Raw vs. cooked: Does it matter for nutrition’s sake?

On Nutrition

If I had a nickel for every time someone asked me whether it’s better to eat vegetables cooked or raw, I would be able to buy a lot of broccoli. Which I would eat both cooked and raw. Much like the answer to the question, “When’s the best time to exercise?” is “The time when you’ll actually do it,” the best way to eat vegetables is the way that you actually enjoy eating them.

It’s true that we get more nutrition from certain vegetables when they are raw, and others when they are cooked. But don’t turn down the raw carrots on the crudité platter just because you would get more nutrition from cooked carrots. For best nutrition results, partake of a variety of vegetables (eat the rainbow) and don’t fuss too much about how they’re prepared, because many variables affect the precise dose of nutrients you’re receiving. Here are some points to consider:

Volume. One advantage of eating vegetables raw is that they are still full of water, which means that you get more volume for fewer calories, which is great for providing balance to the higher-calorie foods in a meal. On the other hand, because some of vegetables’ water content is lost in cooking, you can eat more cooked veggies before feeling full, upping your nutrient intake. Dark leafy greens are a stellar example of this — think of how much kale you could eat in a raw salad versus when it’s sautéed (see recipe below).

Digestion. Some people find that they digest cooked vegetables better, because the heat softens some of the tougher fiber (making the roughage less rough). It’s a myth, by the way, that the “live enzymes” in raw vegetables enhance your own digestion. Humans have their own digestive enzymes, which do the job nicely.

Genetics. Trying to compare the nutritional quality and healthfulness of raw and cooked vegetables is complex, and not just because of the cooking, or lack thereof. Research suggests that some people make “better use” of health-promoting compounds in certain vegetables based on their genes. So for some people, broccoli might help prevent cancer, while for others it’s merely a good source of fiber, vitamins and minerals.

Storage wars. When fresh produce is shipped long distances and kept in storage before being sold, it loses some nutrients from exposure to light, air and temperature fluctuations. For top nutrition and flavor, seasonal fresh produce grown locally, or at least regionally, is your best bet. When local isn’t an option, frozen produce may give you more nutrient bang for your buck. The freezing process slightly lowers levels of some of the water-soluble vitamins, such as vitamin C and the Bs, but we also get those from other foods.

Taste and texture. The flavor and mouthfeel of vegetables varies based on whether — or how — you cook them. Do you have a strong preference for the juicy snap of raw vegetables, the crisp-tenderness of lightly blanched or steamed vegetables, or the sweet caramelization that comes from roasting? There’s nothing wrong with honoring this. If you are “picky” about how your vegetables are prepared, you can branch out by eating different vegetables, prepared similarly.

Water and heat. Cooking vegetables can reduce or enhance levels of different nutrients — but different cooking methods have different effects on different vegetables. Nutrients most likely to be destroyed by cooking are those that are both soluble in water and sensitive to heat, such as certain antioxidants. Vitamin C is one, but you can also get that from fruit. Glucosinolate, a phytonutrient found in broccoli and other cruciferous veggies, is another. When you boil cauliflower and broccoli, water-soluble glucosinolates are lost in the cooking water. Light steaming, on the other hand, preserves them, because the vegetables aren’t in direct contact with the water and the cooking time is short.

The pleasure factor. Some studies also show that levels of other antioxidant phytonutrients, carotenoids and lycopene in particular, are enhanced when vegetables are cooked. This means that you’ll get more beta-carotene out of cooked carrots than raw — but if you love raw carrots don’t let that stop you from eating them! The same is true with the lycopene in tomatoes. Just because you get more lycopene from stewed tomatoes or tomato paste than from raw tomatoes doesn’t mean you shouldn’t enjoy the summer pleasure of snacking on fresh cherry tomatoes.

The bottom line. Eating lots of both raw and cooked vegetables is a key component of a nutritious and health-promoting diet. That’s one reason why the DASH (Dietary Approaches to Stop Hypertension) eating plan, recommends 4 to 6 servings of vegetables per day and Mediterranean-style diets make abundant use of fresh vegetables, both raw and cooked.

Pancooked Kale with Garlic and Lemon

Serves 2-4

1 large bunch (or two regular bunches) of kale

2 tablespoons olive oil

5 cloves garlic, finely minced

Sea salt and freshly ground pepper, to taste

½ lemon

1. Rinse the kale then soak it in cold water for a few minutes to remove any grit. Drain and dry in a salad spinner. Tear the kale into chunks.

2. In a large skillet, heat the olive oil over medium-high heat. Add the garlic and cook it for one minute, stirring it to avoid burning.

3. Dump in the kale and use tongs to toss it and move it around the skillet. Sprinkle on the salt and pepper and continue cooking until the kale slightly wilted but still crisp, about 1 to 2 minutes.

4. Squeeze the juice of half a lemon over the top of the kale and toss again.

5. Remove the kale to a plate and serve.