A Note on Fasting

[Guest guest]

Hi folks:

There is not a lot of information, it seems to me, about how the

health benefits of fasting as a means of caloric restriction compare

with eating smaller amounts on a more or less continuous basis.

Especially in humans. But the following basic data may be worth

bearing in mind.

Normal eating schedules entail overnight fasts of from ten to

fourteen hours. Ten hours if no food is eaten from 8pm to 6am.

Fourteen hours if no food is eaten between 6pm and 8am.

One step up from that degree of fasting would be to eat just one meal

each day at the same time. Assuming that the eating period lasts two

hours, then the fasting period is 22 hours, seven times a week.

One further step up from that might be eating normally one day and

eating nothing the next. This entails a 34 hour fast - from,

perhaps, 8pm Tuesday to 6am Thursday, for example, three or four

times a week.

Interesting, though, is the fasting involved in CRON experiments in

mice where, not infrequently, they are fed in the early am, Monday,

Wednesday and Friday. Assuming the restricted mice finish their

rations within six hours of receiving them, then each week this

entails two fasts of 42 hours, and one of 66 hours each week: from

3pm Monday to 9am Wednesday; from 3pm Wednesday to 9am Friday; and

from 3pm Friday to 9am Monday.

The mice live a lot longer while doing the fasting in this last

example. fwiw. But of course humans are not mice.

Rodney.

[Guest guest]

First, let's decide if we're doing it to lose weight. If not, we might be concerned about the rate of nitrogen loss, "initially high (11-23 grams/day)" MNHD, pg 1409.

"After an overnight fast, insulin levels drop enough to stimulate mild net muscle proteolysis thereby releasing amino acids....... In a fast longer than a day insulin secretion drops yet further, muscle proteolysis is more strongly stimulated and considerable skeletal muscle protein is lost." pg 648-49.

So I might skip a day if I wanted to lose weight. If not I think I would eat some every 24 period.

So the question is how do I use that mechanism in CR? We've read comments in CR we need to eat more protein. That would indicate we want to lose less nitrogen.

Also, it occurs to me a day for a rat is a lot longer than a day for a human.

So what happens in the rat (the equiv of several days in a human)? The human nitrogen loss begins to adapt after 7-12 days, to half the early rate in 2-3 wks.

Lots more on pg 649, but the point is we don't know a lot about why.

"As ketone bodies replace glucose as the brain's oxidative fuel, the requirement for amino acid conversion to new glucose molecules is dramatically reduced."

And there perhaps lies why some like a low carbo diet.

OTOH, I have no idea what the metabolism of the rat is compare to a human. One day may not be a long fast for a rat.

Regards.

[ ] A Note on Fasting

Hi folks:There is not a lot of information, it seems to me, about how the health benefits of fasting as a means of caloric restriction compare with eating smaller amounts on a more or less continuous basis. Especially in humans. But the following basic data may be worth bearing in mind.Normal eating schedules entail overnight fasts of from ten to fourteen hours. Ten hours if no food is eaten from 8pm to 6am. Fourteen hours if no food is eaten between 6pm and 8am.One step up from that degree of fasting would be to eat just one meal each day at the same time. Assuming that the eating period lasts two hours, then the fasting period is 22 hours, seven times a week.One further step up from that might be eating normally one day and eating nothing the next. This entails a 34 hour fast - from, perhaps, 8pm Tuesday to 6am Thursday, for example, three or four times a week.Interesting, though, is the fasting involved in CRON experiments in mice where, not infrequently, they are fed in the early am, Monday, Wednesday and Friday. Assuming the restricted mice finish their rations within six hours of receiving them, then each week this entails two fasts of 42 hours, and one of 66 hours each week: from 3pm Monday to 9am Wednesday; from 3pm Wednesday to 9am Friday; and from 3pm Friday to 9am Monday.The mice live a lot longer while doing the fasting in this last example. fwiw. But of course humans are not mice.Rodney.

[Guest guest]

First, let's decide if we're doing it to lose weight. If not, we might be concerned about the rate of nitrogen loss, "initially high (11-23 grams/day)" MNHD, pg 1409.

"After an overnight fast, insulin levels drop enough to stimulate mild net muscle proteolysis thereby releasing amino acids....... In a fast longer than a day insulin secretion drops yet further, muscle proteolysis is more strongly stimulated and considerable skeletal muscle protein is lost." pg 648-49.

So I might skip a day if I wanted to lose weight. If not I think I would eat some every 24 period.

So the question is how do I use that mechanism in CR? We've read comments in CR we need to eat more protein. That would indicate we want to lose less nitrogen.

Also, it occurs to me a day for a rat is a lot longer than a day for a human.

So what happens in the rat (the equiv of several days in a human)? The human nitrogen loss begins to adapt after 7-12 days, to half the early rate in 2-3 wks.

Lots more on pg 649, but the point is we don't know a lot about why.

"As ketone bodies replace glucose as the brain's oxidative fuel, the requirement for amino acid conversion to new glucose molecules is dramatically reduced."

And there perhaps lies why some like a low carbo diet.

OTOH, I have no idea what the metabolism of the rat is compare to a human. One day may not be a long fast for a rat.

Regards.

[ ] A Note on Fasting

Hi folks:There is not a lot of information, it seems to me, about how the health benefits of fasting as a means of caloric restriction compare with eating smaller amounts on a more or less continuous basis. Especially in humans. But the following basic data may be worth bearing in mind.Normal eating schedules entail overnight fasts of from ten to fourteen hours. Ten hours if no food is eaten from 8pm to 6am. Fourteen hours if no food is eaten between 6pm and 8am.One step up from that degree of fasting would be to eat just one meal each day at the same time. Assuming that the eating period lasts two hours, then the fasting period is 22 hours, seven times a week.One further step up from that might be eating normally one day and eating nothing the next. This entails a 34 hour fast - from, perhaps, 8pm Tuesday to 6am Thursday, for example, three or four times a week.Interesting, though, is the fasting involved in CRON experiments in mice where, not infrequently, they are fed in the early am, Monday, Wednesday and Friday. Assuming the restricted mice finish their rations within six hours of receiving them, then each week this entails two fasts of 42 hours, and one of 66 hours each week: from 3pm Monday to 9am Wednesday; from 3pm Wednesday to 9am Friday; and from 3pm Friday to 9am Monday.The mice live a lot longer while doing the fasting in this last example. fwiw. But of course humans are not mice.Rodney.