I would like to thank everybody who took the time and effort to reply to my question.  I've cut
bits and pieces from various e-mails and asked a few more questions, if that is OK?

> In rodent studies calorie restricted mice on high protein diets outlive ad
> lib controls and other high carb calorie restricted mice.

Do you have a reference for this study?

> What kind of animals? Rabbits or sheep? Dogs live longer on a paleo diet.

It doesn't say.  Here is my friend's original article, with the associated references:

http://www.eoffshore.com/mlaughlin/coppola.htm

> Any animal fed biologically inappropriate diet will live shorter. So if they
> feed rats diet of 50% protein no wonder they lived shorter.
> Such reseraches are quite easy to manipulate.
> My rats always eat proteins (meats, eggs, etc) first and that start to eat
> grains, fruits,etc.

I don't believe that any percentage was specified.

> The Inuits which ate up to 10 pounds of meat and fat a day was still able to
> reach 60-70 years in extreme weather conditions.

Do you have a reference for this study Paul?  60 years isn't that long, Dr. Walford expects to live
to 120.

> For many, the restriction of carbohydrates lowers insulin levels and
> decreases hunger, which eventually means caloric intake is reduced.
> Therefore, low carb diet can equate to a longer life.

Do you have any reference for your speculation that low carb diets lead to a longer life?  Is it
not also possible that excess protein can damage the cells or the organs?

> I don't think there are many people who could live on a reduced calorie diet
> all of their lives.

I know I can't.

>  I couldn't.  But decreasing carbs has removed my desire
> to overeat, and I know that I eat less calories, although not by will power.
> I'm just not as hungry.

I found that removing grains and dairy also curbed my hunger (I'm coeliac).

> If this is true (and I assume it is) I wonder why they ate so much. I read
> that they ate at least 5 times a day huge amounts and meat and fat and
> basically were described as 'always hungry' people.

Maybe most of their energy went towards heating the body, hence the constant hunger?

> Exactly, but I don't think anybody can answer it. It will be only
> speculations like lack of vit C, lack of sunshine, excessve protein,etc.
> Plus our medicine (we may critisize it) has many ways to prolong the life
> even if it means prolonging the misery.

I think double blind studies can help us to identify patterns that indicate more likely sources.

> But still life expectancy is the highest among people living in rather cold
> climats.

Do you have a reference for this?

Thanks,

Katrina.