Raw vs. Cooked: Do You Believe Dr. Fuhrman's Take? What's Your Stance?
This is from Joel Fuhrman M.D., a board–certified family physician who specializes in preventing and reversing disease through nutritional and natural methods:
Raw vs. Cooked?
Certainly, there are benefits to consuming plenty of raw fruits and vegetables. These foods supply us with high nutrient levels and are generally low in calories too. Eating lots of raw foods is a key feature of an anti-cancer diet style and a long life. But are there advantages to eating a diet of all raw foods and excluding all cooked foods? The answer is a resounding “No”. In fact, eating an exclusively raw-food diet is a disadvantage. Excluding all steamed vegetables and vegetable soups from your diet narrows your nutrient diversity and has a tendency to reduce the percentage of calories from vegetables in favor of nuts and fruits which are lower in nutrients per calorie.
Raw vegetables are dramatically low in calories and we probably only absorb about 50 calories a pound from raw vegetables. Our caloric needs cannot be met on a raw food diet without consuming large amounts of fruits, avocado, nuts and seeds. This may be an adequate diet for some people, but in my 15 years of medical practice catering to the community of natural food enthusiasts, raw foodists and natural hygienists, I have seen many people who weakened their health on such raw food, vegan diets. Frequent fungal skin and nail infections, poor dentition, hair loss and muscular wasting are common on such fruit-based diets.
Unfortunately, sloppy science prevails in the raw-food movement. Raw food advocates mistakenly conclude that since many cooked foods are not healthy for us, then all cooked foods are bad. This is not true.
The idea that stirs the most enthusiasm for this diet is the contention that cooking both destroys about fifty percent of the nutrients in food, and destroys all or most of the life promoting enzymes. It is true that when food is baked at high temperatures—and especially when it is fried or barbecued—toxic compounds are formed and most important nutrients are lost. Many vitamins are water-soluble, and a significant percent can be lost with cooking, especially overcooking. Similarly, many plant enzymes function as phytochemical nutrients in our body and are useful to maximize health. They, too, can be destroyed by overcooking. However, we cannot paint with this brush of negativity over every form of cooking.
Only small amounts of nutrients are lost with conservative cooking like making a soup, but many more nutrients are made more absorbable. These nutrients would have been lost if those vegetables had been consumed raw. When we heat, soften and moisturize the vegetables and beans we dramatically increase the potential digestibility and absorption of many beneficial and nutritious compounds. We also increase the plant proteins in the diet, especially important for those eating a plant-based diet with limited or no animal products.
In many cases, cooking actually destroys some of the harmful anti-nutrients that bind minerals in the gut and interfere with the utilization of nutrients. Destruction of these anti-nutrients increases absorption. Steaming vegetables and making vegetable soups breaks down cellulose and alters the plants’ cell structures so that fewer of your own enzymes are needed to digest the food, not more. On the other hand, the roasting of nuts and the baking of cereals does reduce availability and absorbability of protein.
When food is steamed or made into a soup, the temperature is fixed at 100 degrees Celsius or 212 Fahrenheit—the temperature of boiling water. This moisture-based cooking prevents food from browning and forming toxic compounds. Acrylamides, the most generally recognized of the heat-created toxins, are not formed with boiling or steaming. They are formed only with dry cooking. Most essential nutrients in vegetables are made more absorbable after being cooked in a soup and water-soluble nutrients are not lost because we eat the liquid portion of the soup too.
Recent studies confirm that the body absorbs much more of the beneficial anti-cancer compounds (carotenoids and phytochemicals—especially lutein and lycopene) from cooked vegetables compared with raw. Scientists speculate that the increase in absorption of antioxidants after cooking may be attributed to the destruction of the cell matrix (connective bands) to which the valuable compounds are bound.
Another fallacy promoted in the raw food movement and on the web is that the fragile heat-sensitive enzymes contained in the plants we eat catalyze chemical reactions that occur in humans and aid in digestion of the food. This is not true. Plant foods do not supply enzymes that aid in their digestion when consumed by animals. Our body supplies exactly the precise amount of enzymes needed for digestion; we are not ill equipped to digest normal food. The plant enzymes are broken down into simpler molecules by our own powerful digestive juices and even those that are absorbed as peptide size pieces (or with some biologic function) do not function to catalyze human functions. So it is not true that eating raw food demands less enzyme production by your body. A healthy body produces the precise amount of enzymes needed to digest the ingested food appropriately and the enzymes our body uses for other processes are unique to our human needs and are not present in plants. We make what we need from the proper materials.
In conclusion, eating lots of raw foods is a feature of a healthy diet. I always encourage people to eat more raw food. One of my common statements is—the salad is the main dish. Raw food is necessary for digestive efficiency, proper peristalsis and normal bowel function. Certain foods, especially fruit, avocado and nuts undergo significant change with cooking and are best eaten raw. Baking, frying, barbecuing and other high heat cooking methods that brown and damage food form acrylamides, which are carcinogenic. Browning and other high heat cooking methods should be avoided. Cooking techniques like steaming vegetables, stewing foods in a pressure cooker and soup making, do not have these drawbacks. They do not brown foods or form acrylamides.
Eating raw food is necessary for good health and is an important feature of a healthy diet. But that does not mean that one’s entire diet has to be raw to be in excellent health. It also does not mean eating an all raw diet is the healthiest way to eat. It is healthier to expand your nutrient density, your absorption of plant protein and your nutrient diversity with the inclusion of some conservatively cooked food in your diet.
Link LB ; Potter JD. Raw versus cooked vegetables and cancer risk.
Cancer Epidemiol Biomarkers Prev. 2004; 13(9):1422-35.
Ismail A ; Lee WY. Influence of cooking practice on antioxidant properties and phenolic content of selected vegetables. Asia Pac J Clin Nutr. 2004; 13(Suppl):S162.
Tags: cooked, eating, health, high, percentage, raw, soups, steamed, wellness
Replies to This Discussion
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Permalink Reply by John on -
Maybe I unsubscribed from Fuhrman's newsletter too soon?...
Overall he says a lot of good things and let's not throw the baby out with the bathwater - it is fantastic to have M.D.s educate people that "Eating raw food is necessary for good health and is an important feature of a healthy diet.", after all that is what's important. If we, as a population, only included steaming and boiling vegetables and legumes as the extent of cooking then there likely would never be a debate about the harm of cooked foods.
While I cheer for Fuhrman's efforts to educate, here are a few questions and issues I see with what is presented above that I don't think have been addressed yet:
- how does "excluding all steamed vegetables and vegetable soups from your diet narrow your nutrient diversity?
- "we probably only absorb about 50 calories a pound from raw vegetables"? probably? now that's sloppy science - How does cooking a vegetable make the "calories more absorbable"? (and I won't get started on why the entire Calorie model is almost useless)
- how is it that we "increase the plant proteins in the diet [by cooking them]"? are proteins created in the cooking process?
- "When food is steamed or made into a soup, the temperature is fixed at 100 degrees Celsius or 212 Fahrenheit—the temperature of boiling water." Let's talk sloppy science again. While the temperature of pure water is 100/212 the temperature of soup is quite different, the more "stuff" in it the higher the temperature needed to boil (for those who boil soup, put a thermometer in it next time and report back). And as far as steam goes... how does the additional 540 calories/gram of energy effect the nutrients? He also advocates "stewing foods in a pressure cooker" anyone care to guess the temperature and energy created in a pressure cooker?
- "Another fallacy promoted in the raw food movement and on the web is that the fragile heat-sensitive enzymes contained in the plants we eat catalyze chemical reactions that occur in humans and aid in digestion of the food. This is not true. Plant foods do not supply enzymes that aid in their digestion when consumed by animals. Our body supplies exactly the precise amount of enzymes needed for digestion; ... The plant enzymes are broken down into simpler molecules by our own powerful digestive juices" I'd like to know more about how that relates to what he said earlier - "many plant enzymes function as phytochemical nutrients in our body and are useful to maximize health. They, too, can be destroyed by overcooking."
Ultimately, I believe the more raw food the better but I am not so against the idea that some cooked vegan foods can be good for you too.
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Permalink Reply by Debbie Took on
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Good points, John! :-)
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Permalink Reply by John Coleman on -
So what's wrong with juicing? Why doesn't that figure in his program? You can easily eat pounds of veggies using a juicer. It uses far less energy than a cooker and does not destroy or nutrients.
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Good point.
Juicing copes with all those 'cooked food arguments' revolving around cases where people have impaired digestive capabilities.
And at least some of the fibre (pulp) can be stirred back in, if desired.
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Permalink Reply by Rawgreengoddess on -
i believe juicing can and would benefit anyone....its loads of awesome minerals absorbed easily!
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Asafoetida: It depends on the exact food--he's being approximate. And cooking opens the plant cell walls that are indigestible, so we can digest what's inside.
Blending is a better way of doing this.
See my discussion of tomatoes and lycopene here:
http://debbietookrawforlife.blogspot.com/2008/03/are-some-foods-bet...
BTW, re the enzymes argument, actually, most raw foodists don't use that any more. That's not to say that it doesn't have merit - it's simply that it has been an area of such huge debate that raw foodists nowadays tend to focus on loss of vitamins, denaturing of protein, toxins created etc. The problem of course is that those advocating cooking of food find those arguments hard to disagree with, so they hark back to what raw foodists were saying a few years ago instead.
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Permalink Reply by John on
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Asafoetida: "It depends on the exact food--he's being approximate. And cooking opens the plant cell walls that are indigestible, so we can digest what's inside."
Debbie Took: "Blending is a better way of doing this."
Blending is suppose to rupture the cell wall and cooking is suppose to rupture the cell wall so lets assume that both processes results in access to the nutrients contained within.
Let's look at some data from the USDA National Nutrient Database for Standard Reference with regard to some of the nutrition of Raw Kale and Cooked Kale (boiled and drained - unfortunately there is no data on Kale soup to include possible nutrients in the water)
100 grams - Raw -vs- Cooked
Energy: 50 kcal - 28 kcal
Protein: 3.3g - 1.9g
Lipids: 0.7g - 0.4g
Fiber: 2.0g - 2.0g
Ca: 135mg - 72mg
Fe: 1.7mg - 0.9mg
Mg: 34mg - 18mg
Vit C: 120mg - 41mg
Folate: 29mcg - 13mcg
Beta Carotene: 9226 mcg - 8173 mcg
Lutein/Zeaxanthin: 39550 mcg - 18246 mcg
I think I'll go make a green smoothie with kale right now!
... and the "Enzyme Therapists" long ago talked about the benefits of Plant Enzymes in digestion starting with Dr. Howell in the 1920's before raw foodists evolved =)
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Permalink Reply by John on
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Asafoetida - I'd love to read more about studies of calories that lock people in a room. I'm not aware of any such studies specific to calories and people - please post links or resources. Thanks!
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Permalink Reply by ben "the beekeeper" stiller on -
Connie,
Google search... I found http://www.diseaseproof.com/archives/debunking-diet-myths-grapefrui...
UPDATE: Here's what Dr. Fuhrman had to say: This is not new. I have been advising women on DrFuhrman.com not to consume too many grapefruits, not more than 2 weekly for the last year or so just to play it safe. The issue is a compound in grapefruit that interferes with the breakdown of estrogen. Whereas green vegetables aid in the breakdown of estrogen for easy excretion of excess by the body.
So there's your answer. Like any doctor worth their salt would say to lay off something if it looks like it may cause issues in the body.
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Permalink Reply by John Coleman on
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Put the steamer away and juice the veggies instead - less energy used more nutrients retained.
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Permalink Reply by sabrina on -
Yes! Many of us are trying to heal illness! I wish I heard more about what's working for people with various ailments, etc.
What would be best for steaming? I have a plastic based rice/veggies steamer I used to use but eweee, plastic! What about crock pots? Would those be an ideal way if you're making a cooked soup?
Also, I appreciate this conversation because I think it's important to keep our minds open. How many times have we come across a belief, latched onto it and then later changed our minds? I love how I feel when I drink lots of green smoothies and I'm trying to keep my diet to: 2 green smoothies, 1-2 green juices, 1 salad with sprouts, fish or seeds (rotation) and steamed veggies or soups. I'm trying to heal chronic fatigue, candida, depression, hormonal imbalances, etc. Each day I'm learning about diet and health. I think the most important realization I've come to is that #1 for my healing is relaxing. I'm just rolling with whatever happens and avoiding getting stressed or having emotional breakdowns. I try to eat well, but everytime my ego wants to create fear about not healing, I just remember that the best thing I can do is think well. Eating well is important, but so is thinking well :) Thats my little story :p
<3
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