Calorie restriction and body size

[Guest guest]

For some time, I have been reading posts in the Calorie Restriction

Society about people who start losing bone mass with severe CR. As

practitioners of Calorie Restriction, we need to be able to determine

how much CR is good, and how much can be harmful.

Yesterday, I made an entry in my blog with a graphic showing the

relative sizes of humans if they were raised on calorie restricted

diets like the mice. My blog entry has a link to a paper by Mattson.

I highly recommend looking at Figure 1 of the Mattson paper in

detail. It shows how 40% CR prevents the restricted mice from gaining

weight so that at maturity they weigh only half as much as the

controls. In human terms, a 150 pound adult control, would be matched

with a 75 pound individual raised on 40%CR.

http://www.scientificpsychic.com/blog/

I am becoming more convinced that exceeding 15% CR started in

adulthood may be more harmful than beneficial. PMID 15345727, below,

seems to confirm this view.

It is important to be able to determine %CR accurately. The new book

" The CR Way " by P. McGlothin, uses a way of estimating %CR by

referencing the average consumption levels determined by the Institute

of Medicine. This is a similar, but less customized approach, than

used by my CR calculator:

http://www.scientificpsychic.com/health/cron1.html

Tony

Willcox BJ, Yano K, Chen R, Willcox DC, BL, Masaki KH,

Donlon T, Tanaka B, Curb JD., How much should we eat? The association

between energy intake and mortality in a 36-year follow-up study of

Japanese-American men, J Gerontol A Biol Sci Med Sci., 2004

Aug;59(8):789-95.

Energy restriction extends life span and lowers mortality from

age-related diseases in many species, but the effects in humans are

unknown. We prospectively examined this relationship in a large

epidemiological study of Japanese-American men. We followed 1915

healthy nonsmokers, aged 45-68 years at study onset, for 36 years.

Twenty-four-hour recall of diet was recorded at baseline, and

follow-up was for all-cause mortality. After adjustment for age and

other confounders, there was a trend toward lower mortality in the

second quintile of energy intake, suggesting that men who consumed 15%

below the group mean were at the lowest risk for all-cause mortality.

Increased mortality was seen with intakes below 50% of group mean.

Thus, we observed trends between low energy intake and reduced risk

for all-cause mortality in humans until energy intake fell to less

than half the group mean, consistent with previous findings in other

species.

PMID: 15345727