Caloric Restriction Discredited

The CRON group is pretty fascinating, actually. If you show up on one of their forums with the intent to lose weight, people will sort of pounce on you and tell you you're in the wrong place. They're very hair-trigger about this.

However if you join and sort of keep your mouth shut, one great thing about them is that they are a fountain of information - a serious overflowing torrent of knowledge.

These people read and tend to have a greater understanding of actual scientific studies and body chemistry than any nutrition-oriented group I've ever been involved with (and they ask a LOT of questions of the scientists in the...movement, group, whatever you want to call it).

Nor do they have homogenous views on anything related to low fat vs. low carb or whatever. They are far more skeptical even of their own points of view than criticism of them would indicate. Their numbers (cholesterol, blood pressure) are impressive by any standard.

One of the ideas some of them have is that if they can live long enough, it is conceivable that the problems related to the idea that certain foods are life-shortening might be otherwise eliminated; in other words - live to 105, and they might have figured out a way of curing inevitable mortality altogether (I do think this will eventually happen, for better or worse - it's just chemistry), or they will find a supplement you could take which would make, say, eating a bunch of cheese, a benign activity. Or find something which eliminates craving for unhealthy foods altogether.

Sci-fi stuff to be sure but a generation ago the sequencing of the human genome was pretty far out. And as to "living life to its fullest," they see giving up certain foods in exchange for a 120 year lifespan more than worth it. I'm not sure I agree, but I don't think their position here is at all unreasonable. If they are right, they may get to know their great-great grandchildren, and live to see human colonization of space, and all of the things that might happen in the future (or the apocalypse - probably unpleasant, but what a light show!). For many life-extension people (CRON or otherwise) the goal is living long enough to have the entire problem of death by old age completely eliminated by science. I don't think, given the present pace of science, this is as far-out as some seem to think.

Like I say; it's just chemistry.

Second, it is not fully true that all of their studies have to do with rodents. If they have a "guru," it is a fellow by the name of Roy Walford, who was one of the Biosphere participants, who monitored the effects of a mandatory low calorie diet (as a result of not producing enough food inside Biosphere) on participants and found some exciting results. Of course these were only indirectly related to a long life span based on various markers.

Lastly, CRON people, being more scientifically oriented than most others I've personally encountered, are skeptical about the rodent studies. They don't claim their theories as the truth but as a possibility exciting enough and possible enough that a CRON lifestyle is a worthwhile gambit.

The problem is there hasn't been a long-term calorie restriction study on human longevity just because it hasn't been around as an idea long enough (at least in terms of a regimen; there have of course been scattered individuals here and there who have talked about it for a long time), and humans have long life spans. We won't know for another 40 or 50 years, probably, whether the CRON people are right, but if they are, it's going to make their regimen more attractive. Right now it's giving a lot up for a "maybe," - but if in the future it's giving a lot up for a "probably," well..you can see how this becomes more attractive. I'm sure many of them would agree with the idea of nothing ventured, nothing gained.

Their idea here is that they're hedging their bets - that even if CRON doesn't work, they're likely to be healthier in old age anyway, and that they're willing to make sacrifices now in hopes that the studies that do exist turn out to represent the general trend. I've never really detected any kind of unreasonable expectation that CRON will definitely work. Most of them are not sure, but there's enough evidence that they consider it worth trying.

The CRON mailing list is worth joining just to keep you up to date on the latest nutritional studies, the summaries of which are typically presented in a much more nuanced way than the "quickie summaries" you read in major news sources which are often misleading or overly-simplified. Even if you have no interest in CRON, the amount of information, often straight from the source (Medline, medical journals, etc.) makes subscription worth it. Sometimes the discussion is at such a low (scientific) level I have trouble following it.

Whatever you do though, just don't mention that you're interested in losing weight :)

The CRON people are not in general fanatic about the "religious truth" of their practice the way, say, Atkins people tend to be when they cluster in groups. There is an unusual amount of healthy skepticism, and those fully invested in the lifestyle are pretty clear about the disadvantages (one guy lost all interest in sex (he's married), and the constant obsession with food is clearly documented).

Reading outside commentary about the CRON group though, one would assume they're just another group of diet fanatics. To some extent they are, but they're way more honest about it than most. There's a lot to be learned from these folks if you're into general nutrition, weight loss, or theoretical life extension.

All of this being said, while I'd like to live a long time, I'm mostly interested right now in losing weight. The basic calculus of Eat less exercise more / Expend more calories than you consume, seems to be correct, but other diets, including CRON, can yield wisdom as to how to make this simpler (if you don't eat a lot of high glycemic load food, you'll be less hungry and probably eat less). One thing CRON people are constantly involved with is dealing with hunger, as you might imagine.

(I would add that calorie restriction may not be as radical as the unfamiliar might assume. The calorie restriction level is just lower than the numbers you normally hear - for example, if you are a moderately active 6 foot tall male, 1800 calories a day would probably fall under the category of calorie restriction (2200 or thereabouts is what's recommended by most "health authorities" and online calculators); that's hardly total deprivation. They also stress, and are obsessed with, the "ON" - Optimal Nutrition part of "CRON" - so this is not an anorexic's diet. This is about eating for maximum nutritional density. Unlike other diets, especially since weight loss is not the primary issue - CRON places equal emphasis on nutrition rather than treating it as a secondary afterthought as most diets do.)

For those of us with high blood pressure, high cholesterol, etc. there's a lot you can learn from listening to CRON people. Since in general, being lean, having low blood pressure, and low cholesterol is likely to lead to a longer life, these are also of interest to the CRON folks, who are a great source of information on prevention.

I don't practice CRON (to do that I'd have to eat restricted calories forever, and not for weight loss but life extension) but I guess I'm saying they have a lot more to contribute than their critics might suggest. I've been on low-fat lists, low-carb lists, various newsgroups, and sites like this one, and in terms of raw information and hard facts and science, nothing comes anywhere close to the CRON mailing list.

I'm curious how many people involved with it would consider it "misery." It's like saying that working long, long days at NASA because someday you "might" be involved in getting a probe landing on Mars is misery. It's a gamble, a risk, a sacrifice, for a potentially awesome - awe-inspiring - reward - an unusually long life.

In my effort to drop some weight I'm eating what would technically be acceptable as a CRON diet (though as I say, I'm not doing it for life extension). It involves some sacrifice, but it's hardly misery. I still eat 3 square meals a day, just smaller ones and a whole lot more vegetables than I would if I didn't need to drop weight. This is what CRON people do.

For the CRON people at least, the rule is - eat the minimum amount of calories necessary to consume 100% recommended nutrition. I am sure that most still like a little honey in their tea from time to time.

Caloric restriction, in addition to being poorly understood by biologists in its mechanism of function, has not, and cannot bring to humans and large mammals the same results found in rodents. It's all in the numbers, however, from how caloric restriction works to why it doesn't work on large mammals, that is, those over 10 kilograms. The numbers are found in the quarter power scaling equation relating metabolic rate/life span potential to body mass and its exponent, which includes a variable for metabolic efficiency - the rate of ATP synthesis divided by the rate of electron flow from food sources. Differences in mitochondrial densities and efficiencies, from the cells of shrews to those of mice to those of humans and whales, explains why caloric restriction works on shrews and mice, and why it won't work on cows, humans, porpoises and whales. But you'll never read about it in any science mag because it is in the province of what is called 'mathematical biology', an area which many biologists, physicians, and pretenders to scientific authority like clinical neurologists, avoid for its scientific rigor.

The effectiveness of CRON at extending maximum lifespan is an experimental question, and you may have the wrong answer. Putting forth a simplistic model of a system which is itself poorly understood, and insisting it take the place of rigorous experimentation, smacks of hubris. I would propose an alternate reason for "pretenders to scientific authority" having ignored such input: finely crafted mathematic models are smashed to shards by reality all too often... ask any physicist. There have, in all fairness, been good mathematical models done (Phelan) that indicate the benefit of CRON in humans will be slight. Once again, such studies have been wrong before; modeling is one thing, experimental proof is an entirely different one. As to the question of CRON itself, it will likely extend the lives of practitioners, regardless of whether or not it extends the maximum human lifespan (these are not the same thing). With obesity rivaling tobacco as the leading cause of preventable death (source: CDC - no doubt "pretenders to scientific authority"), a diet like CRON can make sense. As Iggy pointed out, bloodwork from CRONers is astonishingly good for markers like lipid profile. A CRON diet is also high in fiber, fruit, and vegetables, and low in meat and fat. This is in accordance with the ACS Guidelines for Eating Well and Being Active (American Cancer Society). I wonder what your slide rule would say about the life expectancy of a non-obese, non-diabetic, non-hypertensive, non-smoker, who has a cholesterol of 127, and who consumes a diet that meets 100% of nutritional requirements every day of their adult lives. Based on the very large body of modern medical evidence, and CRONer's bloodwork, CRONers will have at the very least reduced their chances of premature death due to the leading preventable causes. In fact, CRONers are showing good results on several ageing biomarkers. If all CRON does is keep you fit and youthful longer, it has already done something worthwhile. And, the jury isn't out yet on the rest.

I really liked the comments by Iggy Petulante and lrfiv.

A little over 2 years ago (April, 2004) I decided I wanted to lose weight. I spent time reading up on various diets and stumbled upon Calorie Restriction (CR). I was impressed with the amount of scientific evidence for it, as opposed to the other diets.
So I tried it. I had no problem with cutting the calories, but tracking the nutrients was a major hassle.

I lost 30 lbs in short order (1 to 2 lbs per week) and stuck with the diet for a little over a year. I learned a tremendous amount about nutrition. A got away from the diet for 6 months, gained back 10 lbs.

Since January, 2006 I have been back on the diet, quickly losing the 10 lbs.

The evidence supporting the diet continues to build, with 3 clinical studies of humans being reported this year so far. Of course nothing definitive can be said about CR extending maximum human life span.

What can be said is that in other species where CR has significantly lengthened the life span, there are also "biomarkers" (values for various blood tests and so on) that characterize the CR animals and not the controls. The accumulating evidence is that the equivalent biomarker results are occuring in people on CR and not in those who are not on CR, just as in the case of other animals.

As Iggy said, whether or not you get the maximum life extension, you do get the secondary aging benefits - much less disease, much healthier. My email is phillips@kcnet.com, I do not mind it being posted.

As usual, another uninformed critic of CRON.

Everyone I know who practices CRON, myself included, is happy, fulfilled, and healthy. Why don't you find out some more before you cast aspersions on people you've never even met?

Check out my blog for how life can be fun, healthy, and delicious *while* taking advantage of the only known intervention to extend life in mammals.

Will it work in the long term? Nobody knows. I am participating in a study to follow our progress. But I do know that I feel great, look great, never get sick, and enjoy every minute of my life in the here and now. I'd much rather live this way than go back to eating ad lib.

If it's not for you, fine. But don't dismiss those of us who find this to be a very satisfying lifestyle until you find out a little more.

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