Although not usually recognized, considerable protein destruction takes
place as foods are heated. This has been underscored by an editorial in
Nutrition News.

"It has been postulated the dry heat processing of proteins produces a
new lysine linkage which is either not digestible by enzymes or is so
slowly digested that lysine enters the blood stream too late to
participate with the rest of the assimilated amino acids in tissue
formation."

More severe heat damage to proteins results when moist heat is used.
When reducing sugars (e.g. glucose) are present, true destruction of
amino acids has been repeatedly corroborated. This destruction may
account for a loss of 50% of the lysine, arginine, tryptophan, and
histidine content.

Reference:
"Present status of heat-processing damage to protein foods". Nutrit.
Rev. 8: #7, 193-196, July 1950

A startling example of protein destruction during the cooking of food
was reported at the Mead Johnson Research Center in Evansville, Indiana.
It was discovered that the stockpile of survival biscuits and crackers
developed by the Office of Civil Defense for use in catastrophic
emergencies was significantly deficient in essential amino acid content.
Actually two-thirds of the lysine was destroyed presumably during the
baking of these foods.

Reference:
Longenecker, J. B. and Sarett, H. P. "Nutritional quality of survival
biscuits and crackers". Am. J. Clin. Nutrit. 13: #5, 291-296, November
1963.

I should also note that cooking creates carcinogenic and mutagenic
substances in proteins and fats. Cooked proteins and fats are full of
free radicals as well. Ingestion of cooked proteins and fats increases
entropy - accelerates the aging process, and contributes to a myriad of
disease processes.

Does anyone have any material indicating otherwise?

-- Wes