Many of my clients assume they should be eating fresh, raw produce to reap the most health perks possible. But the reality is, several studies have debunked conventional wisdom about the best ways to store, prep and cook fruits and veggies. Check out these science-backed tips for getting the most nutritional bang per bite from seven of your favorites.
Store watermelon at room temperature
After bringing home a watermelon, many people will stick it in the refrigerator. But according to research from the U.S. Department of Agriculture, keeping it out of the fridge can significantly boost the potency of its antioxidants and other nutrients. The study found that after watermelon was picked and stored at room temp, levels of the protective phytochemical lycopene increased by up to 40%, while levels of beta-carotene rose by nearly 140%.
In contrast, the study found that when other types of melons were chilled, their nutrient levels remained about the same. To optimize the longevity of your melons however, the best temp to store them at is a cool 55 degrees. A whole melon will last up to three weeks at that temperature, versus one week in the refrigerator. (Once you slice the melon, leftovers should go in the fridge.)
I enjoy cooking broccoli in a variety of ways, including stir-frying, grilling, and sautéing. But one classic study published in the Journal of the Science of Food and Agriculture found that to preserve its nutrients, steaming may be the very best method.
Researchers compared how boiling, steaming, and microwaving impacted the total flavonoid antioxidant levels of broccoli, and found that steaming had a minimal effect. (Meanwhile microwaving diminished levels by up to 97%, and boiling caused a 66% loss.)
To up the appeal of steamed broccoli, toss it with a healthy, flavorful coating, like a bit of sundried tomato pesto, olive tapenade or tahini. You could also top it with a nut-based sauce, like my favorite—warmed almond butter seasoned with a bit of fresh grated ginger, minced garlic and crushed red pepper.
Cook and then chop carrots
I love carrots, but I generally prefer them cooked over raw. As it turns out, that’s a good thing, since cooking them significantly boosts their levels of beta-carotene. But be conscious of your process: Research done at Newcastle University found that if carrots are boiled and then chopped, their anti-cancer properties are 25% higher. That’s because cooking them whole helps lock in their nutrients. If you chop first, you increase the veggie’s surface area, while allows more nutrients to leach out into the water as the cook.
The study also found that cooking before chopping preserves more natural flavor. When 100 people were asked to wear a blindfold and compare the carrots, more than 80% rated those that were cut after cooking as tastier.
Let pears get super ripe
Not all fruits continue to ripen after they’ve been harvested, but pears do. And research from the University of Innsbruck found that allowing pears to really ripen increases levels of certain antioxidants. If you purchase pears that are firm, store them at room temperature in a fruit bowl. To speed up the process, put them next to bananas, which produce an ethylene gas that accelerates ripening. To check if your pear is ready to eat, press on the neck. If it gives, it’s ripe.
Pair leafy greens with good fat
In one study from Ohio State, researchers examined the absorption of several key antioxidants when men and women ate veggies with or without avocado. When lettuce and spinach were paired with the healthy fat, subjects absorbed over eight times more alpha-carotene and 13 times more beta-carotene (which both help fight cancer and heart disease), along with four times more lutein (a nutrient linked to eye health). So whether you whip veggies into a smoothie, toss them on a salad, or cook up some leafy greens, be sure to add a good fat (think avocado, EVOO, nuts or seeds) to get the most nutritional benefits.
Stock up on frozen blueberries
Fresh berries are fantastic. But unfortunately, you can’t get high-quality produce year-round, and that’s when frozen berries can be ideal.
In a study from Leatherhead Food Research, scientists tested the nutrient levels in produce that had been sitting in a fridge for three days, compared to their frozen equivalents. Surprisingly, more nutrients were found in the frozen samples. In fact, in two out of three cases, frozen produce packed higher levels of antioxidants, including polyphenols, anthocyanins, lutein and beta-carotene. The conclusion: Freezing fruits and veggies doesn’t make them inferior. It actually helps them retain vital nutrients.
Let garlic sit after you crush it
If you enjoy cooking with garlic, use this tip to make it even healthier: After crushing, let the garlic “rest” for a full 10 minutes. Research shows that this step helps the garlic retain more of its anti-cancer power than when you cook it immediately. Why? Crushing garlic releases an enzyme that’s otherwise trapped in the cells of the plant. This enzyme, which helps boost levels of other health-promoting compounds, requires 10 minutes to peak. So set a timer let your garlic do its thing.
Cynthia Sass is a nutritionist and registered dietitian with master’s degrees in both nutrition science and public health. Frequently seen on national TV, she’s Health’s contributing nutrition editor, and privately counsels clients in New York, Los Angeles, and long distance. Cynthia is currently the sports nutrition consultant to the New York Yankees, previously consulted for three other professional sports teams, and is board certified as a specialist in sports dietetics. Sass is a three-time New York Times best-selling author, and her newest book is Slim Down Now: Shed Pounds and Inches with Real Food, Real Fast. Connect with her on Facebook, Twitter and Pinterest.