Obesity as Harmful to Longevity as Cancer

In the midst of a pessimistic article about future trends in life span (that fails, like most, to consider the effects of current technological development on historical and short term trends) we find this item for consideration:

Obesity, [Olshansky] said, is "a global pandemic" that's already reduced life expectancy worldwide by 3.5 years. The effect of obesity on longevity is about the same as cancer, he said, and will double or triple in coming years, shortening lives by seven to 12 years.

Now I certainly don't agree with most of Jay Olshansky's propositions. His views on the possibility of increases in life span through directed medical research into the aging process are very unreasonable and he has not yet defended them in a rigorous fashion.

EDIT: Just to be clear here, I'm not disagreeing with Olshansky's conclusions regarding obesity and its effects on life expectancy, or calling into question this piece of research. What I do take issue with are his representations in the media regarding the dim prospects for healthy life extension through medical research. I - and to a lesser extent the scientists below - are skeptical about a decrease in overall life expectency because we expect to see gains due to advances in medicine.

Even other scientists who are not looking towards a future of radically increased healthy life spans are criticizing the projections made in this article:

"The modern era of dramatic increases in life expectancy is about to come to an end in the developed world - including the United States - as well as in the underdeveloped world," said Jay Olshansky, a demographer at the University of Illinois in Chicago.

"Life expectancy might very well decline in this century," he told last month's annual meeting of the Institute of Medicine, a branch of the National Academy of Sciences in Washington.


"Biology can play out quite differently in different countries at different times," said Richard Suzman, associate director of the Institute of Aging at the National Institutes of Health.

"Jay Olshansky's position is a minority perspective in demography," Suzman added. "However, majority positions in science sometimes turn out to be wrong, and so minority positions should certainly be entertained."

"There is a small chance - less than one in 100 - that Olshansky's prediction of declining life expectancy might possibly prove correct," Vaupel said.

Another skeptic is James Oeppen, a researcher at the Cambridge Group for the History of Population and Social Structure in Cambridge, England.

"If Dr. Olshansky is correct, he won't have to share the accolades with a large group of like-minded contemporaries," Oeppen scoffed.

Still, one cannot argue that excess weight in the form of body fat has been shown to be very harmful to your long term health. It greatly raises the risk of suffering all of the most common age-related conditions, shortens your healthy life span and increases your medical costs. I think that pointing out the comparison to cancer in terms of effect on life expectency is a powerful motivating argument. It's certainly something to think about if you are one of those people who needs that extra something in order to work towards better diet and lifestyle choices.


Dr. Olshansky still doesn't get it. Or perhaps he is trapped within his own rhetoric. If the majority of people let themselves become fat, the average life expentancy will definitely go down. This has no impact, whatsoever, apon the life expectancy of someone who chooses not to become fat and practices sound techniques of life extension. You choose whether to become obese or not. You choose whether to screw around alot or not and end up with AIDS. This stuff is completely preventable.

Look up Dr. Olshansky's biography. This guy has his PhD in sociology. He is not technical. He is not qualified, technically, to say if it is technically possible to cure aging or not.

Forget about Dr. Olshansky. He is among the chattering classes that know nothing of what they talk about. People like him are idiots.

Posted by: Kurt at November 6th, 2004 10:07 PM

True, which is why we have to keep calling him on it every time he ends up in the press. Public support for serious anti-aging research is vital, and while researchers in the field don't listen to Olshansky, a bunch of other people do.

Posted by: Reason at November 6th, 2004 10:19 PM

Indeed. Olshansky might as well be on the side of Leon Kass for all I know. Actually placing a bet that anti-aging technologies won't be developed in the next century is beyond ludicrous. Hopefully the aging of the Baby Boom would prove him wrong.

Posted by: adbatstone at November 7th, 2004 1:45 AM

Greetings readers of Reason. I came across this line of arguments recently, and was surprised to see this story about my presentation at the Institute of Medicine. A couple of things are worth noting. First off, all of the comments on the topic in this string, including those posted by Reason, have been made by those who have not read the manuscript. Perhaps it would be wise to hold your opinion on the validity of our arguments until you see the evidence. Second, the manuscript has 9 authors representing names you'll recognize in the fields of aging, obesity, biology, and infectious diseases. It is incorrect to attribute the conclusions entirely to the first author. Third, I'm not sure where anyone got the idea that I do not think anti-aging interventions are worthwhile or forthcoming. If you saw my presentation at the last annual meeting of the Gerontological Society of America, you would know that I present a very strong argument in favor of anti-aging interventions and research. Finally, for Kurt who proclaims to know my training, perhaps it would be wise to dig a bit deeper -- it is evident he's not aware of what I've been doing for the past 10 years.
Please keep up the dialogue though, for open debate on these topics is what I find most enjoyable about science.
S. Jay Olshansky

Posted by: S. Jay Olshansky at November 10th, 2004 3:09 PM

I read through the original posting on this topic and noticed a couple of other things. First, the author stated that we failed to "...consider the effects of current technological development on historical and short term trends." How would the author know this -- he/she has not read the article?

Second, the following quote appears:

"Now I certainly don't agree with most of Jay Olshansky's propositions. His views on the possibility of increases in life span through directed medical research into the aging process are very unreasonable and he has not yet defended them in a rigorous fashion. Even other scientists who are not looking towards a future of radically increased healthy life spans are criticizing the projections made in this article."

What views is the author referring to? Also, the other scientists criticizing our views in this manuscript have not even read it yet -- how can such comments be made? Furthermore, in our position statement, which was signed by 51 scientists, we state the following:

"We enthusiastically support research in genetic engineering, stem cells, geriatric medicine and therapeutic pharmaceuticals, technologies that promise to revolutionize medicine as we know it. Most biogerontologists believe that our rapidly expanding scientific knowledge holds the promise that means may eventually be discovered to slow the rate of aging. If successful, these interventions are likely to postpone age-related diseases and disorders and extend the period of healthy life. Although the degree to which such interventions might extend length of life is uncertain, we believe this is the only way another quantum leap in life expectancy is even possible. Our concern is that when proponents of antiaging medicine claim that the fountain of youth has already been discovered, it negatively affects the credibility of serious scientific research efforts on aging. Because aging is the greatest risk factor for the leading causes of death and other age-related pathologies, more attention must be paid to the study of these universal underlying processes. Successful efforts to slow the rate of aging would have dramatic health benefits for the population by far exceeding the anticipated changes in health and length of life that would result from the complete elimination of heart disease, cancer, stroke and other age-associated diseases and disorders."

This is an explicit statement that we think anti-aging interventions are not just worthwhile, but also highly desirable.

I think the author of the Reason article should identify him/herself -- I believe this biased reporting of science and lack of scholarship should be made visible. Is the author willing to reveal his/her name??
S. Jay Olshansky

Posted by: S. Jay Olshansky at November 10th, 2004 5:17 PM

Just for the record, my full, legal and only name is Reason - it's a long story, and I won't bore you with it. I'll respond to your other comments a little later.

Posted by: Reason at November 10th, 2004 5:50 PM

Reason, please bore us with the long story. I myself have been curious for a while, as most others with single-name handles have at times dropped their "real" full names. I'm curious as to why your full, legal name is Reason.

Okay, off-topic chatter aside, I think Kurt hit the nail on the head.

>If the majority of people let themselves become >fat, the average life expentancy will >definitely go down. This has no impact, >whatsoever, apon the life expectancy of someone >who chooses not to become fat and practices >sound techniques of life extension.

In light of what Kurt said, I think S. Jay Olshansky's paper may be in some respects correct.

"Life expectancy" is this nebulous term. It at once describes the mean life expectancy of people yet to die, extrapolated from data on people who have died, and it describes an approximation of what age someone might expect to live to if they were "average". Note that the former use of the term is scientific/mathematical (the "mean", a precise statistical term) and the latter is a broad generalization, not quite scientific.

Someone who is "average", what is that? In the coming years, it is expected to be someone much more obese than someone who is "average" today. Given the lag time until advanced new treatments are developed and brought to mass market, there is a good possibility that the average age of people DYING in a given year will take a momentary dip in the coming couple decades before this "quantum leap" of which Olshansky talks about takes effect and pushes the mean age at death back up.

Note that this is a statistical analysis of people who are dead, not people who are alive. We should not assume that this momentary dip in life expectancy actually applies to someone born in a particular year in the near future. This dip in life expectancy will probably only really apply to people who are already elderly and near death anyway. It doesn't apply to the whole populace in general, because that "quantum leap" in medical technology will come in time for the younger populations to counter the very real health consequences of our ballooning (literally) population.

Additionally, this momentary dip doesn't apply to the age someone could reach if he took care of himself properly. That "life expectancy" figure should continue to climb, as obesity will not be an issue. And this, unfortunately, is the "life expectancy" figure that should matter when discussing aging and anti-aging science.

Now I will refrain from making judgements on Olshansky's paper, because I do not know which L.E. figure was the appropriate one to discuss. However, in the broader picture of aging and anti-aging science, Olshansky and others should take care to quote the correct L.E. figure: the one of someone who takes minimal good care of himself, i.e. not becoming obese, smoking, drinking heavily, etc. I'm not going so far as to say we should be quoting the L.E. figures of CR'd, exercising people (not that we have accurate ones yet), just people following normal dietary guidelines, etc.

Posted by: Jay Fox at November 11th, 2004 9:39 AM

Jay Fox: Your intuition is correct. The measure of life expectancy is not based on an average -- it is built upon the assumption that death rates at all ages in a given time period (usually one year) will apply to everyone currently alive. So, when we say that period life expectancy at birth for females in the U.S. in 2004 is 80.0 years, this assumes that female babies born today in the U.S. will experience throughout their lives, the mortality risks present at every age, of females in the year 2004. Under conditions of declining mortality, period life expectancy is an underestimate; under conditions of rising mortality, it is an overestimate. As an example, period life expectancy at birth for U.S. females in 1900 was something like 45.0 years. The actual life expectancy for the female birth cohort of 1900 was something like 48 years -- a 3-year underestimate in this case. Remember that the measure of life expectancy does not apply to individuals.

You also raise another useful point. The gain in period life expectancy that would occur with the elimination of cancer would be much greater for people with cancer, than it would be for the entire population. The reason for the lower gain for the population should be obvious -- only a portion of the total population is at risk of dying from cancer. I work with life expectancy at the population level, and that is what all of my published work to date has dealt with, so you're correct in recognizing that the numbers I'm talking about do not apply to subgroups of the population (such as those following CR or some other dietary regimen).

Calculating the impact of a given intervention, such as CR, on the life expectancy of those who have adopted such a lifestyle, is not a simple matter. Not only will the numbers of people on the diet have to be large enough to yield reliable age-specific death rates in order to generate a life table, you would have to wait until most have died before you can generate such a life table (i.e., we would be calculating the life expectancy of a cohort). We might be able to gauge differences in the risk of death within a given range in the short term, but the answer to its possible impact on life expectancy will have to wait until the data are available.

Again, as a reminder, to date I have always dealt with the life expectancy of a population --a point we always make explicit in our manuscripts.
Good question Jay.
S. Jay Olshansky

Posted by: S. Jay Olshansky at November 12th, 2004 8:14 AM

I beleive, considering the statements of many of the experts, that obesity is a problem that not only needs to be takin more seriously. But to take action in more ways than one. For example, instead of making a Mc'Donalds commercial make a health awarness commercial concerning the life span of an obiess person. Please disragard my spelling errors, I'm only 15.

Posted by: Chris Quinn at December 7th, 2004 6:35 PM

Obesity is a very big problem indeed for some countries. However it's underestimated. It also kills us, though not so evidently. It also affects genes.

Posted by: John Glennon at October 27th, 2005 1:28 PM
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