There is some misinformation out there about the benefits of eating everything raw. Specifically, raw vegetables are often credited for providing the most nutritional bang for your buck. This is only partially true. While some nutrients get lost in cooking, others rely on cooking to perform their best. Not only are certain nutrients released in higher temperatures, but cooking can also make certain nutrients more digestible. Better digestion yields better absorption.
Research on carotenoids, a group of pigments found in many orange-yellow-red foods helps make the case for cooking veggies. Lycopene, a member of the carotenoid family, gets released during cooking; meaning a tomato eaten raw out of your garden will have less lycopene than if you'd given it some heat.
Cooking is also responsible for helping make proteins in vegetables easier to digest. Evidence also shows most minerals (zinc, calcium, iron, etc.), phytochemicals, and fat-soluble vitamins (A, D, E, and K) are largely unaffected by cooking. Though fiber's integrity is often questioned after cooking, there isn't adequate research to support eating raw veggies only.
Where the raw foods argument wins is with water-soluble vitamins (includes the B vitamins, thiamin, niacin, riboflavin, folic acid, etc. and vitamin C), which tend to be lost with heat. The good news is that much of the majority of these nutrients are highly available in other foods. For example, breakfast cereals cover us on many B vitamins and eating a piece of citrus fruit covers the bases for vitamin C. In other words, variety trumps preparation.
Cooking time, temperature, and added liquid are commonly listed as key components to causing greater damage to heat-sensitive nutrients. Hence stir frying or microwaving are often cited as safer bets than boiling or even steaming. And to add to the argument against adhering only to a raw foods diet- chopping and peeling can affect nutrient content too.
As with most nutrition-related topics, variety is key. Choose the colors of the rainbow and prepare them in various ways. Eat them raw, steamed, grilled or stir fried and you won't have to worry about extracting every last milligram of possible vitamin C out of a bell pepper.
Also, keep personal preference in mind. People are more likely to eat more of something they enjoy, right? So don't force raw asparagus, for example, when your mouth waters for grilled. When it comes to veggies, more in any form is always better than less of the "the right" form. You'll get more enjoyment- and likely more nutrients overall simply because you savor the flavor!
Tanya Zuckerbrot, MS, RD is a nutritionist and founder of www.Skinnyandthecity.com. She is also the creator of The F-Factor DietaC/, an innovative nutritional program she has used for more than ten years to provide hundreds of her clients with all the tools they need to achieve easy weight loss and maintenance, improved health and well-being. For more information log onto www.FFactorDiet.com.