Onions are usually the supporting character in a dish, not the main event. So it’s natural to have questions when you see people cooking and devouring whole onions on TikTok in the name of taste.
Onion boils are all over social media right now, and even creators who post about them are surprised by how much they’ve taken off. “I can’t believe how much you guys love onion boils,” said @hannahsfruity in one post, while demonstrating how to make her onion boil recipe.
Some people make the onion boil as a main dish, while others serve it alongside other foods, like seafood or steak. Naturally, there’s a wide variety of onion boil recipes that have taken off, including cheesy onion boils and onion boils with a range of sauces and seasonings.
While onion boils look delicious, plenty of people have concerns about whether it’s actually safe and healthy to eat this much onion in one sitting. We tapped three nutritionists to find out.
Experts Featured in This Article:
Scott Keatley, RD, is a registered dietitian-nutritionist, fellow of the Academy of Nutrition and Dietetics, and co-owner of Keatley Medical Nutrition Therapy.
Jessica Cording, RD, is a nutritionist and author of “The Little Book of Game-Changers.”
Keri Gans, RD, is a registered dietitian-nutritionistand author of “The Small Change Diet.”
What Is an Onion Boil?
Recipes vary, but an onion boil generally involves peeling a whole onion, removing some of the core, and then pouring in a mixture of butter and seasoning. The whole thing is then wrapped in foil and put in the oven for up to an hour, until the onion is tender.
Is It OK to Eat a Whole Onion?
It’s “absolutely” OK to eat a whole onion, says Scott Keatley, RD, co-owner of Keatley Medical Nutrition Therapy. That includes the main bulb, stem, and the roots, if they appeal to you, he says.
“Onions offer a lot of nutrients, antioxidants, and prebiotic fibers,” says Jessica Cording, RD, author of “The Little Book of Game-Changers.” “They’re pretty low in calories and not super high in carbs. I’m a big fan of onions.”
If you have digestive issues, eating a whole onion may not be right for you, says Keri Gans, RD, author of “The Small Change Diet.” But otherwise “it is probably OK to eat a whole one,” she says.
Cording just recommends being aware of your portion size. “I wouldn’t eat an onion the size of your head, but a medium onion would be fine,” she says.
Benefits of Eating a Whole Onion
There are actually a lot of potential benefits to keep in mind. Onions are “rich in antioxidants, especially quercetin, which has anti-inflammatory benefits,” Keatley says. “You’ll get a dose of vitamin C, vitamin B6, folate, potassium, and a variety of phytochemicals beneficial for heart health,” he adds.
Onions are also prebiotics, which are food for postbiotics (good bacteria in your gut). As a result, they may help balance the microbiome in your gut and boost your digestive health, Gans says.
“Onions also contain sulfur compounds with antibacterial properties, which can help combat oral bacteria that contribute to gum disease and tooth decay,” Keatley says.
Side Effects of Eating a Whole Onion
Eating a whole onion isn’t for everyone, and it can cause some digestive discomfort. “The biggest side effects would probably be gas and bloating, as onions contain fructans, a type of carbohydrate that can be hard for some people to digest,” Keatley says. “For those with irritable bowel syndrome, large amounts of onion might cause some discomfort.”
Because of the potential for gastric issues, Cording suggests that you try a few bites first and see how you feel before you eat the whole onion. It’s also a good idea to be aware of the kind of sauce you’re using to cook your onion boil, since many onion boil recipes use a lot of butter and oil. “I would encourage using something that is low in sugar and to be mindful of additives,” Cording says. “You don’t need a heavy duty, high sugar sauce full of additives.”
Is Boiled Onion Good For You?
It can be, but there are a few things to keep in mind here. “The longer you boil an onion, or almost any vegetable, the more nutrients you lose,” Gans says. “But keep in mind, if you also add a large amount of butter, as in the TikTok video, you are also adding saturated fat which has been associated with an increased risk of heart disease and certain cancers.”
But a boiled onion is “still nutrient-rich,” Keatley says. “While some water-soluble vitamins like vitamin C can be lost during boiling, onions retain a lot of their beneficial compounds even after cooking,” he continues. Cooking onions also makes them easier to digest, which may lower the risk of digestive issues in some people, he says.
Overall, if you want to try the onion boil trend, Gans says you should be just fine to go for it. Her advice: “Go light on the butter in order to not undermine their health benefits.”
Korin Miller is a writer specializing in general wellness, health, and lifestyle trends. Her work has appeared in Women’s Health, Self, Health, Forbes, and more.
