Sound nutrition, as we all know by now, is key to good health. So we strive for diets rich in the good stuff (like vegetables, fruits, and whole grains) and low in the not-so-good stuff (like bacon and heavy cream). But a growing body of evidence shows that what's on your plate isn't the only factor in good nutrition. How you prepare it matters, too.
During the past several decades, food scientists have uncovered the effects of various cooking methods on our health. In general, the longer and hotter you cook, the more carcinogenic compounds you create -- particularly with meat. Overcooking fats and oils can also produce toxins. "Any type of cooking that really turns up the heat changes the food's structure, which ultimately changes the effects on your body," explains Kathie Swift, R.D., nutrition director of the UltraWellness Center in Lenox, Massachusetts.
That's hardly appetizing news. Fortunately, there are plenty of cooking methods that benefit your taste buds along with the rest of your body. You don't need a nutrition degree or a spot on "Top Chef" to prepare delicious, good-for-you food, either. "Eating healthfully and cooking healthfully go hand in hand," says Joy Kettler Gurgevich, a behavioral nutritionist based in Tucson, Arizona. So grab your favorite vegetables, fish, or lean cuts of meat and use our culinary cheat sheet to plan your next meal.
THE HEALTHIEST BETS
When you cook, keep things simple. "The healthiest methods alter food slightly to enhance the taste and texture and make it easier to digest," says Gurgevich. No matter which of these techniques you use, experiment with herbs and spices, which add flavor and fragrance along with health-boosting phytochemicals.
Not just for breads and desserts, baking is a healthy way to prepare seafood, lasagna, fruit, vegetables, and seasoned tofu, too. Avoid using extra oil or fat to keep it moist by baking meat in covered cookware with a little of its own juices. Roasting, a related technique that uses higher temperatures (usually 300 degrees and above), is a good option for starchy root vegetables such as sweet potatoes and winter squash and lean cuts of meat; avoid overcooking.
In this simple technique, food cooks in a metal or bamboo basket over simmering water. The short cook time and the fact that the food doesn't touch the water keeps nutrient levels high. It's a great choice for vegetables and fish; add flavor with herbs and spices after cooking.
This traditional Asian method lets you cook vegetables and soy quickly at high temperatures with small amounts of oil in a wok or large fry pan. The result? Flavorful, nutrient-rich dishes with a crisp yet tender texture. To maximize the health factor, use cold-pressed canola or peanut oil and stop cooking before the oil smokes, an indication that its molecules are breaking down, potentially becoming toxic and carcinogenic. "If oil starts to smoke," says Gurgevich, "throw it out and begin again."
Lightly sauteing tofu, chicken, fish, and vegetables is a great way to help food retain its nutrients -- and produces tasty results. Keep the stove temperature at medium so the oil lightly sizzles. When using heart-healthy olive oil, which has a low smoke point, Gurgevich suggests a combination of sauteing and steaming: Briefly saute vegetables, then add a splash of water to the pan. Put on a lid, and let the veggies cook until they're tender yet crisp. Remove the lid near the end of cooking and let excess water evaporate.
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PROCEED WITH CAUTION
Knowing which cooking methods are less than sound -- and why -- can help you make healthy substitutions. Don't worry -- you won't have to jettison all of your favorite techniques. Some cooking methods lend themselves to certain types of food over others. And in some cases, you can take steps to lessen the damage (without sacrificing flavor).
Sounds healthy, but studies show that boiling vegetables leaches nutrients into the water -- and down the drain. If you're making corn on the cob or broccoli, for example, grill or steam it to retain its healthy compounds. You can even steam potatoes for mashing rather than boil them. But for soups, says Gurgevich, boiling veggies at a low temperature is healthy; the broth captures the nutrients.
As with grilling, broiling meat until well-done creates HCAs, says Karen Collins, R.D., nutrition adviser to the American Institute for Cancer Research. If you broil animal protein, do so until it's cooked through to about medium -- not charred -- to reduce HCA formation, she advises. Cooking this way on a raised broiler pan also allows fat to drip off the meat, lowering the fat and calorie content, although it has no effect on HCA levels.
At the end of a long day, it's tempting to zap something in the microwave. Although there's mixed evidence about the effects of this method, research suggests that it's not the most nutritious choice for some foods; one study found that microwaving broccoli in water destroyed up to 97 percent of certain antioxidants. To be on the safe side, Gurgevich recommends defrosting in the fridge rather than the microwave. And avoid microwaving in plastic containers or covering the food with plastic wrap: The heat can drive unhealthy chemicals from the plastic into food.
That crispy, blackened steak may look and taste great, but charring animal foods (whether in a gas or charcoal grill) has been shown to create chemicals called heterocyclic amines (HCAs) and advanced glycation end products (AGEs), which appear to increase the risk of cancer, cardiovascular disease, diabetes, Alzheimer's disease, and other chronic conditions. In fact, a recent study in the Journal of Gerontology reported that the more food-related AGEs people had in their blood, the higher their signs of inflammation.
If you can't resist the lure of the grill, at least move lean meat or fish to the sidelines and make vegetables the focus: "HCAs don't form in grilled vegetables, only in animal protein," explains Collins. (Black char on vegetables should be avoided, however, as it may contain other harmful substances.) Flip meat every few minutes to avoid prolonged contact with the most intense heat, and marinate food first, advises Swift. Research shows that soaking meat in marinades that contain rosemary, thyme, garlic, and other antioxidant-rich herbs before grilling can lower HCA formation significantly.
You don't have to avoid these techniques altogether, but the unhealthy changes they create in food make them best reserved for occasional treats.
When food is submerged in hot oil (think doughnuts, fries, and chips), the food cooks fast, but the process adds too much fat, often including unhealthy trans fats.
Although this cooking method calls for less oil than deep-frying, it isn't much better. When used for seafood, poultry, and meat, it can produce more HCAs than healthier methods such as baking, says Collins.
This baked chicken is just as addictively crispy and delicious as any deep-fried version.