>
> In 1838, in Canada, Dr. William Beaumont performed a remarkable series of
> experiments on a man named Alexis St. Martin. St. Martin had an opening in
> the front wall of his stomach from a gunshot wound. Even after the wound had
> healed, there remained a small opening through which the mucous membrane of
> his stomach could be seen and, through which, substances could be introduced
> into the stomach or removed from it. Dr. Beaumont was able to introduce
> foodstuffs through the opening and observe the rate of digestion. By so
> doing, he found that raw beef digested in two hours, well done boiled beef
> in three hours but well done roast beef took four hours. Similarly, raw eggs
> were digested in one-and-a-half hours but hard-boiled eggs took
> three-and-a-half hours.

Before Todd Moody posted, I was about to ask how this constitutes scientific
evidence.

We have one study.

Performed on one man.

The man had a gunshot wound in his stomach.

Substances were introduced to his stomach through the hole in it, not via
chewing and swallowing.

Consequently, this study can't tell us much about normal digestion.

Besides being (to my knowledge) uncorroborated, it has these flaws:

The sample size too small.

The subject had major damage to the organ being studied, so it won't
necessarily give an accurate account of what happens in an undamaged
stomach.

Skipping the mastication further distances this study from digestion in
normal humans.

Moreover, this study seems focussed only on measuring how long each item
remained in the stomach. Very little actual digestion occurs in the stomach.
That the raw food was passed to the small intestine more quickly does not
mean it was more thoroughly digested, or that more nutrients were
assimilated from the raw than from the cooked.

This study didn't examine what happens after the stomach, in the small
intestine, where most digestion occurs. The raw food might spend half as
much time in the stomach and twice as much time in the small intestine,
compared to cooked food. In the end then there'd be no difference.

Another possibility is the raw food is passed through so quickly there is
reduced assimilation. If that were so then you have to eat more raw food
than cooked to get the same nutrition.

Passing quickly isn't necessarily always good sign. If you eat a poison it
may pass quickly also--you get diarrhea as a result. Faster movement thus
may represent the body rejecting the food.

Enough said. I'm not making conclusions, just pointing out that this study
has many flaws and the conclusions often drawn do not follow inexorably.

Don