Re: 300 Pounds of Joy
[from a paper on the economics of obesity]
http://www.uni-kiel.de/ifw/konfer/newtech/loureironayga.pdf
There are mainly two arguments that could justify the growth of
overweight problems around the world: some researchers argue that
obesity growth is mainly due to a higher intake of calories, while
others state that obesity is mainly caused by a lower expenditure of
calories in daily activities. In line with the calorie consumption
argument, Cutler, Glaeser, and Shapiro stated that Americans have
become more obese over the past 25 years primarily due to the
consumption of more calories. Analyzing changes in food consumption
between the mid-1970s and the mid-1990s for male and females, they
showed that the growth in caloric consumption is enough to explain
the increase in weight. However, they pointed out that the main
reason for increased dietary caloric intake in the U.S. was calories
consumed outside of the main meals (i.e., snacks). They showed that
Americans nowadays eat more frequently than they used to, even though
average caloric consumption at dinnertime has been somewhat reduced.
Their results also suggested that obesity is not primarily the result
of more women working in the labor force.
Other recent obesity related studies by economists are those by
Philipson and Posner, Philipson, and Lakdawalla and Philipson. They
all concluded that increases in BMI over time are related to a lower
use of calories (due to reductions in the strenuousness of work).
Philipson and Posner presented a theoretical model that suggests that
technological change is a major factor that contributes to rising
obesity rates. Philipson also suggested other potential reasons that
could explain the growth of obesity rates. These reasons include,
among others, the change from rural to urban societies and changes in
cultural habits, such as a higher rate of passive entertainment.
Lakdawalla and Philipson, on the other hand, used data from the
National Health Interview Survey from 1976 to 1994, and from the
National Longitudinal Survey of Youth from the period 1982 through
1998. They empirically estimated the relationship between obesity and
reduction of physical activity and concluded that about 40 percent of
the total growth in obesity is due to expansion of the food supply,
potentially through agricultural innovation, and about 60 percent is
due to demand factors such as decline in physical activity in market
and home production.
Chou, Grossman and Saffer looked at the role played by other societal
forces that may alter the individual’s time allocation for food
preparation and consumption in an industrialized society. In
particular, their main hypothesis was that given the higher value of
time in industrialized societies, individuals would devote more time
to the labor market, thereby having less time available for food
preparation and leisure. Using cross sectional data from the
Behavioral Risk Factor Surveillance System (BRFSS), they analyzed,
among other factors, the role of the different restaurants, the price
of a meal in each type of restaurant, the price of food consumed at
home, the price of cigarettes, hours of work per week and hourly wage
rates by socio-demographic characteristics. Their main results
indicated a large positive effect associated with the per capita
number of restaurants. In addition, the authors found that downward
trends in food prices account for part of the upward trend in weight
related incidence, while increases in cigarette prices are associated
with growth in weight related problems.
[…]
Direct interpretation of the coefficients allows us to assess the
relative impact of each of the explanatory variables, ceteris
paribus. Based on the results obtained via GLS models with random
effects, an extra 100 calories in the daily calorie intake correspond
to an average growth of 0.6 percent in the number of individuals with
overweight problems and an average growth of 0.8 percent in the
number of obese individuals, ceteris paribus. Further, an increment
of 1 percent in female labor force participation rate increases the
number of overweight individuals by 0.52 percent, while female labor
participation is not a statistically significant factor contributing
to obesity. Mitigating factors such as expenditures in education and
contributions from consumers to the agricultural sector (via
agricultural prices) seem to have a higher impact on reducing
exclusively obesity problems than on reducing the incidence of
general overweight problems. A 1 percent increase in the percentage
of CSE [= consumer support estimate, a proxy for protectionist ag
subsidies] contributions decreases the percentage of individuals with
general weight problems (overweight and obese) by 0.06 percent and
the number of obese individuals by 0.12 percent. In terms of
expenditures in education, a 1 percent increase in GDP dedicated to
education decreases the incidence of obesity by 2.41 percent, while
it is not a statistically significant mitigating factor in the case
of general overweight problems. The importance of the effects of
change from rural to urban societies and the reduction of physical
activity on overweight and obesity rates are reflected by the
magnitudes of the parameter estimates of the variables denoting the
percentage of rural population and the number of kilometers driven by
cars. Specifically, a 1 percent increment of rural population
decreases the general overweight rate by 0.40 percent, while an
additional thousand of kilometers per capita driven by private cars
increases on average the obesity rate by
0.46 percent, ceteris paribus.