Calorie Restriction & Longevity

[Cory Duchesne]

So it looks like you can make some animals live significantly longer and also more healthily by having them eat a good deal less than a test animal fed an ordinary diet. While this has been demonstrated to work in rodents, fish, and dogs, tests in primates are still ongoing, so scientists are very unsure whether this can be generalized to humans. There have been some limited, short-term tests in humans, though.

So far, the evidence is that a low calorie, high-nutrient diet tends to give people very strong improvements on cardiovascular risk factors, even more so than just ordinary healthy diet plus exercise. The people in the study lost a lot of weight, for obvious reasons, but they also saw their blood pressure lower quite dramatically, by twenty points or more in some cases. Such experiments may be mostly a theoretical exercise, as the majority of people would find it extremely hard to sustain the diet, but it is still interesting. No one knows exactly why calorie restriction has these beneficial effects in animals, but there are some theories, such as decreased levels of insulin.

 

[bokonon]

I believe it's probably true that calorie restriction confers longevity, but I'm not going to change my eating habits because of it. Even if I had enough willpower to go that route myself, I'm too vain to be willing to walk around emaciated just to live longer.

The research I've read suggests that it's really eating less that provides the benefit; simply trying to exercise off excess calories doesn't do it. I'll be interested in following new developments in the research, as I can't imagine what the metabolic mechanisms would be that produced this effect.

 

[Delvo]

live significantly longer and also more healthily

That latter part is new to me (and contradicts some theories for why the former happens). Where did that part come from?

 

[noreligion]

So it looks like you can make some animals live significantly longer and also more healthily by having them eat a good deal less than a test animal fed an ordinary diet. While this has been demonstrated to work in rodents, fish, and dogs, tests in primates are still ongoing, so scientists are very unsure whether this can be generalized to humans. There have been some limited, short-term tests in humans, though.

So far, the evidence is that a low calorie, high-nutrient diet tends to give people very strong improvements on cardiovascular risk factors, even more so than just ordinary healthy diet plus exercise. The people in the study lost a lot of weight, for obvious reasons, but they also saw their blood pressure lower quite dramatically, by twenty points or more in some cases. Such experiments may be mostly a theoretical exercise, as the majority of people would find it extremely hard to sustain the diet, but it is still interesting. No one knows exactly why calorie restriction has these beneficial effects in animals, but there are some theories, such as decreased levels of insulin.

How low calorie? Sounds like a very cruel experiment especially since the animals are not volunteers.

 

[sol invictus]

So it looks like you can make some animals live significantly longer and also more healthily by having them eat a good deal less than a test animal fed an ordinary diet.

I second Delvo's question. My impression - based on a very incomplete knowledge of this - was that these animals were in fact quite unhealthy, or at least pretty wretched. I recall that mice on such diets lose some of their fur, have reduced energy and sex drive, etc.

So if you'll be miserable and half-starved, but it will last a long time.

 

[casebro]

I suspect that during starvation, the body scavenges anything it can convert to energy. Including arterial plaque. I wonder if it dissolves it's own liver too? Or just all the fuels stored there.

I wonder if fat cells are destroyed too? I'd guess a biopsy would show clumps of nucleuss, because the body won't destroy those.

 

[leon_heller]

I've suffered from malnutrition a couple of times when I've been very ill with Crohn's disease. Fat and muscle are lost.

 

[Trakar]

I've suffered from malnutrition a couple of times when I've been very ill with Crohn's disease. Fat and muscle are lost.

In many of these diets, we aren't really talking about malnutrition, but minimal nutrition, the primary issue is to reduce or eliminate "excess" calories. At least that is my understanding.

 

[casebro]

I've suffered from malnutrition a couple of times when I've been very ill with Crohn's disease. Fat and muscle are lost.

Cells often shrink, but seldom die on a diet/ short term malnutrition. I do have a myopathy, my muscle cells will die when over used. So my biopsy shows a) white fibers at 70% instead of the usual 50%, plus b) 'pyknotic nuclear clumps", clumps of nucluses left from the died off red fiber cells.

But I do wonder about the amount of scavenging going on in long term malnutrition. Does the body dissolve cancers? Arterial plaque? Germs? more than usual?

 

[Professor Yaffle]

The Minnesota experiment showed there are severe psychological effects of semi-starvation. I wonder how far a calorific restriction diet would be (calorie-wise) from the conditions imposed in this experiment and whether similar symptoms would be experienced?

http://en.wikipedia.org/wiki/Minnesota_Starvation_Experiment
http://americanradioworks.publicradio.org/features/wwii/a1.html

 

[Trakar]

Cells often shrink, but seldom die on a diet/ short term malnutrition. I do have a myopathy, my muscle cells will die when over used. So my biopsy shows a) white fibers at 70% instead of the usual 50%, plus b) 'pyknotic nuclear clumps", clumps of nucluses left from the died off red fiber cells.

But I do wonder about the amount of scavenging going on in long term malnutrition. Does the body dissolve cancers? Arterial plaque? Germs? more than usual?

Interesting question!?

 

[Trakar]

In reading upon one of the more fringe "life-extension" reduced diets, I ran across the following paragraph that seemed designed to share:

There are some ethical problems in applying calorie restriction protocols to humans because food restriction has been used as a punishment throughout history and food deprivation associated with famines and concentration camps evokes very negative images. To emulate the mice experiments, calorie restriction of humans would need to start around 2 or 3 years of age and provide all necessary nutrients. A fully-grown human adult raised on a 40% calorie restricted diet would weigh 75 pounds instead the normal 150 pounds. Presumably such humans could live to an age of 120 years under ideal conditions, but their small size, equivalent to that of a 10-year-old child, would be a serious social disadvantage in any confrontation or competition requiring physical strength and stamina. It is not known whether smaller humans with smaller brains would have the same mental faculties or be as intelligent as their bigger counterparts, and there are also unanswered questions about various aspects of reproduction.

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

cool!
Eloi!

(mmmmm, eloi!)

 

[noreligion]

In readin gg upon one of the more fringe "life-extension" reduced diets, I ran across the following paragraph that seemed designed to share:



cool!
Eloi!

(mmmmm, eloi!)

I am also sure these "reduced" humans (subhumans?) would be ideal for forced labor in some kind of camp and they would be cheap to keep. Why does this research smack of a Joseph Gobbels air?

 

[Trakar]

I am also sure these "reduced" humans (subhumans?) would be ideal for forced labor in some kind of camp and they would be cheap to keep. Why does this research smack of a Joseph Gobbels air?

Arrghh, there I'm trying to make a perfectly reasonable cannibal allusion and you Godwin me!

Is there no decorum left within these halls!!!

 

[JoshNankivel]

I just posted a book review on "Catching Fire" (not posted yet, in moderation) - in that book there is a discussion about how a raw food diet has been shown to decrease sexual health in particular since we can not extract as many calories from most raw food as we can cooked food. Women can stop menstruating, sex drive decreases in both genders, etc.

I think it's important to understand that even if caloric restriction may lead to a somewhat longer life (I am dubious, especially on the scope of what "longer" really means) there are other factors here.

Longevity is not the only goal for well-adjusted people. We also want to feel good, have plenty of energy, a healthy sex life, etc. For me, portion control is important but only to the extent where I am still satisfied after meals AND can maintain it for the long-haul. As soon as you throw the word "restriction" in there it sounds to me like something you would never do long-term anyway.

One more point: someone mentioned that the longevity increases could come from just reduced caloric intake; not a look at net calories with exercise included. I would just add that exercise has it's own health benefits that you won't get from caloric restriction alone; enough that I would argue exercise at some level is always a good thing (and you need enough calories to do it!)

-Josh, pmStudent.com

 

[casebro]

"It's not how many breaths you take,
It's how many times you have been breathless that counts."

 

[Lukraak_Sisser]

I'm sure this has been discussed here before, but as others have mentioned, this low nutrition diet would for most humans probably be extremely unpleasant. Not to mention that these experiments are done on laboratory animals that do not need to work and are not exposed to the immense host of diseases that humans are. And the effects of malnutrition on the immune system are not good.
Furthermore, laboratory animals do not recieve healthcare that is comparable to what most humans in the west recieve, which has already more than doubled our normal life expectancy. And there is absolutely no guarantuee that such a diet would prevent you from getting the general age related problems. If someone is willing to starve themselves for their entire adult life (doing this to children would be cruel) just so they can sit in a retirement home being unable to truly do something for a year longer, I'd say more power to them.

 

[quarky]

Being hungry, but not mal-nourished, is where its at.

 

[Trakar]

(...)

Longevity is not the only goal for well-adjusted people. We also want to feel good, have plenty of energy, a healthy sex life, etc. For me, portion control is important but only to the extent where I am still satisfied after meals AND can maintain it for the long-haul. As soon as you throw the word "restriction" in there it sounds to me like something you would never do long-term anyway.

One more point: someone mentioned that the longevity increases could come from just reduced caloric intake; not a look at net calories with exercise included. I would just add that exercise has it's own health benefits that you won't get from caloric restriction alone; enough that I would argue exercise at some level is always a good thing (and you need enough calories to do it!)

-Josh, pmStudent.com

Additionally, there seem to be benefits at all levels of caloric restriction. Given the tradeoffs most of us would want to associate with longer existence. modest reductions can make us healthier, which in itself would seem a reasonable goal and end all unto itself.

 

[Professor Yaffle]

Additionally, there seem to be benefits at all levels of caloric restriction.

Well.....not quite all levels...