Some nutrients are destroyed by cooking but some nutrients become more absorbable.
Image thanks to Robin Zebrowski
Is it better to eat our vegetables raw or cooked? If you're thinking raw, you're right! But if you guessed cooked, you're also right! A number of nutrients like vitamin C are partially destroyed by cooking. On the other hand, some nutrients become more absorbable upon cooking. For example, we get three times more antioxidants in cooked carrots than raw. More cancer fighting indoles in cooked broccoli and more lycopene in cooked tomatoes. Leavening increases the mineral absorption in grain products and dry roasting can increase the mineral absorption from nuts. There's no good evidence that raw diets are superior to other whole foods, plant based diets. In fact, the published evidence that does exist is fairly disappointing. The only dietary survey that I'm aware of found raw food diets deficient in energy, protein, vitamins B12 and D, calcium, selenium and zinc. There are a number of seriously flawed myths that circulate within the raw foods community like the belief that we only have a limited amount of enzymes in our body that somehow get used up and so we need to consume live plant enzymes which are deactivated by cooking. Well they're deactivated by our stomach acid too, but even if they weren't specific enzymes catalyze specific reactions within our body and since we're not plants, we have no need for plant enzymes. Our body makes all the enzymes we need to function from the protein we eat and cooking actually renders proteins more digestible. So i advocate eating a combination of cooked and raw foods. Having said that, we should all be eating down huge salads everyday. We could easily polish off five cups of spinach in one sitting and that's how we have to think of greens, not as some little over-cooked side servings. If for whatever reason you want to eat 100% raw, first of course you have to take a B12 supplement. Second, a diet based on modern cultivated fruits is not nutritionally adequate.They're a pale shadow of the wild fruits eaten by our ape ancestors. To improve the nutritional content, one would have to add at least a half kilo a day of dark green leafies, 5 to 10 cups and at least 50 grams a day of nuts and seeds, about half a cup. And third, i explicitly recommend against raw food diets for young children, as they just don't have the stomach capacity. Although an all raw food diet can be healthy, there is no reliable evidence to suggest that it's more healthy than a diet of whole plant foods, cooked or not.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by veganmontreal.
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