/publications/issue/2005/2005-05/2005-05-9541

Fighting the Battle Against Obesity

Author: Monica Holmberg, PharmD

Americans are gaining more weight now than ever. Obesity, defined as a body mass index (BMI) of =30, has more than doubled in incidence from 13.3% in 1966 to 30.9% in 2000, while the incidence of overweight Americans (BMI of 25 to 29.9) has grown from 31.5% to 33.6%. When obesity and overweight are combined, more than two thirds of Americans are overweight or obese.1

Along with tipping the scale, Americans'gaining trend has had an overwhelming impact on health care costs. Obesity-related costs range from $70 billion to $200 billion each year. Complications of obesity include type 2 diabetes mellitus, hypertension, congestive heart failure, lipid disorders, and arthritis.2 Yet, the cost of obesity surpasses mere money. Increased BMI is associated with higher mortality rates from cardiovascular events, diabetes, hypertension, gallbladder disease, sleep apnea, musculoskeletal disease, and gallbladder, endometrial, breast, and colon cancers.3

If obesity threatens health and well-being in such an alarming way, why are people still gaining weight, and how can pharmacists influence this dangerous health trend? Pharmacists can help patients identify obesity and its health risks. They can assist in implementing appropriate dietary changes and initiating exercise programs. When appropriate, pharmacists can counsel patients on both OTC and prescription drug treatments. Frequent interactions with at-risk patients allow pharmacists multiple opportunities to fight the battle against obesity.

Pathophysiology

What causes people to be overweight? Although social, behavioral, cultural, physiologic, metabolic, and genetic factors all influence individual body weight, the pathophysiology of obesity is only partially understood.4 The adipocyte has been found to secrete many hormones that influence metabolism. Leptin, when released from the adipocyte, influences energy intake through hypothalamus receptors. Although leptin levels correlate with obesity, the role of leptin is still not completely understood, and it is unlikely that leptin treatment will be effective in obesity therapy. Additional research is warranted to elucidate the cause of obesity and to determine a cure.5

Defining Obesity

Historically, one number assessed obesity: body weight as measured on a scale. Today, obesity is determined through methods that assess body composition more accurately, such as BMI, waist circumference, and overall medical risk.4

BMI is defined as a patient's weight in kilograms divided by the square of his or her height in meters:

BMI = weight in kg/(height in meters)2

It also can be calculated using pounds:

BMI = (weight in pounds X 703)/(height in inches)2

The classifications of BMI values are listed in Table 1.4

Body-weight distribution is another useful assessment tool. A waist circumference of >35 inches in women or >40 inches in men has been linked to obesity- related health risks, such as hypertension, cardiovascular disease, and type 2 diabetes mellitus.4,6 Although it is a useful tool in normal or overweight people, waist circumference is not significant in people with a BMI of >35.4

Weight Loss

To lose weight, one's daily caloric intake must be less than caloric expenditure. In other words, one must either eat less or exercise more.

Exercise

Exercise is an excellent catalyst for weight loss. Burning calories results in a caloric deficit, thereby leading to weight loss. Exercise and weight loss share a direct relationship: as exercise increases, so does weight loss.6 Recent data show that <1/3 of Americans participate in regular physical activity,1 even though recent recommendations from the Institute of Medicine of the National Academies suggest an exercise regimen of 60 minutes a day.6 Additionally, the Centers for Disease Control and Prevention recommends an energy expenditure of 1000 calories per week, or 150 minutes per week of moderate?or greater?intensity exercise.7

Yet, how can exercise be incorporated into the hectic American lifestyle? Walking is safe and accessible and usually can be fit into even the busiest person's schedule. New walkers should be advised to make a moderate start, such as 10 minutes of walking 3 days a week. As their stamina increases, walkers can increase their walking to 30 to 45 minutes on most or all days.4 Studies have shown that exercising with a friend or a group increases compliance. A partner or a buddy system is a good recommendation for individuals looking to begin a routine.

Diets

A 1-pound weight loss requires a deficit of 3500 calories, and diets simply provide guidelines for limiting caloric consumption. Most health care professionals recommend a 1-to 2- pound weight loss per week, which can be achieved by a daily caloric reduction of ~500 to 1000 calories.4

General guidelines for healthy eating habits include decreasing dietary sugar and fat.8 Popular dietary trends include a low-carbohydrate diet, a low-fat diet, and a high-protein diet (Table 2).5,9-11 When counseling patients, pharmacists should stress the importance of moderation. Reducing both dietary fat and carbohydrate will result in weight loss while maintaining a more well-rounded diet.3 Advise patients to limit portion size, read nutritional labels, and be patient yet persistent in their dietary modifications. Also, remind patients that weight gain results from excess caloric intake, no matter where the calories come from.8

Many a dieter has been enticed by a diet offering weight loss despite unrestricted calorie consumption?in other words, a fad diet. Fad diets, ranging from the grapefruit diet to the cabbage soup diet, offer a mirage of fast and easy weight loss. Whereas fad diets often yield their promised weight loss, their long-term implications rarely are studied, and their dietary regimen usually is not sustainable. Weight generally returns quickly. Despite the promised weight loss and the popularity of these diets, patients should be discouraged from fad diets.11

Drugs

In the appropriate patient, medication therapy provides an alternative means to weight loss. Two agents are approved for long-term weight loss in the United States: sibutramine (Meridia) and orlistat (Xenical).4 Although the drugs have completely different mechanisms of action, both essentially limit caloric intake so as to result in weight loss.

Sibutramine is a centrally acting reuptake inhibitor of serotonin and norepinephrine. It controls food intake by delaying the onset of meals or causing earlier satiety.12 It is dosed at 10 to 15 mg daily; patients intolerant of the 10-mg dose may be lowered to 5 mg. Patients should know that sibutramine is approved for use for up to 2 years and should be used with a reduced-calorie diet.13 Its side effects include insomnia, dry mouth, asthenia, and constipation12 and cause ~5% of patients to discontinue treatment.14

Sibutramine also may cause a significant increase in blood pressure and/or heart rate. Regular monitoring of both is required, and the use of sibutramine should be avoided in patients with uncontrolled hypertension. Additionally, patients with a history of stroke, arrhythmias, coronary artery disease, or congestive heart failure or patients who are currently taking a monoamine oxidase inhibitor should not take sibutramine.13

Orlistat inhibits dietary fat absorption in the stomach and small intestine. It is given 3 times a day with each fat-containing meal. Patients should be counseled to maintain a reduced-calorie diet with ~30% of the total daily calories from fat. Side effects include oily spotting, flatus with discharge, fatty stool, oily evacuation, increased defecation, and fecal incontinence. Tolerance of side effects usually develops within 1 to 4 weeks of initiating therapy.15

The opportunities are endless for pharmacist intervention in promoting weight loss and preventing the comorbidities associated with obesity. Diets, exercise, and medications can all play an important role in establishing and maintaining weight loss in the overweight individual.

Dr. Holmberg is a pharmacist with Phoenix Children's Hospital, Phoenix, Ariz.

For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. A. Stahl, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: astahl@ascendmedia.com.