Facts and Figures on Overweight and Obesity
- In 1999-2000, 64 percent of U.S. adults were overweight, an increase from 56 percent when surveyed in 1988-1994; 30 percent of adults were obese, an increase from 23 percent in the earlier survey .
- Dramatic increases in the prevalence of overweight and obesity have occurred in children and adolescents of both sexes, with approximately 15.3 percent of children aged 6 to 11 years and 15.5 percent of adolescents aged 12 to 19 years considered to be overweight .
- Overweight and obesity are associated with increased morbidity and mortality. An estimated 300,000 deaths per year may be attributed to obesity, and overweight and obesity increase the risk for coronary heart disease, Type 2 diabetes, and certain cancers .
- The total economic cost of obesity in the U.S. is up to $117 billion per year, including more than $60 billion in avoidable medical costs, more than 5 percent of total annual health care expenditures .
- The prevalence of overweight and obesity varies by gender, age, socioeconomic status, and race and ethnicity. For example, although overweight has increased among all children, the prevalence of overweight and obesity is significantly higher among non-Hispanic black and Mexican-American adolescents than among non-Hispanic white teens (12-19 years old) . A majority of non-Hispanic black women over 40 are overweight or obese .
The nation is currently facing a major long-term public health crisis. In recent years, unprecedented numbers of Americans of all ages have become either overweight or obese (Figure 1). This trend toward overweight and obesity has accelerated during the past decade and is well documented by numerous scientific analyses (see Facts and Figures on Obesity). Unfortunately, this trend toward obesity shows no signs of abating. If it is not reversed, the gains in life expectancy and quality of life resulting from modern medicine’s advances on disease will erode, and more health-related costs will burden the nation. It is estimated that almost half of the annual costs of obesity reflects indirect costs, such as loss of productivity caused by absenteeism, disability, and premature death . Obesity and overweight are preventable conditions for most Americans. The increasing prevalence in obesity-related illnesses must be reversed.
Figure 1. Prevalence of Obesity by Age, 1999 - 2000
Source: NHANES Continuous, 1999-2000 (JAMA 2002; 288(14):1723-27)
Health care providers can play a vital role in helping patients with obesity. The US Preventive Service Task Force (USPSTF) recently recommended that clinicians screen for obesity on all adult patients using the Body Mass Index (BMI), calculated as weight in kilograms divided by height in meters squared. People with a BMI between 25 and 29.9 are considered overweight, and those with a BMI of more than 30 are considered obese. An online BMI calculator can be found at www.cdc.gov/nccdphp/dnpa/bmi/calc-bmi.htm. The USPSTF also recommended that clinicians offer obese patients intensive counseling and behavioral interventions to promote sustained weight loss or refer them to other clinicians for these services.
Poor diet and physical inactivity, resulting in an energy imbalance (an imbalance between the calories consumed and the calories expended), are two of the most important factors contributing to the increase in obesity. Other contributing factors include psychological considerations and motivations, education level, time constraints, and even cooking skills.
Changes in food intake and energy expenditure.
Substantial changes in food intake and physical activity have occurred over the last 20 years in the U.S. Changes in food intake are better documented than changes in physical activity, since they have been easier to measure in research studies. Some examples of changes in food consumption and purchasing include:
- Research has shown that when adolescents eat on their own and not with their families, they are less likely to eat healthy food, including fruits and vegetables .
- Soft drink consumption, which consists of both sodas and juice-based drinks, increased by over 60 percent between 1972 and 1992 , and accounts for over 10 percent of the average adolescent’s daily caloric intake . While such drinks can be enjoyed in moderation, for many they may substitute inappropriately for water, nonfat or low fat milk, and lower-calorie drinks.
- An increased variety of products are available in supermarkets .
- People are eating outside the home more than ever . The proportion of the food budget spent on food consumed outside the home has grown from approximately one third in the late 1970s to almost one half in the late 1990s, and over this same time period, portion sizes of foods consumed both outside and in the home have increased substantially [11, 12].
Although each of these shifts has been associated with an increase in food intake, none has clearly been linked to the onset of obesity. It is the imbalance between food intake and energy expended, however, that leads to weight gain. Calculations of the caloric content of fat suggest that an excess of 50 calories per day may produce as much as five pounds excess weight gain per year. (This is roughly the equivalent of one small cookie, per day.) Therefore, modest uncompensated changes in energy intake or expenditure over years may produce significant weight gains.
Behavior and weight management.
Many factors contribute to behaviors that lead to overeating, insufficient activity, and weight gain in contemporary American culture. There are intricate biological systems that regulate human hunger and satiety. It has been argued that humans are biologically programmed to prefer foods that are dense in fat, sugar and protein as a mechanism to assure adequate nutrition and healthy existence, particularly in times of scarce food. Additionally, human biology allows easy storage of nutrients in times of excess to provide a reserve for times of need. The biologic signals for satiety, or fullness, are often subtle, and are not perceived quickly or intensely. In ordinary circumstances, it is easy to eat more than is necessary to stop hunger anxiety signals. Eating food quickly furthers the likelihood of overshooting the satiety signal. The human predisposition toward conserving physical energy increases demand for inventions and technologies that help people increase productivity and reduce physical expenditure. For some individuals, exercising may run counter to the instinct to conserve physical energy.
The American social environment greatly facilitates the biologic and psychological predispositions toward eating, often contributing to repeated overeating. Social interactions and connectivity are important factors in interpersonal success and mental well-being. Food is a central component of many social gatherings. For most of the population, an abundance of food is readily available. Grocery stores and other kinds of stores offer increasingly large varieties of food, including heavily marketed and already prepared items. Many grocery stores even offer convenient home deliveries. As consumers eat more of their meals outside the home, restaurants play a bigger role in shaping ideas on appropriate portion sizes and balance of nutrients.