School professor takes on some weighty topics
Philipson argues that though obesity may be a medical problem,
it represents an efficient economic outcome.
former member of the Swedish national volleyball team,
Tomas Philipson knows something about fitness. And as a graduate
of the University of Pennsylvania's Ph.D. program in economics,
he can play the numbers game as well.
volleyball player Tomas Philipson blames
obesity on economoics not french fries.
Since 1998, he has combined these enthusiasms as
a professor in the Irving B. Harris Graduate School of Public
Policy Studies, scoring points by applying economics to health-related
topics, such as elderly care, AIDS, and life expectancy. "Like
most scholars," he says, "I want to work on topics that are important
and that haven't been studied--particularly when people don't
think they have anything to do with economics."
His latest example is a working paper, co-authored
by Law School senior lecturer Richard A. Posner, that links technological
advances to a worldwide rise in obesity. The paper--to be submitted
soon to a professional journal--grew out of the authors' surprise
that more had not been written on the economics of obesity, given
the condition's prevalence and costs. The World Health Organization
recently declared obesity an international "epidemic," common
in industrialized nations and on the rise in developing countries.
Meanwhile, the U.S. Department of Health and Human Services estimates
obesity cost the nation $99 billion in medical expenses and lost
productivity in 1995 alone.
In "The Long-Run Growth in Obesity as a Function
of Technological Change," published as a working paper by both
the Harris School and the National Bureau of Economic Research,
Philipson and Posner argue that economic incentives are behind
the poundage surge that has left 10 to 25 percent of adults in
Western countries medically overweight. They don't dispute that
the expansion of the world's waistlines stems from taking in more
calories than are burned through physical activity. But they do
hope their paper will help turn conversation about the upward
trend from its current emphasis on changes in how people eat to
a discussion of changes in how they work.
Obesity boils down to economics, Philipson says,
for three main reasons. First, economically spurred technological
advances in food production and distribution have made high-calorie,
fast-food diets possible. Second, those same advances have made
the overall economy increasingly more dependent on bytes than
brawn. Moreover, individuals get fat only after weighing the economic
costs and benefits of calorie consumption against their personal
preferences. "The price of taking in more calories has gone down
and the price of spending them has gone up," he explains. "To
get paid in the past you had to engage in manual labor. Now it's
the opposite. You have to pay with your time to exercise off the
To portray obesity in economic rather than health
terms, Philipson and Posner designed mathematical models to account
for the interplay of such factors as weight, diet, labor supply,
and off-the-job exercise. "Math allows you to be more precise
in your thinking and disciplines what you are thinking," Philipson
says. "Initially, it's my primary tool. You learn about a problem
by setting up a world where the problem exists and then seeing
what in that world will affect it. The key is understanding that
theoretical and empirical work are complementary."
In their mathematically modeled world, the researchers
found that the rise in obesity can be viewed as an efficient outcome
of economic and personal decisions. Generally speaking, Philipson
says, "people would rather take higher-paying jobs and be obese
than take lower-paying, more physical jobs and be thin. If people
could choose to be their medically recommended weight without
consequences, then they might want to be that. But it isn't without
consequences. It has an economic-opportunity cost."
However, note the researchers, individuals in technologically
advanced countries are not likely to balloon unchecked. Modeling
the relationship between income and weight, they show how obesity
tends to fall as income rises in rich countries and rise as income
rises in poor countries. When food prices are low, Philipson explains,
people spend a smaller share of their income on food and tend
to consume more calories, but only up to a certain point--at which
concerns for being above their ideal weight kick in. By contrast,
in poorer, less developed countries where food prices are high,
obesity becomes a physical symbol of wealth.
Considering obesity as self-limiting and as primarily
resulting from technology rather than health-related reasons,
such as increases in calorie consumption or declines in cigarette
smoking, Philipson and Posner conclude that government-funded
public education initiatives will not effectively ward off fat.
Take for example, Philipson says, the U.S. Department of Health
and Human Services' Healthy People 2010 campaign, which aims in
part to reduce obesity. Its Web site (www.health.gov/healthypeople)
warns that obesity substantially raises the risk of a host of
illnesses, including Type 2 diabetes, heart disease and stroke,
gallbladder disease, arthritis, and certain cancers, and recommends
that obese people significantly change their eating, shopping,
exercising, and social habits.
The problem, says Philipson, is that the right incentives
are not in place. "It doesn't take a rocket scientist to know
how to lose weight," he says. "Most people know there are adverse
consequences to being overweight. Knowing the exact details of
their risks probably won't change their behavior because they've
already taken the risks into account and accepted the tradeoffs
on an individual level." Instead, Philipson suggests, if the government
really wanted to influence people's weight, it would provide subsidies
for physical activity or tax calorie intake. "What will change
behavior," he says, "is a change in the incentives."
Philipson plans to continue studying how technology
has contributed to obesity. He'll be comparing how technological
advances have affected the weight of workers in different occupations
and trying to answer questions such as whether blue-collar workers
tend to put on pounds when they retire while white-collar workers
Although his research provides a different rush
than that of a professional volleyball player--a path Philipson
says he might have pursued were it not for a knee injury in his
early 20s--he has enjoyed the similarly competitive nature of
scholarship. "Academics come up with new ideas that help to better
explain facts," he notes, "so in a sense academics come up with
ideas that out-compete old ones."