Lesson 8: How Different Cooking Methods Affect Nutrient Levels In Your Food

Yes, I want my food to taste incredible, but I also want it to be super nutritious and good for me. My health, my energy level and mood, even my happiness - these all vary directly with the foods I eat and how good they are for me.

A common topic of debate on nutrition is the effect of different cooking methods on vegetables, and which one is the best.

This is important information to know, and I'll tell you exactly the pros and cons are of each cooking method. But it's equally important to get a variety of types of vegetables in your diet.

Actually, variety is probably even more important than the cooking method. Sure, you lose vitamins when you boil carrots, but if you're boiling those carrots with a bunch of different vegetables into a delicious soup, look at the upside. Making this delicious soup is probably going to get you to eat a lot more vegetables than you would if they were just chopped up raw.

And looking at the numbers, the Vitamin C lost in boiling carrots is 40%, which for 100g worth of carrots is 2.3mg. If you add 100g of baked sweet potato to your soup, you get 19.6mg of Vitamin C. This is much more effective than just opting for raw carrots, especially when the daily recommended intake of Vitamin C is 75-90mg for adults. Carrots aren't going to get you there anyway.

One factor that does really affect the nutritional value of foods is when oil is used in cooking, since it's prone to breaking down into toxic by-products. You'll see that the cooking methods relying on oil are at the bad end of my list. That doesn't mean that you should never use oil. It just means that if you are aware of the fact that oil creates some toxins, you shouldn't use it all the time in cooking and you should make sure the negative impact is minimized by using oil properly.

Above all else, make sure that you have an overall healthy diet and lifestyle so that your body can handle toxins. The truth is that there are toxins in everything we eat, they are in the air and in the water, and are very much unavoidable. Your body does have the ability to neutralize toxins if you're healthy and if you don't overload your systems.

Let's look at cooking methods.

1. Raw

I spent some time experimenting with a 100% raw diet. I lost a bit of weight and felt great. During the winter, I also felt cold and a bit weak. I think there are times when a 100% raw diet is a great idea, and I think we should always try to get a lot of raw foods in our diet.

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The main benefit of eating raw vegetables is the full vitamin and mineral content is kept intact. They also retain more fiber and water than cooked foods, things that are very valuable to many people who aren't getting enough.

However, the cell wall of the vegetables (cellulose) stays intact so certain nutrients aren't as available for absorption than in cooked vegetables. Our digestive system isn't able to break down cellulose, so cooking can release nutrients that would otherwise pass right though our digestive tract.

Raw vegetables also have the potential for toxins that inhibit our bodies' ability to digest and absorb the foods we eat, and can be more harmful if they are eaten in huge quantities. It's difficult to eat enough toxins to make yourself sick with common foods, but white mushrooms, for example, have mild toxins (hydrazines) in them that are neutralized by cooking.

Raw fruits and vegetables will start to oxidize and lose nutrients due to air contact once they are peeled or cut. Preparing your vegetables immediately before eating them and avoiding storing cut vegetables in the fridge will minimize that effect.

2. Marinate/Massage

Marinating and massaging foods with salt, herbs, spices and other dressings uses no heat, so most vitamins and minerals are retained, aside from the ones lost through air exposure.

Using salt to marinate or massage vegetables draws moisture out of the plant cells and starts to break down the cellulose. It's not broken down to the same level as cooking, but it softens the fiber making digestion a bit easier, and makes certain nutrients more available for absorption.

Marinating with certain acids can neutralize the toxins in raw vegetables, and make proteins more digestible. Some of the toxins found in certain mushrooms can be neutralized by marinating them with citric acid, from lemons or oranges, for a few hours.

Plus, both of these techniques help bring out the flavors of vegetables and make for a tastier meal.

3. Steam

Steaming is a great option for cooking vegetables since it avoids a lot of the ways in which nutrients are lost, but also breaks down fiber and toxins to optimize absorption. Water doesn't contact the vegetable, so vitamin and mineral leaching is minimal.

There is some vitamin loss through heat, and some of the water in the vegetable evaporates. If the vegetable is peeled and/or cut before cooking, some vitamins and minerals will also be lost due to air contact during the time it cooks and before serving. Steaming vegetables when they're whole, and peeling and cutting them after they're cooked, will avoid that issue.

4. Boil

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Vitamins and minerals leach into water, and you can still get those that aren't destroyed by heat if you use the broth. If the cooking water is thrown away, boiling would slip below baking on the healthy cooking method ladder since it has the most nutrient loss.

Boiling usually brings the temperature of the vegetable higher than steaming, causing more vitamin loss through heat.

As with all cooking methods, boiling softens fiber, breaks down cellulose, and allows for more absorption of the energy and nutrients in the vegetables.

5. Bake (No Oil)

Temperatures for baking are usually higher than steaming or boiling, but can be any temperature. To bake with no oil, the foods need to be kept whole with skin intact, otherwise they'll dry out with the heat.

Baking doesn't use any water so minerals are retained and vitamin loss is only due to heat. When baking is defined as being done with the vegetable and skin intact, this minimizes contact with the air and also reduces nutrient loss when compared with boiling.

If foods are baked with some water in the dish, they're going to be cooked by a combination of steaming and baking.

6. Roast (With Oil)

Temperatures for roasting are usually at the high end of baking range. Foods are peeled or cut, and need some oil to protect them from drying out in the heat. Heating oil creates some free radicals, particularly at temperatures above 300 degrees F.

Roasting and frying are a bit of a toss up as to which one is better, and it depends on the time and temperature factors. Roasting takes a longer time, but it's usually done at a lower temperature than frying. Both factors create increased potential for free radicals forming in the oil, so the exact numbers could make one better than the other. Roasting doesn't use any water so minerals are retained and vitamin loss is only due to heat and air contact.

7. Fry

Temperatures used for frying are generally higher than for other cooking methods. Foods are usually peeled or cut, exposing them to oxidation and nutrient loss, and need some oil to protect them from drying out on the heat. Heating oil creates some free radicals, particularly at temperatures above 300 degrees F.

The upside of frying is that it takes very little time, so the foods are exposed to heat for a shorter period than baking or roasting. It also doesn't use any water so minerals are retained and vitamin loss is only due to heat and air contact.

Frying with water, sometimes called water sauteeing, is technically cooking by steaming so the pros and cons are covered above.

Serving – Method and Time

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Foods continue to cook and lose nutrients when left to sit, and exposure to air speeds the loss. A study looked at baked potatoes, and found that they lost 20% of ascorbic acid during cooking, and a further 39% after 43 minutes on a hot plate. Another study looked at steamed potatoes that had lost 39% of their ascorbic acid during cooking, and found that they lost almost all of the remainder when mashed and allowed to stand.

That looks at just one nutrient, and many other nutrients in vegetables are more stable than ascorbic acid, but in general keeping foods as whole as possible for as long as possible when storing, cooking and serving will help preserve their nutrients.

Again, it's not about avoiding every possible thing that will reduce nutrient levels, it's about being aware of how the loss happens so that you can make good choices overall for your diet. Remember too that variety plays a huge role in making sure you get enough of all the nutrients you need, and can often offset the effects of different cooking methods.

Being optimally healthy is about finding those methods and foods that work best for you. Once you find and maintain that balance of health, you'll be able to handle most things thrown at you without worrying so much.

Cheat Sheet: Cooking Methods & Nutrient Levels

Your Turn!

Which cooking methods are your favorites, that you use most often? Let me know by leaving a comment below! And let me know if you have questions, or if I missed something you were wondering about!

Download the cheat sheet for today's lesson: Cheat Sheet: Cooking Methods & Nutrient Levels

And check out the other posts I've linked from the photos down the right side of the page - they have lots more info and videos that I think you'll really enjoy.

*If you stumbled across this lesson and haven't signed up for the rest of the course, you can do that here: Free meal plan + mini-course

Recipe: Jicama Salad with Basil Mango Recipe

Jicama Salad with Basil Mango Recipe

Mango again! I told you, I'm addicted! But this is also fantastic with avocado in place of the mango if you prefer.

I have tons of recipes on my site using all these different cooking methods, but I wanted to highlight a technique for making a raw starchy vegetable more delicious.

I show you how to marinate raw jicama, for a fresh and tasty summer salad that's filling enough to serve as a meal.

Watch me make the salad and dressing!