This is an excerpt from Introduction to Physical Education, Fitness, and Sport-9th Edition by Daryl L. Siedentop & Hans van der Mars.
In 2001 David Satcher, then-Surgeon General of the United States, reported that levels of obesity among Americans had reached epidemic proportions (USDHHS, 2001). Since that time, the overweight and obesity numbers have only increased. All developed nations have experienced significant increases in overweight and obesity throughout the last four decades, but none has had the amount of increase that the United States has had. Fryar and colleagues (2018a) reported that as of 2016, more than two-thirds of all adults and one-third of all children in the United States were overweight, with nearly 30 percent of adults and 16 percent of children obese (see figure 1.1). Approximately 80 percent of overweight adolescents will become overweight adults (Herman et al., 2009).
In principle, overweight and obesity results from an imbalance between energy intake and energy expenditure (Levi et al., 2006). This imbalance develops over time when caloric intake through eating and drinking consistently exceeds energy expenditure through physical activity. Children and youths consume more energy-dense, processed, and mass-produced foods than they did 40 years ago, and they are less physically active than they were then. In terms of food consumption, the primary factors are higher caloric intake, more dietary fat, higher caloric density of foods, and larger portions. These factors are related to less in-home cooking; greater reliance on take-out food; more fast food meals; and overreliance on soft drinks, sport drinks, and fruit drinks that are high in calories and sugars. The Organization for Economic Cooperation and Development (OECD) reported that about 71 percent of adults and 43 percent of youth in the United States are either overweight or obese (OECD, 2019).
Children and youths also spend significant amounts of time engaged in activities on screens: playing video games, watching TV, and connecting to the Internet. Lack of indoor and outdoor neighborhood play spaces and programs limits physical activity opportunity and access, and in urban communities it might be unsafe for children and youths to be active outdoors during after-school and weekend hours.
Be mindful that decreased physical activity and increased calorie consumption are the result of multiple factors. A key factor affecting physical activity levels and consumption of food and drinks is what is typically referred to as the built environment. For example, the physical layout of urban and suburban communities is generally designed to foster driving rather than walking or cycling. The lack of safe bicycle paths and conveniences like online shopping and drive-through or pick-up options at many places of business are all suppressors of physical activity. Consumption of food and drink might also be encouraged by such built environment factors as the displays of foods and drinks in supermarkets and convenience stores, the number of fast food restaurants within close proximity of many high schools, and the low cost of high-calorie fast food.
Overweight and obesity levels are also influenced by regional, economic, educational, and ethnic and social factors (Trust for America’s Health, 2018). In terms of level of education, obesity levels among people with a college degree hovered at just under 28 percent, whereas for those without a college degree, just over 40 percent were considered obese (Ogden et al., 2017). We also see variance in obesity levels in different racial and ethnic groups: 42.5 percent among Latino Americans, 48.1 percent among African Americans, 34.5 percent among white Americans, and 11.7 percent among Asian Americans (Ogden et al., 2017).
Poverty level is also a key determinant of health. In 2019 a family of four with an annual income below $25,750 was considered to be living in poverty (USDHHS, 2019a). Among adults living just above the federal poverty level, 40.8 percent were overweight or obese, whereas 31.2 percent of those with incomes at or above 350 percent above the federal poverty level were considered obese.
Geography is yet another factor that influences population obesity levels. Consider the following sample evidence based on state-level adult weight status (CDC, 2019a).
- Colorado has the lowest level of adult obesity at 23.8 percent, while West Virginia was the highest at 39.7 percent.
- Eleven states reported at or above 35 percent of their populations as obese: Alabama, Arkansas, Indiana, Kansas, Louisiana, Michigan, Mississippi, Oklahoma, South Carolina, Tennessee, and West Virginia.
- Between 2012 and 2017, 31 of 50 states had statistically significant increases in adult obesity levels.
Overweight and obesity are related to a large number of health problems, including coronary heart disease, type 2 diabetes, cancer, high blood pressure, high total cholesterol, stroke, liver and gall bladder disease, sleep apnea, respiratory problems, osteoarthritis, and reproductive health complications. Consider the following facts about the relationship of obesity and overweight to select diseases and conditions (Healthy Food America, 2017a, 2017b; Levi et al., 2006; Murphy et al., 2018).
Type 2 Diabetes
- More than 80 percent of people with type 2 diabetes are overweight.
- More than 20 million adult Americans have diabetes.
- Another 54 million are prediabetic.
- From 2016 through 2017, diabetes was the seventh leading cause of death in the United States.
- Medical costs associated with diabetes in 2012 were $245 billion.
Heart Disease and Stroke
- People who are overweight are more likely to suffer from high blood pressure, high levels of blood fat, and high LDL cholesterol—all risk factors for heart disease and stroke.
- Heart disease is the leading cause of death in the United States, and stroke is the third leading cause.
- One in four Americans has some form of cardiovascular disease.
- Persons who are overweight have increased risk for several types of cancer.
- Approximately 20 percent of cancer in women and 15 percent of cancer in men is attributable to obesity.
- Cancer is the second leading cause of death in the United States.
Health Risks Earlier in Life
- Younger adults who are obese face greater health risks earlier in life. Women who are obese at age 30 are more likely to die at a younger age and are significantly more likely to develop cancer.
- Obesity in middle age might create higher risk for developing dementia later in life.
It is also clear that overweight and obesity can influence psychological, social, and emotional issues for children, youths, and adults.
Focus On: Body Mass Index
Estimating people’s weight status can be done in numerous ways. BMI is an inexpensive method for estimating the degree of underweight or overweight among children, youths, and adults. While BMI is easy to calculate, it does have its limitations and might not be accurate for some persons. BMI is estimated by measures of height and weight related to age, which allows for BMI percentiles to be calculated for each age group. Children and youths between the ages of 2 and 19 who have BMIs between the 5th and 85th percentiles are considered to be at normal weight. Those above the 85th percentile are deemed overweight, while those above the 95th percentile are considered obese. For adults 20 years and older, the formula for computing BMI is BMI = weight (lbs) / [height (in.)] 2 × 703. For adults, an optimal range for BMI is 18.5 to 25. A BMI lower than 18.5 is considered to be underweight, a BMI over 25 is considered overweight, a BMI over 30 is considered obese, and a BMI of 40 or more is considered severely obese. BMI is commonly used because of the availability of height and weight measures and is an estimate of levels of body fat. Its accuracy, especially among older youths and adults, can be distorted by factors such as fitness level, muscle mass, and bone structure.