Rampant obesity: What you can do

Screening for obesity: two key measures 

BMI is the most commonly used screening test for obesity (Table 1). It is strongly correlated with adult body fat but does not take into account the weight of muscle versus fat. Other techniques are available to measure body fat, but they remain impractical for general clinical use.

Table 1. Classification of overweight and central adiposity

	Body-mass index	Overweight classification
	25–29.9	Overweight
	30–34.9	Class I obesity
	35–39.9	Class II obesity
	> 40	Class III obesity

	Waist circumference	At risk
		Men >40 inches
		Women >35 inches

Central adiposity also increases the risk for cardiovascular disease; it can be determined by measuring waist circumference. Men are considered at risk if their waist measurement is more than 40 inches; for women, the risk benchmark is 35 inches. Note, however, that waist circumference measurements may be inaccurate for individuals with a BMI greater than 35.

Key points 

■Only 42% of overweight adults in the United States have been advised to lose weight by their health care provider.

■The U.S. Preventive Services Task Force recommends screening all adult patients for obesity. Those identified as obese (BMI ≥ 30) should be referred for counseling and weight loss programs.

■High-intensity counseling on diet and exercise, combined with behavioral interventions to provide motivation, support, and skill development, can produce modest, sustained weight loss (3–5 kg for one year or more) in obese adults.

■Behavioral interventions help improve intermediate outcomes by enhancing glucose metabolism, improving lipid levels, and lowering blood pressure.

■Orlistat and sibutramine, both FDA-approved medications for weight loss, can produce 2.6 kg to 4.8 kg of weight loss that is sustained for at least two years.

■Surgical treatment of obesity can result in major weight loss (28–40 kg) sustained for one to five years.

■For overweight patients (BMI of 25–29.9), clinicians should encourage healthy eating and physically active lifestyles.

Calculating body-mass index 

What the task force recommends 

In 2003, the U.S. Preventive Services Task Force issued a series of recommendations on the screening and treatment of obesity in adults, based upon a rigorous review of the evidence from 1994 through 2003.10 The Task Force examined randomized clinical trials, systematic reviews, and observational studies on treatment efficacy and health outcomes. Three recommendations were issued:

The treatment of overweight and obesity clearly poses challenges for clinicians. The encouraging news is that three major types of interventions have some proven efficacy: high-intensity counseling and behavioral approaches, pharmacologic treatments, and surgical interventions.1

Counseling and behavioral approaches 

The most effective interventions combine counseling on diet and exercise with behavioral interventions that enable individuals to learn new skills. Counseling interventions involve approaches that promote changes in diet (decreased calories, smaller portion size, different mix of foods) and physical activity (walking, biking). Behavioral interventions include strategies that help individuals acquire skills (shopping, meal planning), gain motivation (goal setting, rewards), and create support systems (walking buddy) to enable them to change their diet and patterns of daily physical activity.

The evidence base on counseling and behavioral approaches was a large systematic review conducted by the National Institutes of Health that included 29 randomized controlled trials (RCTs) and 17 additional counseling RCTs involving primarily nonHispanic white women.1 The most effective interventions to produce weight loss in obese adults (fair to good evidence) involved highintensity counseling and behavioral interventions either in a group or 1-to-1 approach. Intensity was defined by the frequency of the intervention. Thus, as noted previously, a high-intensity intervention involved more than one session per month for at least three months.

There was limited evidence on the efficacy of less intensive interventions for obese adults or for any intensity intervention in overweight adults. Although the data are limited, the Task Force did conclude that high-intensity counseling is applicable to obese men, multi-ethnic men and women, and older adolescents. (Because the RCTs involved mostly non-Hispanic white women, the Task Force based its recommendation on that group but extrapolated it to other adults).

Pharmacologic treatments: orlistat and sibutramine 

Pharmacologic interventions reviewed by the Task Force produced modest (3–5 kg) weight loss.1, 10 Based upon a review of 18 RCTs, two drugs—orlistat (Xenical) and sibutramine (Meridia), both approved for weight loss by the FDA—can produce from 2.6 kg to 4.8 kg of weight loss that is sustained for at least two years.

There are no data beyond two years on the benefits or harms of these drugs. Both have frequent but usually not serious adverse effects. Side effects common with sibutramine (a dopamine, norepinephrine, and serotonin reuptake inhibitor) include increased blood pressure and heart rate, insomnia, and dry mouth. With orlistat, a gastrointestinal lipase inhibitor, side effects include flatulence, oily spotting, and fecal urgency. Most experts recommend using these drugs only in conjunction with counseling and behavioral interventions as part of a program of lifestyle modification.

Surgical interventions: bypass, banding and gastroplasty 

Surgical treatment of obesity can result in major weight loss (28–40 kg) sustained from one to five years.1, 10 Procedures include gastric bypass, vertical banded gastroplasty, and adjustable gastric banding. These treatments are limited to individuals with a BMI greater than 40 (Class III obesity) and to those with a BMI greater than 35 (Class II obesity) plus risk factors for obesity-related diseases such as diabetes, cardiovascular disease, and certain types of cancer.

Adverse effects associated with surgical treatments include wound infection, re-operation, vitamin B deficiency, diarrhea, and hemorrhage. The postoperative mortality rate for surgical interventions is 0.2%.

What we still don’t know 

Given the magnitude and the burden of suffering from overweight and obesity in the U.S., the modesty of evidence on effective treatments is alarming. There are many unanswered questions as to which interventions will work best:

What clinicians can do 

Given the epidemic of overweight and obesity and the staggering health costs of obesityassociated diseases, clinicians must attend to body weight in their practice population. Only 42% of obese adults have received advice to lose weight from their health care provider.12 Although primary care clinicians will most likely not deliver weight-loss interventions, they have a critical role in assessing weight, informing patients about health risks, and making referrals to an intensive weight-loss program. Clinicians can: