These days, most of us know that what we eat (including what your food has eaten!) has a profound impact on our health. The old saying "You Are What You Eat" has never before carried such weight.
Over the last 30 years, obesity, diabetes, and heart disease rates have all skyrocketed in direct correlation with the quantity of refined sugar, high fructose corn syrup, and hydrogenated oils that have been used by the packaged and fast food industires1. For those of us looking to avoid these chronic conditions through a diet of unrefined and unprocessed whole foods and a healthy lifestyle, we need to consider not just the quality of food that we buy, but what cooking methods will best preserve the nutrients in the food.
While raw foods like salads have many benefits, such as maintaining the natural enzymes, vitamins, antioxidants, phytonutrients, and natural fibers in the foods. Although raw foods also alkalinize and detoxify the body, which is so important in our modern world filled with a plethora of chemical toxins, most people do not find that eating a completely raw diet is a good choice for them. Although many enzymes and phytonutrients are lost at temperatures over 118 degrees, cooking can actually improve the digestibility and absorption of nutrients in many foods. For most of us, we can enjoy fruits and raw vegetables and salads as an important part of a healthy diet throughout the summer, but find that as the weather turns colder we crave heavier cooked meals that contain more good fats and protein. The vegetables of fall and winter are the hard squashes and root vegetables, which with a little know-how can be cooked in ways that maximize both their nutritional content and digestibility.
What’s Wrong With Boiling?
If you have already made a point of cleaning up your diet and have made the switch from processed foods and frozen dinners to organic vegetables and hormone-free meats, then it is REALLY worth your while to make sure that you preserve as much nutrition as possible during the cooking process. Unfortunately, many people are still using cooking methods that completely destroy the nutrients found in unprocessed whole foods. Not only is it a waste of money, but with improper cooking methods, the intended health benefits of a healthier diet are completely lost!
Traditional methods of cooking here in the South, such as boiling vegetables and deep frying fish and chicken, have their origins in England, but that doesn’t mean that nutrient preservation was the objective. Boiling vegetables was just the way vegetables had been cooked for centuries, but that didn’t mean that all the other methods of how to best retain the color, flavor, texture and nutrient content had been tried or explored. Boiling was just the way you cooked your vegetables, and was handed down from generation to generation. But now studies have shown us that the valuable vitamins, antioxidants and phytonutrients recently discovered in all types of vegetable are actually destroyed through boiling.
A recent study conducted in the U.K. showed boiling vegetables that are members of the cruciferous family, including cabbage, broccoli, and brussels sprouts, significantly reduces their anticancer properties. The active anticancer ingredient which is destroyed by the boiling process is called gucosinolate. Glucosinolate is an important compound that converts inside the body to a cancer fighting chemical called isothiocynate which helps to remove cancer causing components from our system. When cruciferous vegetables are boiled, most of this important compound is destroyed along with the cancer protective properties.2
But do you lose ALL the important vitamins and nutrients from your vegetables when you boil them? The preponderance of evidence suggests there is some truth to this. It's been shown when we boil vegetables, a considerable amount of the vitamins leech out into the cooking water are poured down the drain. This will vary depending on how much water is used in the cooking process as well as how long the vegetables are exposed to hot water- regardless of the specifics, it certainly seems disheartening to eat your vegetables as recommended and not get the full anticancer and vitamin protection!
What About Microwaving?
Since the traditional method of boiling has failed us, perhaps the modern technology of microwaving has provided the answer! It would be wonderful if that was the case, but unfortunately more and more studies since the invention of microwave ovens over 40 years ago have shown otherwise. Microwaves heat food by causing water molecules in it to resonate at very high frequencies and eventually turn to steam which heats your food. While this can rapidly heat your food, what most people fail to realize is that it also causes a change in your food's chemical structure.
The first thing you probably noticed when you began microwaving food was how uneven the heating is. "Hot spots" in microwaved food can be hot enough to cause burns—or build up to a "steam explosion." This has resulted in admonitions to new mothers about NOT using the microwave to heat up baby bottles, since babies have been burned by super-heated formula that went undetected.
Another problem with microwave ovens is that carcinogenic toxins can leach out of your plastic or paper containers and covers, ending up in your food. The January/February 1990 issue of Nutrition Action Newsletter reported the leakage of numerous toxic chemicals from the packaging of common microwavable foods, including pizzas, chips and popcorn. Chemicals included polyethylene terpthalate (PET), benzene, toluene, and xylene. Microwaving fatty foods in plastic containers leads to the release of dioxins (known carcinogens) and other toxins into your food.3 One of the worst contaminants is BPA, or bisphenol A, an estrogen-like compound used widely in plastic products. In fact, dishes made specifically for the microwave often contain BPA, but many other plastic products contain it as well.
But THE most important reason not to cook your whole foods, or your frozen organic dinner (sold in a plastic container!), in the microwave is that microwaving distorts and deforms the molecules of whatever food or other substance you subject to it. An example of this is blood products. Blood is normally warmed before being transfused into a person. Now we know that microwaving blood products damages the blood components. In fact, one woman died after receiving a transfusion of microwaved blood in 1991, which resulted in a well-publicized lawsuit.4
I know that by now you must be asking yourself the $100,000 dollar question, “How is it that a product that sits in more than 90 percent of kitchens, as well as practically every break room in the country, would be allowed to be sold if it wasn’t safe?” Good question! Because over the last 20 years numerous excellent scientific data has been gathered regarding the detrimental effects of microwaves on the nutrients in your food. A study published in the November 2003 issue of The Journal of the Science of Food and Agriculture5 found that broccoli "zapped" in the microwave with a little water lost up to 97 percent of its beneficial antioxidants. By comparison, steamed broccoli lost 11 percent or fewer of its antioxidants.
A 1999 Scandinavian study of the cooking of asparagus spears found that microwaving caused a reduction in vitamin C6. In a study of garlic, as little as 60 seconds of microwave heating was enough to inactivate its allinase, garlic's principle active ingredient against cancer7. And in a Japanese study by Watanabe showed that just 6 minutes of microwave heating turned 30-40 percent of the B12 in milk into an inert (dead) form8. It is this study has been cited by Dr. Andrew Weil as evidence supporting his concerns about the effects of microwaving. Dr. Weil wrote: "There may be dangers associated with microwaving food... there is a question as to whether microwaving alters protein chemistry in ways that might be harmful." These are just a few of the thousands of studies showing the adverse effects of cooking in a microwave, not to mention concerns about the radiation exposure (while its running it can expose you to upwards of 400 milliGauss, and a mere 4 milliGauss has been firmly linked to leukemia), and microwave ovens were actually banned in Russia in 1976 following 20 years of extensive research!
So What Are The Healthy Cooking Methods?
If boiling and microwaving your food destroys the nutrients, how are you supposed to cook it? Well, there are actually several different ways to prepare and cook delicious and satisfying meals AND benefit from the quality of the food that you’re eating! The first and perhaps easiest is cooking in our Gourmet Cooker, perfect for hardy soups and stews. While you may be using water or stock to cook your vegetable and meat in, the liquid, and all the vitamins and antioxidants, are retained in the broth. Another plus is the low temperatures that slow-cookers cook at, much like grandma’s special soup that would cook all day, except that you can turn it on, go to work, and have a delicious hot and healthy meal for the family when you get home!
Another easy way to cook vegetables, chicken, fish and beef is to bake it in the oven in your favorite sauce, what most of us would call a casserole. Baking allows the foods to cook in their own moisture and take on the flavors of the sauce and other foods; the combinations are endless, and probably every ethnic group has their own favorite baked dish. Baking meals can also free up your time while dinner is in the oven, and encourage you to make enough for lunch the next day. Sweet potatoes, squashes and parsnips are all lovely fall foods that become full of their sweet flavor through baking. And after the casserole comes out of the oven you can pop in a healthy dessert, like apples cored and filled with honey, nuts and cinnamon (baked apples!).
For stove-top cooking, using a metal or bamboo steaming basket is another way to cook vegetables without losing all the nutrients in the water. Although the temperature is higher for steaming (240 degrees) instead of boiling (212 degrees), you steam for a much shorter time, usually only 3-4 minutes max depending on the vegetable, but you do have to make sure that you don’t over-cook your vegetables.
Stir-frying is another popular way to cook both vegetables and meats. Cooking at a very high temperature for a very short time locks in the flavors and juices of the foods, preserving the texture and freshness of the food. When stir-frying, however, you must make sure you have a healthy high temperature oil like organic unrefined coconut oil and a top quality stainless steel wok like out Multi-Cooker (yes- Teflon is also very bad for you and leaches chemicals into your food!).
But for the lowest cooking temperature, and by far the healthiest and easiest cooking method available, American-made Kitchen Craft and Lustre Craft 7-clad stainless steel cookware is the answer.
Invented in 1906 in West Bend Wisconsin, waterless cookware has allowed generations of Americans to keep the nutrients, moisture and flavors in their foods and in their bodies. Kitchen Craft and Lustre Craft Waterless cookware is constructed in such a way that it’s 7 layers of metal hold the heat and cooks the food from all sides at once. Each pot is much like a Dutch oven with a specially designed cover that keeps all the moisture in. You cook at a lower temperature, always medium-low, for a shorter cooking time with little to no water! Vegetables, meat, and fish cook in their own natural moisture, not only eliminating need to boil or steam vegetables, but it also eliminates the need to fry with unhealthy oils.
For more information on how waterless cookware works, visit our page on "Benefits of Waterless Cookware.” Make sure to read the results of the study comparing different methods of cooking and watch the videos on the page while you are there. Happy Cooking!
- Jeffry Gerber M.D.
- Kristie Leong M.D.
- Watanabe F, Takenaka S, Abe K, Tamura Y, and Nakano Y. J. Agric. Food Chem. Feb 26 1998;46(4):1433-1436
- NEXUS Magazine, Volume 2, #25 (April-May '95)
- Vallejo F, Tomas-Barberan F A, and Garcia-Viguera C. "Phenolic compound contents in edible parts of broccoli inflorescences after domestic cooking"
- Kidmose U and Kaack K. Acta Agriculturae Scandinavica B 1999:49(2):110-117
- Song K and Milner J A. "The influence of heating on the anticancer properties of garlic," Journal of Nutrition 2001;131(3S):1054S-57S
- 8 Watanabe F, Takenaka S, Abe K, Tamura Y, and Nakano Y. J. Agric. Food Chem. Feb 26 1998;46(4):1433-1436