different ways you can use onions to achieve weight loss. Take a look.

 3 benefits of caprylic acid & major side effects (infographic)

Illustration: StyleCraze Design Team

In short, you can use onions for weight loss. Red onions, in particular, are low in calories, high in fiber, and have an anti-obesity property thanks to quercetin. You can add onion to your food, drink onion juice, or eat it raw to gain its weight-reducing benefits. Scroll up to have another look at some exciting and healthy onion recipes.

Consuming onion alone will not help you shed pounds. You should also exercise, stay active, drink water, and live a healthy lifestyle to stay in shape. Eating too much onion could lead to serious side effects, like gastric issues. Consult a nutritionist or dietician to add onion to your diet in proper amounts.

Frequently Asked Questions

Do onions increase metabolism?

Onion juice and onion peel help boost metabolism. So, it is always suggested to include onions in your diet.

Is it good to eat onions every day?

Yes, it is good to eat onions every day. However, their over consumption may cause gastric irritation and heartburn. Limit your portions for the best results.

White or red – which onion is good for weight loss?

Red onions are good for weight loss. They are particularly high in quercetin, which has been found to exhibit Anti-Obesity effects in rats.

Is spring onion good for weight loss?

Spring onion or green onion stimulates satiety in the brain and is an effective fat burner. You can use spring onion in onion soup to augment its fat-burning properties.

What is the best time to eat onion?

There is no recommended best time for consuming onions. You can enjoy them at any time of the day.

Do onions cause gas?

Possibly. Onions contain simple sugars like fructose, which breaks down during digestion, leading to gas formation.

Key Takeaways

  • Red onions contain an antioxidant called quercetin that helps in weight management in animal models.
  • It is also a rich source of dietary fiber, which promotes satiety and promotes bowel regularity.
  • Consuming onion juice or soup is a great way of getting the required nutrients and helping you lose weight.
  • Daily consumption of onions may also improve sleep quality and lower blood sugar.
  • Excessive consumption may cause gastrointestinal distress, bad breath, or heartburn.
onion for weight loss

Image: Stable Diffusion/StyleCraze Design Team


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  1. Chen, Shuang, et al. “Therapeutic effects of quercetin on inflammation, obesity, and type 2 diabetes.” Mediators of inflammation 2016 (2016).
  2. Marrelli, Mariangela, et al. “Biological properties and bioactive components of Allium cepa L.: Focus on potential benefits in the treatment of obesity and related comorbidities.” Molecules 24.1 (2019): 119.
  3. US Department of Agriculture, Agricultural Research Service. “Nutritive value of onions, raw.”
  4. Champagne, Catherine M., et al. “Dietary intakes associated with successful weight loss and maintenance during the Weight Loss Maintenance trial.” Journal of the American Dietetic Association 111.12 (2011): 1826-1835.
  5. Slavin, J., and H. Green. “Dietary fibre and satiety.” Nutrition Bulletin 32 (2007): 32-42.
  6. Zhao, Yueshui, et al. “The beneficial effects of quercetin, curcumin, and resveratrol in obesity.” Oxidative medicine and cellular longevity 2017 (2017).
  7. Henagan, T. M., et al. “In vivo effects of dietary quercetin and quercetin-rich red onion extract on skeletal muscle mitochondria, metabolism, and insulin sensitivity.” Genes & nutrition 10.1 (2015): 2.
  8. Moon, Jiyoung, et al. “Antiobesity effects of quercetin-rich onion peel extract on the differentiation of 3T3-L1 preadipocytes and the adipogenesis in high fat-fed rats.” Food and chemical toxicology 58 (2013): 347-354.
  9. Preliminary Study of the Clinical Hypoglycemic Effects of Allium cepa (Red Onion) in Type 1 and Type 2 Diabetic Patients,hours%20(P%20%3D%200.005).
  10. González-Peña, Diana, et al. “New insights into the effects of onion consumption on lipid mediators using a diet-induced model of hypercholesterolemia.” Redox biology 11 (2017): 205-212.
  11. Matheson, Eric M., Arch G. Mainous III, and Mark A. Carnemolla. “The association between onion consumption and bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older.” Menopause 16.4 (2009): 756-759.
  12. Slavin, Joanne. “Fiber and prebiotics: mechanisms and health benefits.” Nutrients 5.4 (2013): 1417-1435.
  13. Chang, Jung Hyun, et al. “Dietary polyphenols affect MUC5AC expression and ciliary movement in respiratory cells and nasal mucosa.” American journal of rhinology & allergy 24.2 (2010): e59-e62.
  14. Chisty, M. M., et al. “Effect of onion extract on immune response in rabbits.” Bangladesh Medical Research Council Bulletin 22.2 (1996): 81-85.
  15. Jaber, Raja. “Respiratory and allergic diseases: from upper respiratory tract infections to asthma.” Primary Care: Clinics in Office Practice 29.2 (2002): 231-261.
  16. Thompson, Robert S., et al. “Dietary prebiotics and bioactive milk fractions improve NREM sleep, enhance REM sleep rebound and attenuate the stress-induced decrease in diurnal temperature and gut microbial alpha diversity.” Frontiers in behavioral neuroscience 10 (2017): 240.
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Kelly McKenzie is a Registered Clinical Nutritionist with 3 years of experience, based in Auckland, New Zealand. She is the founder of All About Nutrition, a nutrition consultancy that takes a holistic approach to their clients health and wellbeing.

Read full bio of Kelly McKenzie
Priyanka Sadhukhan
Priyanka SadhukhanNutritionist, CDE
Priyanka is a nutritionist and a Certified Diabetes Educator. She has over 8 years of experience in nutrition and dietetics with a strong research background. She is passionate about science and how it can be applied to one’s daily lifestyle.

Read full bio of Priyanka Sadhukhan
Arshiya Syeda
Arshiya SyedaSenior Editor
Arshiya Syeda is a senior editor at StyleCraze with 7 years of experience. Prior to that, she was a content writer and combined her writing and research skills to write over 200 high-performing articles on hairstyles, hair care, and skin care.

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Sindhu Koganti
Sindhu KogantiSenior Health & Wellness Writer
Sindhu Koganti is a Certified Health and Nutrition Life Coach and has over 6 years of experience in writing on health and wellness topics. She has a bachelor’s degree in biotechnology from Acharya Nagarjuna University, Guntur, and a diploma in nutrition from Fab Academy.

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