Health & Body-Boosting

Kitchen Talk: How Cooking Affects Vegetables

Mon Jul 5

The thing that we really love about veggies (besides their nutritional value, of course) is that there is a seemingly endless list of ways to prepare them. Veggies can be enjoyed roasted, steamed, sauteed, and even raw. If you can think of a cooking method, chances are it can be applied to a vegetable.

But does cooking make your vegetables less healthy?

You may have heard from the proverbial grapevine that cooking veggies can affect their nutritional content. This is true, but it’s not necessarily a bad thing. 

Certain nutrients are indeed heat-sensitive so a turn in the oven or grill really will lessen a veggie’s nutritional value in that sense. That said, other nutrients aren’t really affected. Some can even be increased or made easier to absorb from the cooking process.

Let’s take a closer look.

According to a 2009 article by Scientific American, cooking veggies softens them, making the food easier to both chew and digest (handy if you have issues with either). Cooking some veggies breaks down the cell walls, making it easier for us to absorb certain nutrients.

The aforementioned article cited studies indicating that some cooking methods can actually increase the antioxidants that our bodies get from vegetables. For example, one study showed an increase of lycopene in tomatoes.

On the flip side, other nutrients like water-soluble vitamins (vitamin C and B vitamins for example) and fat-soluble vitamins (like vitamins A and K ) can be reduced by cooking.

It seems that, as with many things, balance is a good idea.

Comparing Cooking methods

Once you’ve decided to cook a vegetable, cooking it in certain ways can help keep the nutritional content up. There’s no perfect cooking method that will guarantee you don’t lose any vitamins, but there are a few tricks to keep that loss relatively low.


frying vegetables

As much as we would like it to be otherwise, frying is not really a good way to preserve the nutrients in your vegetables (was there ever any chance?).

To this method’s credit, frying cooks vegetables rather quickly which cuts down on the time available for nutrients to be lost. Generally, B vitamins and vitamin C might not fare too badly. However, deep-frying will cause beta-carotene and vitamin A to take a hit while upping the caloric and fat content of your veggies.

Additionally, frying at high temperatures can even cause toxins called aldehydes to form. As can probably be gleaned from the word “toxins’, these are not something you want to be consuming too often. They’ve been linked to an increased risk of cancer.

While it’s best to avoid frying foods too often, alas our taste buds are traitorous fiends. If you do want to occasionally go this route, try to keep your cooking time to a minimum and use a healthier oil. 



Alternatively, you can also try stir-frying. This method cooks food for a shorter period of time without water which can help preserve B vitamins. Vitamin C might take a hit, but lycopene in tomatoes and beta-carotene in carrots can increase. And if you stir-fry with olive oil, that can help increase your absorption of phytonutrients.



When cooking vegetables, it’s usually better to use as little water as possible so that important nutrients don’t leach out, particularly the water-soluble ones like vitamin C and folate. 

These nutrients will go into the water you’re cooking in so if you’re making a soup or stew (or for some reason planning to drink the water) it’s not so much of a concern. If your plan was to dump your cooking water down the drain, though, that’s another story.

Of course, that’s not to say that boiling is bad, but if you do want to boil your food, try to keep the cooking time down. Also, maybe consider steaming. This method is widely considered to be one of the healthiest.  And if you can steam veggies whole, so much the better.


roasted vegetables

Roasting vegetables can be a good way to get vegetables into the mouths of some picky eaters. Even better, it’s healthy.

Roasting veggies doesn’t require water that will cause nutrients to seep out nor do you need an excessive amount of oil  that will add unwanted fats and calories (although a little bit of olive oil can certainly be a good addition).

That said, as with any cooking method, the nutrient content will be affected. Exactly how depends on the vegetable. For some veggies, the number of nutrients will, unfortunately, go down a bit. On the other hand, though, there are also some veggies that will become more nutritious, or at least certain nutrients will be more accessible after cooking

In general, some good ways to keep lost nutrients at a low is to use veggies that aren’t too ripe, roast them with their peels, and try not to cut them into too small of pieces (yep, that also plays a part).

The takeaway

No cooking method is absolutely perfect and they all have their pros and cons. As such, the best way to go is to eat your veggies cooked in a variety of ways. Go with soup on some days, a salad on others, and roasted on others. This way, you’ll have a lot of options for enjoying your vegetables. Plus, it’ll keep life interesting.