Friday, January 15, 2010

Chewing (out) the fat

I've been making bits of this argument for years and maybe I should put it together. Here goes:

1. It is rational to trade off longevity for other kinds of benefits. Actually, it is not only rational, but commonly done. As Gary Becker says, most deaths are suicides: if one's overriding objective in life were to live as long as possible, one would live quite differently from the way people actually do.

2. Different people will presumably want to make their longevity-happiness tradeoff in different ways; there are no objectively right or wrong ways to do this; in the absence of externalities and other compelling reasons, the state should let them make such tradeoffs for themselves.

3. In a society with universal healthcare (e.g., Britain) it is sometimes claimed that fat people are a burden on the healthcare system. This isn't actually true. Fat people cost more per year of life, but less overall. (e.g. This study shows that the lifetime medical expenses of the obese/smokers are less than those of "fit" people.) Remember, the life expectancy even for obese people is somewhat higher than the retirement age. Therefore, healthy people generally spend their additional years of life as parasites rather than as generators of wealth. [In a society like the US the situation is unjust to the fat. Obese people, smokers, and others who are less likely to live past 65 are subsidizing the medical expenses of those who live past 65. There seems to be no compelling economic reason to provide this kind of incentive for living past 65.]

4. Life expectancy is not a sound measure of welfare any more than GDP per head. As Krugman argues here, the French put up with earning less because they get to take longer vacations. Similarly, obese alcoholics might be fine with heart attacks because they get to drink bacon martinis while they are alive. These are both, in principle, rational tradeoffs, though in both cases you can imagine conditions (acquiring expensive new obligations, being on your deathbed) where people regret their rationally made choices.

5. Exceptions should, I suppose, be made for the case of serious physical addiction, in which the addict seriously wants to change his lifestyle but can't. For long-time smokers I imagine this is a substantial fraction of the relevant demographic, but for drinkers, stoners, compulsive eaters, and non-exercisers it's a relatively small segment. e.g. there's a large grey area between drinking enough to increase your chances of liver cancer and drinking enough to be unable to go without booze; this is presumably where most regular drinkers fall.

6. Unlike smoking or public drunkenness, obesity does not obviously hurt other people. (Except on airplanes. I don't really have a problem with charging people extra if they don't fit in their seats.)

7. Arguably being obese increases your chances of being unemployed and therefore on public assistance. (And maybe it increases your chances of being poor and hence a beneficiary of progressive tax credits and/or welfare policies.) I'm pretty sure, however, that the causation goes the other way, and that whatever residual effect there might be is largely explained by anti-fat discrimination. If one could establish that being fat or a smoker made you sufficiently unproductive per hour that you were on the whole a ward of the state in times of full employment I would probably change my mind on this entire issue.


So to sum up etc. (1) I don't see that society has a compelling reason to want people to make the health/pleasure tradeoff in a way that's maximally skewed toward health. (2) One could argue that by feeding kids healthy food when they're young you avoid the tradeoff altogether because they learn to enjoy the mashed yeast. I am deeply skeptical of this: in general, food can be arbitrarily healthy and arbitrarily good for you only to the extent that the ingredients are arbitrarily upscale. This is unworkable for a large number of people. (The usual ways of dealing with lousy ingredients, e.g. spicing the hell out of everything a la Indian food, come with health costs.)

I should note that the basic reason I care about this issue is that I think Megan McArdle's right that there's something very Victorian and moralistic about the (blue-state) public's attitude to fat. I find this sort of hardworking/lazy dichotomy extremely irritating esp. since the "upright" classes tend to be smug, rich, and liberal.


Jeremy said...

The ability to delay gratification is a generally positive ability.

Westcott said...

"Life expectancy is not a sound measure of welfare any more than GDP per head."

Maybe not at the margin but on absolute scales I think it matters (getting developing nations up to our level). The kind of trade-off you're talking about only matters if you already have a good healthcare system such that people can basically live up to 70-80 without doing much.

Zed said...

Jeremy: says who?

Dice: I agree that my post only applies to developed countries but that's precisely where obesity is considered a problem.

Grobstein said...

This argument relies on assuming equal lifetime "production" for the obese and the non-obese. (That's what your retirement age observation in 3 does.) This could go wrong in a couple ways:

1. Life extension is health extension. If people who live longer because of healthy lifestyles are also healthy and able longer, they may work longer. Not sure how strong this is, as there are both income and wealth effects.

2. The same people who forbear present fat for future health probably have the set of forbearance skills that makes them more economically productive on average. It's not clear this matters, but it might.

The other line of attack is the rationality assumption, which many people (e.g. you in other contexts) would regard as crazy.

As a sidenote, we live in a society with a positive discount rate. Doesn't this suggest that late-life health expenditures matter less than early-life ones? I don't think this was accounted for in the study.

Zed said...

Re life extension: if the retirement age were 75 that might be true. 3. strongly relies on the fact that by and large people are retired well before they die, which is true in most of the developed world. I also don't really believe your premise. I suspect that being fat increases the overall odds of your dying of something quick rather than something slow.

Re fat-people-make-less: that's what I was trying to get at in 7. I believe the causal sequence is that poor people tend to get obese rather than that obese people tend to get poor. It's _possible_ that the kind of person that gets fat is also the kind of person who can't keep a job, but to the extent this is so I think it has to do with "character" (i.e., obesity is the sign of a slacker). This seems implausible as obesity rates rise and fall much faster than "character" can change. Also, trying to make slackers non-obese probably won't make them non-slackers so the incentives are unjustified.

Re discounting: I don't think that's the right end to think of it. From the POV of the state, a certain number of doctors and beds have to be provided for a certain number of sick people; this doesn't depend on whether they're 80 year old people born in 1930 or 50 year old people born in 1960.

I should have explained what I was trying to do with the rationality assumption. I was trying to invoke a meta-principle to the effect that it is bad to use the nanny state to prevent people from making socially harmless choices they _could_ have made rationally, even if it's hard to prove that any particular individual _did_ make the choice rationally. (The usual caveats apply: childhood experiences matter, no one is rational at three, etc.)

All of this is ultimately related to the question of whether universal healthcare programs give the govt a compelling interest in messing with your lifestyle. If the answer is yes then one's forced either to turn libertarian and oppose healthcare or accept govt. interference in one's decisions about drug and hamburger use. I think that the answer is basically no so the dilemma doesn't arise. (Wishful thinking? Conceivably.)

In a thoroughgoing libertarian system where healthcare is run by unregulated private insurers, the real question is whether one is willing to treat the old like one treats the fat.

zbs said...

I agree but defer on the grounds that there is a social value in less obese people to look at, and also a larger set of smaller people with whom to have sex.

Zed said...

Ah, but the deeper the cushion the sweeter the pushin', or however that line goes.

Jeremy said...

In my mind, the ability to delay gratification is a crucial part of implementing rational behavior. Assume you are able to estimate the present value of some future event. Given the choice to consume something now with the present value of X or something in the future with a present value of 2x, you must be able to delay gratification to reap the rewards of the future event. I would assert that in most cases acting rationally is a positive ability. Accuracy in the discounting procedure is another issue.

Zed said...

Three objections, from narrow to broad:

1. The business with the discount rate isn't tractable in a meaningful way. There isn't an a-priori-good way to estimate the likelihood of changes in taste, medicine and technology, etc. that would give you anything like a decent sense of how much you stand to gain or lose by delaying gratification. Sure, you'll find out in hindsight whether you chose wisely or not, but having a choice turn out well isn't evidence for its being rational.

2. Consider a simple model in which one's utility depends only (and linearly) on the number of hamburgers consumed. One's lifetime depends nonlinearly on this variable (you die in the end regardless. Also it gets harder to eat hamburgers as you age). The "optimal" lifetime, assuming that you're trying to maximize total utility, could be fairly low.

3. In any case I don't think total utility is the only "rational" function to maximize. There are paradoxes (like the so-called Lifespan Dilemma, see and refs therein) that would seem to suggest one ought to maximize something somewhere between total utility and average utility. In which case, obviously, the more you weight average utility the likelier you are not to delay gratification.

There's a common implicit association between "rationality" and certain kinds of behavior like saving, planning, and generally leading dull bourgeois lives. I would suggest that this is largely a function of class bias.

Jeremy said...

I am equating the ability to delay gratification with will power. I think it is important for people have the will power to implement their decisions even when they are difficult. Mine is not an argument about how you make decisions, it is an argument on how you execute them.