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Eating Well – Is Fresh Food Always Your Best Option?

By Sara Lee Thomas, Registered Dietitian, Good Samaritan Regional Medical Center

Eating fresh, in-season fruits and vegetables is a great way to maximize taste and nutrition while minimizing cost. However, we often get the idea that “fresh” or “raw” is always better than “processed” and “cooked”. This is true sometimes, but not always. Fresh, frozen, canned and cooked can all be healthy and convenient choices year around.

Vitamin C is the most vulnerable nutrient to being lost at all steps of food handling, storage and cooking. For this reason, fresh-frozen can actually have more vitamin C than fresh produce that has been sitting around for a few days. However, for some other nutrients there can be benefits to cooking as long as we avoid overcooking. 

Cooked Vs. Raw Food Considerations

Cooking can prevent illness, make food more digestible and make some nutrients more available to your body.  Examples: While fresh tomatoes have more vitamin C, canned tomatoes give you several times more cancer fighting lycopene. You also get more minerals out of roasted nuts than raw and cooking increases the availability of certain antioxidants in corn.

Cooking food also lets us get more energy out of less food, especially starchy plant foods where cooking increases availability of calories by 12 to 35 percent. Historically, this has been a great advantage since the human brain needs 400 to 500 calories a day from carbohydrates. 

But wait, wouldn’t fewer calories be better in present times? Maybe, but only if it is not taken to extremes. Diets that were “100 percent raw” with all raw plant food have resulted in malnutrition and infertility. On the other hand, one small study found that a partial raw plant foods diet (60 percent raw) helped adults gradually lose 15 pounds on average.

For high-protein foods, however, cooking can save your life. According to the FDA, food borne illness affects 1 in 6 Americans each year and results in about 128,000 hospitalizations and 3,000 deaths. People at highest risk are pregnant women, babies, young children, older adults and those with a chronic disease. Foods with higher risk are high-protein, high-moisture foods (beef, pork, chicken, turkey, fish, eggs, etc.). Proper cooking and handling can prevent most food borne illnesses. Refer to for more information.

On the other hand, overcooking is obviously bad because it destroys many nutrients and makes vegetables taste bad, especially for kids. Raw, steamed, microwaved or stir fried vegetables generally taste better and keep more nutrients than boiling. Boiled vegetables can lose up to half their potassium, steamed vegetables only lose 6 percent.  Aim for less water and shorter cooking times. 

Variety in Your Diet Is a Good Thing

So what’s the bottom line? Variety is still great nutrition advice, so mix it up. Try out and enjoy the taste and nutrition from the full rainbow of fresh, frozen, canned and cooked fruits and vegetables. Limit added fat and sugar. Steam, microwave or stir fry to reduce nutrient loss. Don’t overcook vegetables. Limit or avoid grilling and high heat cooking/frying. And always follow food safety guidelines.

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Article adapted from author’s article in Oregon State University’s Linus Pauling Institute Healthy Youth ProgramSpring 2015 Newsletter.