Lifestyle food cults abound often tying themselves to one idea thought to
trump all other considerations in nutrition. The raw food example is one
such where the assertion is made that cooking destroys nutritional
elements and food is best eaten raw, very often tied to not including meat
either raw or cooked. Here is a bit from a newsletter to which I
subscribe outlining the topic:
"Many people believe that fresh fruits and vegetables always contain
more nutrients than cooked ones, but cooked carrots have higher
levels of antioxidants than fresh carrots. Cooking carrots in the
presence of a small amount of oil or butter increases the amount of
two antioxidants called beta carotene and phenolic acid. Cooking also
increases the amount of lycopene you get from tomatoes. Cooking
breaks the plant cells open to increase the absorption of these
antioxidants and other beneficial plant chemicals. Adding a little
oil or butter increases absorption of fat soluble chemicals. Some
vitamins are affected by cooking, but you'll still get plenty. The
enzymes in food that are destroyed by heat are of no use to you; your
body makes the enzymes you need to digest your food. Most of the
nutrients in food (minerals, proteins, fats, carbohydrates) are not
destroyed by heat, and many common foods are unpalatable or unsafe if
they are not cooked. I recommend eating the widest possible variety
of fruits and vegetables, raw or cooked, and fresh, frozen, canned or
dried."