What is Caloric Restriction?

[Guest guest]

I am still thinking about the paper posted by Dowling

about Intermittent Fasting and caloric restriction.

http://snipurl.com/4d7w

Nobody commented on my post (Message 13677) which pointed out

what were some interesting facts in the publication, although there

have been some questions on terminology like " Is there such a thing as

non-intermittent fasting? " , to which the answer is: yes, it happens

after death.

But seriously, to make good use of Walford's ideas, I feel that one of

the hardest issues we have to address is knowing how much to eat (CR),

and there is also the problem of knowing what to eat (Optimum

Nutrition), but ON is a secondary problem.

In animal experiments, CR is defined as the percent of reduction in

food provided to a group of animals, compared to the amount of food

that a control group eats ad libitum. Typical experiments start CR at

an early stage in the animal's life. For mice, food is generally

provided ad libitum until 9 weeks of age, which would be the

equivalent to starting a CR program at the human age of 8. Because

the diet is well balanced, no nutritional deficiencies develop, and

the calorically restricted mice have extended life spans compared to

the ones that are not restricted. However, adult mice that are on

limited daily feeding regimens and consume 40% less food than those

that are fed ad libitum have 49% lower body weights. In human terms

this would mean that an adult person subjected to a CR diet from an

early age would weigh 76 pounds compared to 150 pounds for one whose

diet was unrestricted.

We all started our CR programs after reaching maturity. Therefore, we

are big compared to how we would be if we had started CR before

puberty. The growing body adjusts to CR by producing a smaller body,

just like a maple planted in a small pot will stay small and become a

bonzai. A small, 76-pound person will have smaller caloric

requirements than a 150-pound person and will be able to survive and

thrive on 40% fewer calories than the big person. What would happen

to the 150-pound person if he/she were placed on a 40% CR diet? The

results would probably be detrimental as mentioned in BT120YD.

To me it seems obvious that the calories consumed by adults should not

be below the number of calories required to support the base

metabolism and physical activity once a healthy BMI has been attained

(between 21 and 22). The consequence of consuming fewer calories,

once an optimum weight has been reached, means that some necessary

body tissues will be sacrificed and this loss may eventually lead to

health problems.

Intermittent Fasting (eating on alternate days) seems to provide the

long life that we seek, and this may be a better way of achieving

longevity than reducing the calories below those required by our base

metabolism.

Tony