Our waistlines are rapidly expanding. Today, more than 65 percent of the entire adult population in the United States is overweight, and more than 30 percent is obese. This is an increase of 40 percent over the past 30 years and close to 50 percent over the last two decades.

Our youth are not protected from this health problem. On the contrary, since the 1980s, the number of overweight children has nearly doubled, and the number of overweight adolescents has almost tripled. The impact of more people who are heavier and larger influences future health care needs and related costs (today estimated to be at least $117 billion annually), as well as the morbidity and mortality rates of many associated diseases.

Not so obvious, yet important, are expenditures for items such as wider wheelchairs and bigger hospital gurneys and scales. The effect of a heavier society also brings about changes to long-established standards, ranging from the need to change clothing sizes to the manufacturing of ordinary living room chairs that must accommodate heavier loads.

Many different explanations have been proposed to delineate the cause, or causes, of this emerging epidemic. As early as the 18th century, a Dutch physician named Malcolm Flemyng suggested that some individuals might have an inherent "inclination" for exhibiting excessive weight. Studies in the fields of genetics and behavioral and environmental sciences reveal some of the answers but cannot explain the entire picture.

In the majority of cases, the basic problem most probably is related to an imbalance between increased energy consumption and decreased energy expenditure. This is not only a result of super-sizing and increased consumption of sugar-containing soft drinks, but probably a combination of increased caloric intake along with a decreased need for physical activities required for daily living in our society, such as walking or bicycle riding.

Various measures are used to quantify body fat. The most common measure is body mass index, or BMI, which is defined as a person’s weight in kilograms divided by the square of his or her height in meters. This is not an exact measure, as BMI cannot distinguish between body fat and lean mass. Consequently, people with increased muscle mass may have elevated BMI without being overweight. By definition, a BMI of 25 or higher is considered overweight and a BMI of 30 or higher is considered obese.

Waist circumference correlates well with BMI and provides a better measure of abdominal adiposity. This is significant, as truncal obesity is an important component of many overweight-associated diseases and conditions. Federal guidelines suggest that men with a waist circumference of 40 inches or more and women with a waist circumference of 35 inches or more are at an increased risk of developing co-morbid conditions. This thinking may change as more data about risk for developing disease are elucidated. A recent study indicated that men with waists between 37.9 and 39.8 inches had a fivefold higher risk of developing diabetes mellitus compared with men whose waists were between 29 and 34 inches.

The same Malcolm Flemyng, in 1760, noted that "corpulency, when in an extraordinary degree, may be reckoned a disease, as it in some measure obstructs the free exercise of the animal functions, and has a tendency to shorten life by paving the way to dangerous distempers." Almost 250 years later, several comorbid diseases and conditions have been identified in people with excessive weight. The more common ones are diabetes mellitus, hypertension, heart disease and stroke. Others include asthma, cancer, complications of pregnancy, depression, gallstones and sleep apnea. According to studies of actual causes of death, excess body weight may be among the top seven leading causes of preventable deaths in the United States.

If the current trend of weight gains among our youth continues, for the first time in the past two centuries, our nation’s children will have a shorter life expectancy than their parents. This will hold true unless medical advances in the future will more effectively treat overweight-associated diseases. Among adults, a BMI between 18 and 24.9 is considered neither underweight nor overweight. Yet, the lowest death rate has been observed among men with a BMI between 23.3 and 24.9, and among women with a BMI ranging from 22.0 to 23.4. For the severely obese person, the excess weight may reduce life expectancy by five to 20 years.

If the current trend of weight gains among our youth continues, for the first time in the past two centuries, our nation’s children will have a shorter life expectancy than their parents.

Our patients already have shown a great ability to change when confronted with the dire alternatives to healthier lifestyles. This is evident when looking at the reduction in cholesterol levels and cigarette smoking achieved over the past two to three decades. There is no reason to believe a campaign to reduce our nation’s excess body weight would not be equally successful.

Although many dentists have successfully initiated treatment for smoking cessation, few oral care providers have ventured into nutrition risk assessment. Both of these undertakings traditionally have been viewed as being outside the scope of dental practice but today are taught within the dental curricula in many dental schools. A growing recognition of their importance has resulted in the implementation of these practices in many dental offices across the country.

Should dentists participate in a national weight awareness and control campaign? Should we help to monitor activities such as diet and sedentary lifestyles? Can we, with guidance, learn how to institute and monitor behavioral interventions? It would benefit all patients if dentists were included in the support network for people trying to lose weight.

Although some of the consequences of obesity will have an indirect effect on oral conditions—such as the development of diabetes mellitus with possible accompanying periodontal problems—this alone is not enough justification to get involved. There needs to exist a stronger motivation, such as a desire to have an impact on patients’ general health. Direct participation in changing this health problem will not be simple, but is this not a challenge we should consider?