The Worst Ways to Prepare Vegetables

You know you need to eat your vegetables, but did you know there’s a right and wrong way to do it? Preparation is key if you want to get the most out of nutrient-dense powerhouses like broccoli and tomatoes, though the answer to the question about the best or worst way to prepare your veggies isn’t as clear-cut as we might like. A particular cooking method “may enhance the availability of one nutrient while degrading another,” Tara Parker-Pope of The New York Times explained. Still, if you’re looking to get more of certain nutrients, you’ll want to have at least some idea of how different cooking methods affect your food. Before you steam, stir-fry, or grill your next plate of veggies, check out this list of some of the worst ways you can prepare them.

1. Boiling cauliflower


Cauliflower |

“Water is not the cook’s best friend when it comes to preparing vegetables,” wrote the authors of a Spanish study looking at how different cooking methods affected the antioxidant activity of 20 different vegetables. Case in point: When boiled, cauliflower, which is high in antioxidants like vitamin C, lost more of its free-radical-fighting properties than almost every other vegetable. Microwaving also reduced cauliflower’s antioxidant properties.

2. Frying zucchini


Zucchini | MYCHELE DANIAU/AFP/Getty Images

Fried zucchini crisps and fritters may be a tasty alternative to snacks like potato chips, but you may not be getting all this veggie’s health benefits when you prepare it that way. Zucchini lost some of its antioxidant properties when it was fried, the Spanish researchers discovered.

3. Stir-frying broccoli

overhead shot of raw broccoli florets

Broccoli |

Stir-frying may be a quick and tasty way to prepare broccoli, but you’ll get the most out of the veggie when you steam it, according to a study conducted by Chinese researchers. That cooking method retains more of broccoli’s nutrients. Other ways of preparing the cruciferous vegetable, including microwaving, boiling, and stir-frying, “caused significant losses of chlorophyll and vitamin C and significant decreases of total soluble proteins and soluble sugars,” according to the study’s authors.

4. Raw tomatoes

Pile of Heirloom Tomatoes

Heirloom tomatoes |

Tomatoes are rich in lycopene, an antioxidant that’s been linked to a lower risk of heart disease, cancer, and other health problems. But simply adding a slice of raw tomato to your sandwich isn’t the best way to eat these veggies. To unlock the power of lycopene in tomatoes, you need to cook them, according to research conducted at Cornell University. We think that’s as good an excuse as any to whip up a homemade tomato sauce for dinner.

5. Raw carrots


Carrots | Photo by Dan Kitwood/Getty Images

Raw versus cooked? Conventional wisdom says you’ll lose nutrients when you boil your vegetables, but that’s not always the case. Cooking carrots actually increases their level of beta-carotene, a study published in the European Journal of Nutrition found. So, while raw baby carrots may still be a healthy snack, you should consider boiling or steaming them if you want to unlock all their nutritional benefits.

6. Boiling eggplant


Eggplant | FRED TANNEAU/AFP/Getty Images

Fried vegetables may actually be good for you, according to results of a Spanish study published in the journal Food Chemistry. The researchers prepared four types of vegetables, including eggplant, three different ways, and found frying in extra-virgin olive oil resulted in higher levels of phenols, antioxidants that might help prevent chronic diseases like cancer and macular degeneration. The levels of phenols were lower in eggplant that had been boiled, either in water or a mix of water and olive oil. Apparently, phenols from the extra-virgin olive oil were transferred to the veggies during the cooking process.

7. Boiling potatoes


Potatoes |

Just say no to boiled potatoes. Why? Potatoes that are baked, rather than boiled, have more resistant starch, a study conducted by researchers from the U.S. Department of Agriculture and the University of Minnesota found. Consuming resistant starch might help regulate blood glucose levels and cause positive changes to the bacteria in your colon. (Also, because our bodies can’t digest resistant starch, foods that contain a lot of it tend to be lower in calories, Prevention explained.) But to get the full benefit, you’ll need to wait a bit: Cold potatoes had more resistant starch than hot ones.

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