CHAPTER 22 OBESITY
CHAPTER 22 OBESITY
Intro 。 Calorie deprivation(in moderation)can make you healthier Cuba after the collapse of the USSR The starvation experiment at the University of Minnesota during WWll Obesity is a growing problem in the US and worldwide Why?What is causing this epidemic? Is it a public health crisis? What government responses are appropriate? Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics Intro • Calorie deprivation (in moderation) can make you healthier • Cuba after the collapse of the USSR • The starvation experiment at the University of Minnesota during WWII • Obesity is a growing problem in the US and worldwide • Why? What is causing this epidemic? • Is it a public health crisis? • What government responses are appropriate?
THE WIDESPREAD RISE IN OBESITY Ch 22 Obesity
Ch 22 | Obesity THE WIDESPREAD RISE IN OBESITY
When is a person obese? Q:Is a man who weighs 180 pounds obese? A:That depends whether the person is five feet tall or seven. Clearly,some accountingmust be made for height in defining obesity. 。 The canonical way to do this is calculate the body mass index or BMI: Definition 22.1 Body Mass Index:BMI=- Weight in kilograms =4.9× Weight in pounds (Height in meters)2 (Height in feet)2 A person is considered clinically obese if his or her BMI is 30 or greater. Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics When is a person obese? • Q: Is a man who weighs 180 pounds obese? • A: That depends whether the person is five feet tall or seven. • Clearly, some accounting must be made for height in defining obesity. • The canonical way to do this is calculate the body mass index or BMI: • A person is considered clinically obese if his or her BMI is 30 or greater
Obesity rates are rising 。 Body weight in the U.S.has been rising in fits and starts for at least the past 150 years. The proportion of adult Americans who are obese has more than doubled between 1977 and 2006. Body weight has been increasing for decades in every developed country in the world. The heaviest countries are all in the Anglosphere. Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics Obesity rates are rising • Body weight in the U.S. has been rising in fits and starts for at least the past 150 years. • The proportion of adult Americans who are obese has more than doubled between 1977 and 2006. • Body weight has been increasing for decades in every developed country in the world. • The heaviest countries are all in the Anglosphere
WHAT EXPLAINS INCREASING OBESITY? Ch 22 Obesity
Ch 22 | Obesity WHAT EXPLAINS INCREASING OBESITY?
What explains increasing obesity? Theory 1:Genetics Evidence suggests that genetics plays a key role in determining body weight for both children and adults. While genetics may predispose some to being heavy,they cannot be the reason for the rise in body weight. Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics What explains increasing obesity? • Theory 1: Genetics • Evidence suggests that genetics plays a key role in determining body weight for both children and adults. • While genetics may predispose some to being heavy, they cannot be the reason for the rise in body weight
What explains increasing obesity? Theory 2:The food industry One popular theory for explaining obesity levels is that fast food restaurants and agricultural corporations push unhealthy,fattening foods and large serving sizes on an unwary populace. There is evidence that living close to fast food restaurants increases bodyweight,especially among children. But even if the popularity of fast food restaurants has contributed to rising obesity since World War ll, bodyweight has been increasing since at least the mid 19th- century. Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics What explains increasing obesity? • Theory 2: The food industry • One popular theory for explaining obesity levels is that fast food restaurants and agricultural corporations push unhealthy, fattening foods and large serving sizes on an unwary populace. • There is evidence that living close to fast food restaurants increases bodyweight, especially among children. • But even if the popularity of fast food restaurants has contributed to rising obesity since World War II, bodyweight has been increasing since at least the mid 19thcentury
What explains increasing obesity? .Theory 3:Food price trends Since WWIl,improvements in the technology of agriculture have made food production substantially cheaper and driven down its price. The law of demand says that a decline in the price of a normal good will be met with an increase in the quantity consumed of that good-and people have responded to these price decreases just as expected. While some have pointed to rising portion sizes at meals as a cause of rising body weight,those rising portions are themselves a consequence of falling food prices. Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics What explains increasing obesity? • Theory 3: Food price trends • Since WWII, improvements in the technology of agriculture have made food production substantially cheaper and driven down its price. • The law of demand says that a decline in the price of a normal good will be met with an increase in the quantity consumed of that good—and people have responded to these price decreases just as expected. • While some have pointed to rising portion sizes at meals as a cause of rising body weight, those rising portions are themselves a consequence of falling food prices
What explains increasing obesity? Theory 4:Changing lifestyles 。 Sedentary Jobs:The labor economy in the developed world, which previously consisted largely of agricultural jobs,has become dominated by service and manufacturing jobs, which require less physical activity. Heating and AC:Bodies expend energy to cope with hot and cold temperatures,so air conditioning and central heating may be contributing to fat staying on bodies rather than being burned off. Automobile use:The automobile is credited with dramatically reducing average daily walking exercise in developed countries. Bhattacharya,Hyde and Tu-HealthEconomics
Bhattacharya, Hyde and Tu – Health Economics What explains increasing obesity? • Theory 4: Changing lifestyles • Sedentary Jobs: The labor economy in the developed world, which previously consisted largely of agricultural jobs, has become dominated by service and manufacturing jobs, which require less physical activity. • Heating and AC: Bodies expend energy to cope with hot and cold temperatures, so air conditioning and central heating may be contributing to fat staying on bodies rather than being burned off. • Automobile use: The automobile is credited with dramatically reducing average daily walking exercise in developed countries