9 Cooking Mistakes That Can Make Your Food More Toxic

Updated: Jun. 10, 2021

Health experts reveal the cooking habits that can lead to health risks, from cooking with the wrong fats to using low-fat everything.

Woman holding frying pan over table with clean cookware, top view
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Cooking mistakes that can make your food more toxic

When it comes to cooking, some people pride themselves on being a top chef, others burn everything they touch, and the rest fall somewhere in between. No matter where you are on the cooking spectrum, there are mistakes cooks make in the kitchen that can actually make their food less healthy to eat.

To identify these cooking mistakes, we asked food experts to share their tips on the best—and worst—ways to prepare food when it comes to healthy eating. (Also, don’t miss the foods to avoid reheating in a microwave.)

Melting fat - Cooking and baking - of cholesterol meals
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Cooking with the wrong fats

Cook with olive oil—but only for certain foods. Butter is back—but is butter better? And then there’s coconut oil—which comes with a few reasons you shouldn’t overdo it when it comes to cooking. So what are the healthiest fats for cooking? Maggie Michalczyk, RDN, recommends doing your homework before buying a jumbo jug of one particular oil and using it for everything. “These oils have different smoke points—that’s the temperature at which they begin to burn—and once they start smoking, the fat breaks down and they can release harmful free radicals into the air,” she says. Be sure to keep portions of oils in check when cooking. This will prevent additional calories (most serving sizes are two tablespoons). Don’t miss how to cook with the 10 healthiest cooking oils.

TOP VIEW: Human hands pouring olive oil on the frying pan

Overheating healthy oils

Oils with low smoke points are better for salad dressings or adding to already cooked foods—but not for high-temperature cooking. “Certain oils, like olive oil and coconut oil, contain nutritional compounds that can be destroyed when heating to high temperatures above their smoke points,” explains Ben Roche, Michelin-star chef and director of product development at Just. For general cooking at home (sautéing, frying, roasting), he recommends using a neutral oil, like grapeseed or sunflower. For flavoring cold sauces and drizzling over prepared food, he suggests using extra virgin olive oil or flaxseed oil to preserve flavor and nutrition. (You might find this information on cooking oils helpful.)

Fried donuts on a baking sheet. Donuts lie in several layers.
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Frying your food

It might taste downright delicious, but consuming deep-fried food on the regular isn’t good for your health. “The act of frying turns otherwise healthy foods, like vegetables and lean meats, into unhealthy, trans-fat-laden treats,” says Jeanette Kimszal, RDN, founder of Root Nutrition Education & Counseling Services, which helps people with their health and nutrition lifestyle. (Although many countries and regions have reduced or restricted trans fat in food establishments.) If you can’t shake your fried food obsession, Kimszal suggests purchasing an air fryer. This device does not require any oil to cook your food, so you can still enjoy your favorite foods without extra fat that could possibly hurt your health. (Find out if canola oil or vegetable oil is healthier.)

Chicken or turkey poultry meat barbecue grilled burgers for hamburger prepared on bbq smoke grill, close up
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Charring your meat

While raw or undercooked meat can pose health hazards, so can overcooked or charred meats. “Cooking meats above 300°F, which usually results from grilling or pan frying, can form compounds called HCAs (heterocyclic amines) and PAHs (polycyclic aromatic hydrocarbons), that may be harmful to human DNA,” warns Christen Cupples Cooper, EdD, RDN, assistant professor and founding director of the Nutrition and Dietetics Program at the College of Health Professions at Pace University. “Some research suggests that when metabolized, these compounds may activate enzymes linked to cancer risk.” While the research is limited, Cooper believes there’s enough evidence to recommend reducing your exposure to these chemical compounds. “Avoid cooking foods for any length of time over an open flame or hot metal surface, turn meat frequently during cooking, and cut away charred portions of meat,” she says. (Here are the best meats– and three of the worst– for your health.)

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Getting too much salt

If there’s one flavor Americans love in their food, it’s salt. In fact, about 90 percent of people living in the U.S. over the age of two consume too much of the stuff, according to the Centers for Disease Control and Prevention. The 2015–2020 Dietary Guidelines for Americans recommends an upper limit of 2,300 mg of salt per day, which is about a teaspoon; the average adult consumes over 3,400 mg. “In some cases, our taste buds may be desensitized to the flavor of salt,” says Michalczyk. The problem is all the sodium packed into prepackaged foods: A total of 70 percent of the sodium in the average American diet comes from processed food, according to a 2017 study published in the journal Circulation. (Here are some foods that are surprisingly high in sodium.)

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Adding too much sugar

Did you know that the average American consumes over 150 lbs of sugar each year? That’s more than five times the recommended amount. “Desserts are an obvious culprit, but sugar is often hiding in unsuspecting foods, such as dressings, marinades, and sauces,” warns Maya Krampf, founder of Wholesome Yum. “Natural forms of sugar, like honey and maple syrup, are slightly better, but they still spike insulin levels in a similar way as refined sugar.” Instead, she recommends taming your sweet tooth by serving up savory, liberally seasoned dishes when preparing meals and opting for fruit-centric desserts whenever possible. In recipes calling for sugar, Arianne Perry, wellness entrepreneur and co-founder of Sweet Defeat, recommends halving the amount called for. “I do this in baked goods, like banana bread, and no one can taste the difference—it’s so subtle!”

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Relying on processed frozen food dishes for weekday meals

It’s tempting to turn to a frozen meal that promises to be ready for you in just minutes in the microwave. This is especially true after a long, stressful day of work. But oftentimes, these foods contain preservatives and chemicals. Remember that humans have only been exposed to these for a very short time in evolutionary history,” says Krampf. “Not only do processed foods leave less room in your diet for healthier foods, but they are loaded with ingredients like artificial preservatives, refined sugar, and white flour.” Instead, she recommends opting for whole foods, like vegetables, fruits, eggs, and meat whenever possible. And, if you must buy something in a box, choose one with ingredients that you understand. (Here are healthier frozen meals you can feed your kids.)

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Drinking alcohol while cooking

Unless you’re sipping on a full stomach, experts warn against having that glass of wine while stirring your family’s meal. “Drinking on an empty stomach can lead to an unhealthy spike in blood sugar,” says Michalczyk. “Plus you may notice that the longer you wait to eat after the initial drink, the hungrier you will feel, which may lead you to overdo on whatever food you see next.” Or the opposite can happen: Drinking alcohol before a meal might suppress your appetite, causing you to miss out on calories and nutrients your body needs.

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Using “low-fat” everything you can find

There was a time when nutrition experts believed that fat was the enemy. But, thankfully, that time has come and gone. We’ve since learned that there are some fats that are good for your health. For example, avocados and fish are full of good fats (omega-3-fatty acids). Krampf warns that not adding enough fat when cooking is a mistake. “In addition to being an energy source and protection for organs, fat is used in cell membrane function, starts reactions that affect the immune system and metabolism, and allow for absorption of vitamins A, D, E and K,” she says. Next, read about the clear signs you’re not eating enough healthy fats.