A Gaining Trend: Obesity in the United States
After completing this continuing education article, the pharmacist should be able to:
- Describe weight gain trends in the United States since 1960 and their general effects on health.
- Calculate the body mass index and calories needed for weight loss or maintenance.
- List the strengths and limitations of low-carbohydrate and low-fat diets.
- Identify the 2 major weight-loss medications used in the United States.
- Explain how bariatric surgery contributes to weight loss.
Why are Americans gaining somuch weight? According tothe 1999-2000 NationalHealth and Nutrition Examination Survey,two thirds of adults in the UnitedStates were overweight and 30.5% wereobese.1 Whereas these numbers aloneare disturbing, the trend that they representis even more upsetting. From1960 to 2000, the incidence of overweightAmericans (body mass index[BMI] 25-29.9) rose from 31.5% to33.6%, while the incidence of obesity(BMI ≥30) more than doubled from13.3% to 30.9%.1 Even the incidence ofextreme obesity (BMI ≥40) increasedfrom 2.9% to 4.7% from 1988 to 2000.
Both sedentary lifestyles and dietarychanges have played an important rolein this startling trend. Less than onethird of Americans participate in regularphysical activity.1 Portion sizes in home,restaurant, and prepackaged meals andsnacks have increased, helping to pile onthe pounds, especially because most peopletend to eat the entire serving. Additionally,more people are eating outsidethe home than in previous years, a trendthat is associated with increased foodintake, body weight, and body fatness.2
Obesity in the United States is a majorhealth concern. Annual obesity-relatedhealth care costs range from $70 billionto $200 billion.3 Known complicationsof obesity include type 2 diabetes mellitus,hypertension, congestive heart failure,lipid disorders, arthritis, and certaintypes of cancers.3 Conditions associatedwith obesity include increased cholesterol,pregnancy complications, urinarystress incontinence, and psychologicaldisorders.1 These conditions lead toalarming results: 300,000 deaths peryear are associated with obesity, poordietary habits, or physical inactivity.1
Traditionally, obesity was assessedusing one number: the number thatappeared when a person stepped onthe scale (weight). Today, the determinationof obesity is a more refinedprocess, using BMI, waist circumference,and overall medical risk.4
BMI is a simple equation that assessestotal body fat more accurately thanbody weight alone. To determine BMI,a patient's weight in kilograms is dividedby the square of the patient's heightin meters: BMI = weight in kg/(height in meters)2
To calculate BMI in pounds andinches, the following formula is used:
BMI = (weight in pounds X703)/(height in inches)2
The classification of BMI values is listedin Table 1. A BMI of 18.5 to 24.9kg/m 2 is considered normal. Values>24.9 kg/m 2 are considered overweight.Values >30 kg/m 2 are considered obese.4
Although BMI is a fast, convenientway to assess obesity, it should be usedwith caution in certain patients, suchas those with edema, high muscularity,muscle wasting, and limited stature. Itsvalues may not be an accurate reflectionof body fatness.4 For example, avery muscular person may be classifiedas "overweight" when he or she isactually very fit. Conversely, a personwith low muscle mass may be classifiedas having "healthy weight" when he orshe has poor nutritional reserves. It isimportant to use the BMI equation as atool in the patient's assessment andnot as the entire assessment.1
Waist circumference is anotherimportant tool used in determiningobesity and potential obesity-relatedcomplications. Centrally locatedweight has been independently linkedwith health risks associated with obesity,such as cardiovascular disease, type2 diabetes mellitus, and hypertension.5This tool is especially useful in patientswho are normal or overweight, and itis insignificant in patients with a BMIof >35 kg/m 2. Women with a waist circumferenceof >35 inches and menwith a waist circumference of >40inches should be considered at risk forobesity-related complications.4
The pathophysiology of obesity isstill being researched. The adipocyte(fat cell) has been found to secretemany hormones that influence energymetabolism. When released from theadipocyte, leptin influences energyintake through receptors on the hypothalamus.Whereas levels of leptinhave been found to correlate with obesity,its role is still not completelyunderstood, and leptin treatment isnot likely to be effective in treatingobesity.2 The cause of obesity is not fullyunderstood and appears to resultfrom a combination of social, behavioral,cultural, physiologic, metabolic,and genetic factors.4
If the benefits of weight loss areobvious, why are so many Americansstill overweight? Even a minimalweight reduction of 5% to 10% inoverweight or obese individuals canreduce the risk of mortality and morbidity,6 a goal that can be achieved byreducing caloric intake by 500 to 1000calories per day.7 Unfortunately,weight loss—and especially weightmaintenance after weight loss—can bechallenging for even the most determinedindividuals. Weight loss requireslifestyle modification, oftenthrough dietary changes, exercise regimens,pharmacotherapy, or a combinationof all 3 approaches.
Fad diets promise and produce rapidweight loss, often with the illusion ofunrestricted calorie consumption.8 Forexample, many a dieter has tried theinfamous "Mayo Clinic Diet," a faddiet circulating for the past 30 yearsthat is not—and never has been—supportedby the Mayo Clinic. The diethas several versions and usually consistsof grapefruit consumption prior tomeals. Meals range from salad tobacon, depending on the variation ofthe diet. Despite its nutritional inconsistency,the selling point of the dietremains the elusive promise of weightloss with the false endorsement of theMayo Clinic.9 Weight loss associatedwith fad diets, however, is rarely sustainable,and the long-term healthimplications of fad diets are rarelystudied. In spite of their popularity, cliniciansshould caution patients awayfrom the use of fad diets.8
General health guidelines for weightloss suggest increasing activity, decreasingdietary fat, and decreasing dietarysugar.10 A 1-lb weight loss requires adietary deficit of 3500 calories. Reductionof calorie consumption by 500 to1000 calories per day can result in a 1- to2-lb weight loss per week, the amountgenerally recommended by health careprofessionals.4 Although conventionalweight-loss regimens have involved anenergy-deficient diet high in carbohydrateand low in fat, recent dietingtrends suggest the opposite: a low-carbohydratediet (<10% of daily caloriescoming from carbohydrates) and unrestrictedfats and proteins.
The Atkins diet, originally publishedin 1973 and republished in 1992 and2002, is a popular example of a low-carbohydratediet. The diet promotes10% of the total daily caloric intakefrom carbohydrates and ~40% fromfat. An average diet usually derives~30% of its calories from fat.11 Fourtimes as many dieters have read RobertAtkins' diet book as any other dietbook. Individuals likely to turn toAtkins' book are those shying awayfrom prescription treatment, havingminimal health care provider contact,and looking for a self-help solution toweight management.12
The Atkins Nutritional Approachpromotes a nutrient-rich diet consistingof unprocessed food and vitaminsupplementation, along with restrictionof processed or refined carbohydrates.Examples of restricted carbohydratesinclude high-sugar foods,breads, pasta, cereal, and starchy vegetables.The regimen consists of 4phases: Induction, Ongoing WeightLoss, Pre-Maintenance, and LifetimeMaintenance.13
During the Induction phase, whichis the first 14 days on the Atkins diet,carbohydrate intake is limited to <20g/day.12 These first 2 weeks are promotedto take the weight off quickly byinducing the body into ketosis, asstored fat is consumed for energy.13 Inthis phase, however, weight loss maybe partially due to diuresis, whichwould artificially inflate weight-lossresults.8
After 2 weeks, the Ongoing WeightLoss phase begins, at which point thedieter slowly adds carbohydrates backinto the diet at a rate slow enough tocontinue weight loss.13 Once the goalweight is achieved, total daily carbohydrateintake may be increased as appropriate.12
The Pre-Maintenance phase preparesthe dieter for long-term dietarychanges to maintain the weight loss byslowly adding carbohydrates to thediet at a rate of 10 g/week. The LifetimeMaintenance phase is an individualizedguideline for low-carbohydratedietary balance aimed at maintainingweight loss.13
A current and extremely populardiet is the South Beach Diet. This dietproclaims to be neither "low-carb norlow-fat" and advocates weight lossthrough restriction of "bad carbs" and"bad fats." Despite its proclamationsto the contrary, the South Beach Dietis similar to the Atkins diet in its 3-phase plan of carbohydrate restrictionand gradual reintroduction. The firstphase lasts for 2 weeks and consists ofa diet of meats, fish, shellfish, nuts,eggs, and cheese. Bread, rice, potatoes,pasta, fruit, and alcohol are notallowed during this phase. Duringphase 2, carbohydrates are slowlybrought back into the diet at a ratethat still allows weight loss. The finalphase focuses on dietary balance toensure weight maintenance.14
The pathophysiology of weight lossfrom carbohydrate restriction involvesthe body's mobilization of glycogenfrom the liver and the muscle, resultingin energy derived from gluconeogenesis.Dietary and endogenous fat are brokendown into ketone bodies, whichfunction as energy. When this processis combined with calorie restriction,weight loss occurs.8 Calorie restrictionprobably results from the monotonyand simplicity of the diet, increasedsatiety with high-fat and high-proteinfoods, and other factors affectingappetite.12 Low-carbohydrate diets aresaid to promote lipid oxidation, promotesatiety, and increase energyexpenditure.15 Additional weight lossafter the Induction phase, however, isbelieved to be due to calorie restriction,not changes in the body's metabolism.8
There are limits associated with thelow-carbohydrate diets. First, dietshigh in fat, especially saturated fat,have been linked with certain cancers,increased plasma lipids, insulin resistance,glucose intolerance, and obesity.Second, increased fat intake may beassociated with cardiovascular risksthat have not yet been studied. Third,long-term effects of ketosis have notbeen studied. Lastly, low-carbohydratediets are rarely studied for longer than6 months, so long-term cardiovascularand renal effects have not been established.15
Current evidence supports a dietconsisting of low saturated fat andhigh complex carbohydrates fromfruit, vegetables, and whole grains todecrease the risk of hypertension, cancers,coronary heart disease, andhypercholesterolemia.2 Fibers found incomplex carbohydrates help to lowercholesterol and insulin secretion.Avoidance of these foods may actuallyimpede dieting and health goals.8
In one of the longest studies availableof the Atkins diet, 63 subjectswere randomized to either a low-calorie,high-carbohydrate diet or theAtkins' low-carbohydrate, high-proteinand high-fat diet. The low-carbohydratedieters were given a copy ofDr. Atkins' New Diet Revolution and metwith a registered dietitian beforebeginning the study. The low-calorie,high-carbohydrate group participantsalso met with a registered dietitian priorto the study and were given copiesof The LEARN Program for Weight Management,which is consistent with theDepartment of Agriculture's FoodGuide Pyramid. Their diet consisted of~1200 to 1500 calories per day forwomen and ~1500 to 1800 calories perday for men, with 60% of daily caloriesfrom carbohydrates, 25% from fat,and 15% from protein.
At 3 months into the study, the low-carbohydrategroup had lost moreweight 6.8 ± 5.0 kg versus 2.7 ± 3.7 kgfor the low-calorie group. At the end of1 year, however, the difference inweight loss between the 2 groups wasno longer statistically significant.12
These findings are important in theirimplication for long-term weight-lossoutcomes associated with the low-carbohydratediet. Although carbohydraterestriction resulted in a fasterweight loss, the end result was eventuallythe same. The researchers determinedthat the weight loss was likelysecondary to calorie restriction, despiteunrestricted intake of fat and protein.This result suggests that macronutrientrestriction does not affect weight lossin a calorie-deficient diet.12
Another potential concern with low-carbohydratediets is the effect ofincreased dietary fat on the lipid profile.After 1 year, there was no significant differencein total cholesterol or low-density-lipoprotein (LDL) cholesterol betweenthe 2 groups. The low-carbohydrategroup, however, displayed agreater decrease in triglycerides and agreater increase in high-density lipoprotein(HDL) cholesterol.12
Low-carbohydrate diets have beenpromoted as improving insulin sensitivity.Complications of insulin resistanceinclude atherosclerotic processes,such as inflammation, decreased size ofLDL particles, and endothelial dysfunction.16 After 6 months, both groups hada significant increase in insulin sensitivity.There was no significant differencein insulin sensitivity after 1 year,suggesting that, in nondiabetic patients,macronutrient restriction doesnot affect insulin sensitivity.12
Despite these findings, the researchersstill feel that more long-termstudies are needed to determinewhether the benefits of the Atkins dietoutweigh the risks for coronary heartdisease in obese individuals. Interestingly,~40% of the participantsdropped out of the study: 43%dropped out of the high-carbohydratediet group and 39% dropped out ofthe low-carbohydrate diet group.12The high dropout rate in both groupsmay be due to difficulty adhering toany diet modifications.2
In other research, 53 obese femalesparticipated in a 6-month study tocompare weight loss and cardiovascularrisks from a low-fat diet recommendedby the American Heart Association,versus a low-carbohydratediet. The low-fat diet consisted of 54%of total daily calories from carbohydrate,18% from protein, and 28%from fat. The low-carbohydrate groupconsumed 15% of their total dailycalories from carbohydrates, 28% fromprotein, and 57% from fat.
After 3 months, the low-fat-dietgroup had lost 4.2 ± 0.8 kg, while thelow-carbohydrate group had lost 7.6 ±0.7 kg. After 6 months, the low-fatgroup had lost 3.9 ± 1.0 kg, and thelow-carbohydrate group had lost 8.5 ±1.0 kg. Seven participants in the low-fatgroup and 4 in the low-carbohydrategroup discontinued the study.Both groups had decreased total cholesterol,LDL, and triglycerides, alongwith increased HDL, suggesting thatthe low-carbohydrate diet was bothsafe and effective as a short-termweight-loss mechanism. The authorsof the study, however, acknowledgedthat studies longer than 6 months arenecessary to determine long-termeffects of carbohydrate restriction onweight loss and cardiovascular risk.15
Whereas the low-carbohydrate dietis popular now, dieting trends alsohave embraced its opposite: the low-fatdiet. Dietary fat has been believed tocontribute to obesity by being usedand stored more efficiently than carbohydratesand consumed in excess.2Individuals following a low-fat diet areencouraged to consume <10% of theirtotal daily caloric intake from fat.Dietitians and health experts promotehigh intake of fiber-rich complex carbohydrates,such as brown rice, fruits,vegetables, whole grains, and naturallegumes, because these foods increasesatiety and contain fewer calories.Fiber also slows the absorption of foodfrom the gastrointestinal tract, preventinga rapid rise in blood sugar,which in turn prevents an insulinresponse.11
As with all diets, misconceptionshave arisen with this diet. Many individualsadhering to a low-fat dietincorrectly believe that only fat caloriescause weight gain, leading to anoverindulgence of grains and starches.Increased caloric intake, no matterwhere the calories come from, canresult in weight gain 11 (Table 2; Sidebar:The Old-Fashioned Solution—Calorie Counting).
Other Dieting Trends
Other popular diets include a high-calciumdiet, especially from dairyproducts, to promote weight loss.Although calcium intake has obvioushealth benefits, its role in weight lossneeds further clinical investigation.2
Advocates of high-protein diets suggestthat increased protein correlateswith increased satiety and increasedthermic effect from food. Again, littleevidence exists to support this theory,and the effects of high protein intakeon renal function and calcium balanceare unknown but are worthy ofconcern.2 Whereas a definite link hasyet to be established, epidemiologicdata show a direct relationshipbetween worsening kidney functionand high protein consumption inwomen with preexisting renal insufficiency.Additionally, a tentative linkexists between high dietary proteinand microalbuminuria in individualswith diabetes and hypertension.17
Interestingly, a moderately increasedprotein diet has been found to prevent weight regain after significantweight loss. A total of 148 individuals who had successfully lost 5% to 10%of their body weight were randomized to consume 15% or 18% of their caloriesfrom protein. The authors hypothesized that weight regaincould be minimized by increasing protein consumption by 20% (from astandard dietary baseline of 15%-18%). After 3 months, the group consumingthe higher rate of protein regained 50% less weight than thelower-protein group.6
Weight loss can be simplified to a game of numbers: calories consumedmust be less than calories burned. Exercise and weight loss appear to havea direct dose-dependent relationship: as exercise increases, so does weightloss. Burning calories creates an energy deficit, which leads to weight reduction.In fact, even without calorie restriction, exercise can result inweight loss.5
Yet, how much exercise is needed? Unfortunately, there is no concreteanswer. It has been hypothesized that the first 6 to 7 miles of exercise a weekare necessary just to prevent weight gain. In 1995, the Centers for DiseaseControl and Prevention (CDC) and the American College of Sports Medicinerecommended 30 minutes of moderate-intensity physical activity on most,if not all, days of the week to prevent weight gain. The Institute of Medicineof the National Academies, however, recently increased that recommendationto 60 minutes a day.5 The CDC recommends an energy expenditure of~1000 calories per week, or 150 minutes per week of moderate-or-greater-intensityexercise.18
A randomized, multicenter study of202 overweight subjects comparedexercise in 2 groups: one group with anenergy expenditure of 1000 caloriesper week; the other group with anenergy expenditure of 2500 caloriesper week. After 6 months, the weightloss in the 2 groups was essentially thesame. After 18 months, however, thehigh-energy-expenditure group hadlost more weight—and kept the weightoff—compared with the lower-expendituregroup.18
Exercise is crucial in long-term maintenanceafter weight loss.5,7 Many clinicianssuggest walking as an initialexercise program, especially for theindividual dreading time on the treadmillat a local gym. Walking is a safeand accessible form of exercise thatmost people can fit into their schedule.Patients beginning to walk should beadvised to start with a modest routine,such as 10 minutes 3 days a week, andto slowly increase their time and durationtoward a goal of 30 to 45 minuteson most or all days.4 The use ofpedometers is a current trend making adramatic difference in exercise habits.Working out with a group or a friendhas been shown to increase compliance.A buddy system should be suggestedto individuals struggling withan exercise program.18
In addition to preventing weightregain, regular exercise has beenshown to decrease the risk of developingcardiovascular disease and type 2diabetes. The benefit is greater thanthat from weight loss alone.4
In 1999, Americans spent $321 millionon obesity medications. Althoughlifestyle changes, such as diet and exerciseplans, are considered first-linetherapy, certain patients may requiremore intensive treatment. Pharmacologicintervention is recommended inpatients with a BMI of ≥30 or inpatients with a BMI of ≥27 who alsohave obesity-related risk factors or diseasestates.4
Weight-loss medication historicallywas advocated as a short-term treatmentto induce behavior modification,thus resulting in weight loss. This technique,however, was rarely successful.In 1992, Weintraub et al7 released astudy supporting long-term pharmacotherapythat changed the role ofweight-loss medications. The studyfound that weight loss was maintainedfor up to 3 1/2 years for patients on continuousmedication. Although theagents in the study, fenfluramine andphentermine, are no longer availabledue to associated valvular heart disease,the results of the study revolutionizedweight-loss standards. Insteadof being perceived as a personal weakness,obesity gained status as a chronicdisease state, complete with medicationtreatment.7
Currently, the only prescriptionmedications approved by the FDA forlong-term weight loss are sibutramine(Meridia) and orlistat (Xenical).4
Sibutramine acts centrally to inhibitthe reuptake of serotonin and norepinephrine,resulting in the control offood intake by delaying meals or causingearlier satiety.19 It is approved foruse for up to 2 years and should beused with a reduced-calorie diet.20Sibutramine typically is given as 10to 15 mg daily. Patients unable to toleratethe 10-mg dose may be switched to 5 mg.
Potential side effects include insomnia,dry mouth, asthenia, and constipation.19 Approximately 5% of patientsusing sibutramine discontinue thedrug secondary to side effects.7 Becausesibutramine may cause a significantincrease in blood pressure, regularmonitoring is required.20 Patients witha history of coronary heart disease,congestive heart failure, cardiacarrhythmia, or stroke or patients whoare currently taking a monoamine oxidaseinhibitor or a selective serotoninreuptake inhibitor should not takesibutramine. Sibutramine is metabolizedby the CYP3A4 P450 enzyme system,and caution should be used withinhibitors of that system, such as ketoconazoleand erythromycin.20
Orlistat is effective in establishingweight loss and slowing weight regain7by inhibiting the absorption of dietaryfats in the lumen of the stomach andsmall intestine, thus resulting inreduced calorie intake and weight control.Orlistat is given as 120 mg 3 timesa day with each fat-containing mainmeal. Higher doses have not showngreater benefit. Patients using orlistatshould be advised to maintain a balanced,reduced-calorie diet withapproximately 30% of the total dailycalories from fat.21
Gastrointestinal symptoms—includingoily spotting, flatus with discharge,fecal urgency, fatty stool, oily evacuation,increased defecation, and fecalincontinence—have been the mostcommonly observed side effects. Theyusually last between 1 and 4 weeks ofbeginning therapy.21
Although orlistat may be a safe,effective tool for weight loss or maintenancein some patients, it is not appropriatefor everyone. Orlistat should notbe given to patients with chronic malabsorptionsyndrome or cholestasis.Because orlistat has been shown toreduce the absorption of certain fat-solublevitamins, patients taking orlistatalso should take a multivitamincontaining fat-soluble vitamins. Concurrentadministration of orlistat andcyclosporine has been shown to resultin decreased cyclosporine levels, andcoadministration, if unavoidable,should be carefully monitored.21
The mechanisms of sibutramine andorlistat differ significantly: one decreasesappetite, whereas the other preventsfat absorption. What are theirdifferences in terms of weight loss? Inone study comparing the efficacy ofsibutramine to that of orlistat, 150women were randomized into 3groups: one group taking sibutramine10 mg twice a day, another taking orlistat120 mg 3 times a day, and thethird taking metformin 850 mg twice aday. All 3 groups experienced a decreasein BMI, with the sibutraminegroup decreasing BMI the most(13.57% vs 9.06% for orlistat and9.90% for metformin).22 It is importantto note, however, that the sibutraminedose used in the study exceeded thatrecommended by the manufacturer.
Another study evaluated orlistat'seffect on additional weight loss inpatients who had been using sibutraminefor a year. In a randomized,double-blind study, 34 women whohad successfully lost 11.6% ± 9.2% oftheir body weight during a year ofsibutramine therapy were assigned toeither sibutramine plus orlistat or sibutramineplus placebo. After 16 weeks,neither group had a significant changein body weight, suggesting that combinationtherapy after moderate weightloss was no more effective than sibutraminetherapy alone.23
Whereas prescription medicationsare available and effective for the treatmentof obesity, many Americans willturn to OTC medications before consultinga doctor or dealing with highprescription costs. Among the mostpopular OTC therapies for weight controlhave been herbal supplementscontaining ephedrine alkaloids.24 Althoughephedrine is no longer availablefor sale in the United States, it isimportant for health care providers tobe aware of the prevalence ofephedrine and its potential dangers.
Ephedrine, an adrenergic agent, exertsboth appetite-suppressant and thermogeniceffects.7 Ephedrine alkaloids,known as ma huang or Chineseephedra, are found naturally inplants.25 Other names include desertherb, joint fir, popotillo, sea grape, oryellow horse.26
Ephedrine alkaloids are similar toamphetamines. Their major activeingredient strongly stimulates the heartand nervous system, resulting in increasedblood pressure and circulatorysystem stress.25 A recent review of availabledata on ephedrine showed that thesignificant risk of heart problems andstroke did not outweigh the benefit ofshort-term weight loss.25 A study of callsto poison control centers, however,reported a higher rate of calls inresponse to ephedra than to other herbalsupplements. Ephedra accounted for64% of all calls regarding adverse reactionsto commonly used herbs.26
Adverse effects associated with the use of ephedra include cardiovascular eventssuch as hypertension, stroke, myocardial infarction, and fatal arrhythmias.26 As aresult of ephedra's danger to consumers, the FDA banned the sale of dietary supplementscontaining ephedrine alkaloids as of April 12, 2004. Patients continuingto use ephedrine for weight control should be encouraged to stop 29(see Sidebar: OTC Weight-Loss Products—Worth the Risk?).
Although it is a drastic extreme and is not intended for all dieters, bariatricsurgery is a weight-loss option that is gaining popularity and that should beconsidered for appropriate patients. Its recent prevalence results from a combinationof public awareness, advanced technology, shorter hospitalstays, and quicker recovery times. The frequency of bariatric surgery morethan doubled in the span of 1 year—from 40,000 procedures in 2001 to86,000 in 2002.31 More than 100,000 patients are expected to undergobariatric surgery in 2004.32
Nationally accepted requirements for bariatric surgery include a BMI of≥40, a BMI of ≥35 with certain comorbidities—such as severe sleep apnea, hypertension, cardiomyopathy relatedto obesity, severe diabetes mellitus, or musculoskeletal or neurologic concerns—and a long-term history of obesity, multiple failed weight-lossattempts, and compliance with dietary and behavioral changes as recommendedby the medical team. Contraindications for bariatric surgeryinclude a history of an eating disorder or psychological instability.31 As aresult of weight loss, bariatric surgery often improves the patient's comorbidities,such as type 2 diabetes, hypertension, heart disease, gastroesophagealreflux disease, sleep disorders, arthritis or joint pain, and asthma.31
The most commonly used weightloss surgeries are vertical banded gastroplasty,which reduces gastric volume, and Roux-en-Y gastric bypass,which limits food intake and alters digestion.4,31 Bypass, a combinationrestrictive and malabsorptive procedure, is done more frequently in theUnited States, because it tends to result in longer weight maintenance.32Bypass procedures have produced weight loss for up to 14 years and up to68% of excess weight.33
Obesity is impacting more Americans now than ever before. Perhaps themost unsettling aspect is the rapidly increasing trend of obesity: Americanshave gained—and are gaining—more weight now than in previous years.Obesity needs to be perceived as a chronic disease with resulting comorbidities and complications.
Individuals ready to implement dietary changes should be encouragedand educated on healthy lifestyle changes. Providers interacting withdieters need to be aware that fad diets and diet supplements may be ineffectiveand even dangerous. For many, regimens such as a low-carbohydratediet provide an eating habit guideline and effective weight loss. When dietchanges alone will not produce weight loss, pharmacotherapy needs to beconsidered. Although still viewed as a last resort, bariatric surgery is becominga more commonplace option for patients who are unresponsive tolifestyle modification and pharmacotherapy to treat obesity and to preventits complications.
The Old-Fashioned Solution—Calorie Counting
Most people have no idea how many calories they consumedaily. An easy way to confirm this fact is to ask 10people who are carrying some excess weight. Most willavoid answering the question, and, if they do offer ananswer, their answer will most likely be on the low side.Dietitians recommend keeping a food diary for a week.They ask patients to log every morsel of food consumed ina diary that indicates when they eat and the total numberof calories they consume. Sometimes, they ask patients torecord triggers to eating, as well as periods of exercise. Atthe end of the week, they work with the patient to determinethe patient's unique problems. Then, they determinea reasonable number of target calories for weight loss, identifyhealthy choices, structure food intake and exercise programs,and ask the patient to maintain the food diary untilhe or she has established healthy habits.
Potential dieters can monitor themselves, using anynumber of readily available tools. This technique is thebasis for the Weight Watchers program that uses a pointsystem. Dieters must know their target weight and the maximumnumber of calories they are allowed to reduce theirweight. Some of the premises seem simple, but they areremarkably effective:
- Dietitians discourage skipping meals, especially breakfast,because severe hunger will prompt the dieter to overindulge
- Increasing dietary intake of fruits and vegetables to 5 to 7servings daily is essential and improves health in many ways
- Adequate fluid intake (64 oz daily) is advised, to maintain hydration and reduce hunger
- Balancing protein, fat, and carbohydrates also is advised
- As dieters lose weight, gradual calorie reduction will benecessary. Thus, a 63-in-tall woman aged 46 yearsweighing 170 lb needs ~2200 calories daily to maintainher weight. If she consumes ~1700 calories a day, shewill lose 1 lb a week. When she reaches 150 lb, she willneed ~2000 calories a day for maintenance and willneed to reduce her consumption to 1500 to continuelosing. Should she attain a target weight of 136 lb, shewill be able to consume 1950 calories daily and maintainthis weight. So, as people lose weight, they need toreduce intake gradually. (Stepping up her exercise froma moderate to a high level will allow this woman to eat300 extra calories.)
- A 6-ft-tall man aged 46 years who weighs 250 lb andexercises moderately needs 3300 calories to maintainhis weight. Should he reduce his intake and lose 25 lb,he will need 3100 calories to maintain his weight. If hereaches his target weight of 185 lb, he can consume2750 calories daily and maintain his weight. (Again,increasing exercise to a high level allows him to eatanother 300 calories daily and maintain his weight.)
Dieting this way is easier now that the FDA requires manufacturersto include nutritional information on productlabels. Some dieters are amazed when they realize howsmall a serving is. Alternatively, several Web sites list foodsand their calories and nutritional content. One such sitethat is very helpful is Calorie Chart at http://www.caloriecountercharts.com/chart1a.htm.
In addition, numerous sites offer free calorie calculators. "Free Weight Loss Tips," available at http://www.weighlosstipsfree.com/weight_loss_tips_calorie_calculator.htm, was usedto calculate the examples used above. Other calculators areavailable at www.dietitian.com/ibw/ibw.html or at a host of other sites.
OTC Weight-Loss Products—Worth the Risk?
The dieting world has become inundated with OTC products promisingrapid weight loss. Advertisements for weight-loss supplements bombard uson television, on the Internet, and in magazines. Unfortunately, the safetyand the efficacy of many of these products are questionable. Be preparedwhen a patient asks about an OTC weight-loss aid!
Examples of OTC diet aids with poorly established health and dieting benefits are as follows:
- Fiber tablets: These tablets are advocated to bind with fats, preventingtheir absorption and thereby decreasing calorie consumption.
- Liquid diet: For instance, the "Hollywood 48 Hour MiracleDiet" is promoted to result in up to a 10-lb weight loss in 48 hours.The dieter drinks nothing but water and the "miracle juice," supposedlyclearing the body of toxins and fat. Anecdotal side effectsinclude palpitations, diarrhea, and headache, with weight loss resultingfrom water loss.27
- Diuretics: Examples are caffeine and pamabrom. The resultingweight loss is due to water loss, not fat loss, providing false hopeand even the danger of dehydration to dieters.
- Apple cider vinegar tablets: These tablets are promoted to aid inweight loss, but minimal weightloss data are available, and safetyand efficacy have yet to be established.28
- Green tea extract: This product is promoted to increase energyexpenditure and fat oxidation, resulting in weight loss, but itssafety and efficacy are still undetermined.
- Grapefruit capsules: These capsules are administered twice a daywith meals, supposedly inducing the individual's metabolism toburn fat more quickly and more efficiently. Safety and efficacyhave not been established.29
- Starch/carbohydrate blockers or interceptors: These agents preventabsorption of carbohydrates, resulting in decreased caloric intake. Minimal supporting scientificdata exist, however.30
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Monica Holmberg, PharmD: Phoenix Indian Medical Center, Phoenix, Ariz
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(Based on the article starting on page 66.) Choose the 1 most correct answer.
1. According to recent data, what fractionof Americans participates in regularphysical activity?
- Less than one half
- Less than one third
- More than one half
- All Americans participate in regular exercise.
2. How many deaths per year are associatedwith obesity, poor dietaryhabits, or physical inactivity?
3. What is the body mass index (BMI) equation?
- weight in kg/(height in meters)2
- (weight in kg)2/(height in meters)
- weight in kg/height in meters
- (weight in kg)2/(height in meters)2
4. BMI should be used with caution with which type of patients?
- Patients with muscle wasting
- Patients using weight-loss pharmacotherapy
- Patients with pneumonia
- Patients who have successfully lost 10% of their body weight
5. A 1-lb weight loss requires a dietary deficit of how many calories?
6. Weight loss from carbohydrate restriction results from:
- The body's mobilization of glycogen from the liver and the muscle.
- Energy derived from gluconeogenesis.
- Caloric restriction.
- All of the above.
7. Short-term studies have shown low carbohydrates to increase total cholesterol,low-density lipoprotein cholesterol, and triglycerides while decreasinghigh-density lipoprotein cholesterol.
8. Limits associated with low-carbohydratediets include the following:
- Diets high in fat have been linked to certain cancers.
- Increased fat intake may be associated with cardiovascular risksthat have not yet been studied.
- Low-carbohydrate diets are rarely studied for longer than 6months, preventing the study of long-term cardiovascular and renal effects.
- All of the above
9. A common misconception with the low-fat diets is that:
- Diets low in saturated fat have cardiovascular benefits.
- Only fat calories cause weightgain, allowing unlimited intake of grains and starches.
- Fiber-rich complex carbohydrates increase satiety.
- Fiber prevents an insulin response by slowing food absorption.
10. Increased dietary intake of which macronutrient has been shown to preventweight regain after significant weight loss?
11. Weight loss occurs when fewer calories are consumed than are burned.
12. How much daily exercise does theInstitute of Medicine of the National Academies recommend?
- 30 minutes
- 60 minutes
- 90 minutes
- 120 minutes
13. In addition to preventing weight regain, regular exercise has beenshown to decrease the risk of developing cardiovascular disease and type 2 diabetes.
14. Sibutramine induces weight loss by:
- Inhibiting the reuptake of serotonin.
- Inhibiting the reuptake of norepinephrine.
- Causing meals to be delayed.
- All of the above.
15. Regarding sibutramine, which of the following is not true?
- Regular blood pressure monitoring is required.
- It is metabolized by the P450 CYP3A4 system.
- It is safe to use with monoamine oxidase inhibitors.
- Caution should be used in patients with a history of arrhythmias.
16. Orlistat induces weight loss by:
- Promoting early satiety.
- Inhibiting the absorption of dietary fats in the stomach and small intestine.
- Inhibiting the reuptake of serotonin.
- Inhibiting the reuptake of norepinephrine.
17. Which is not a common gastrointestinal side effect of orlistat?
- Fatty stool
- Flatus with discharge
- Fecal incontinence
18. Ephedrine is a safe, effective means of weight loss.
19. Nationally accepted requirements for bariatric surgery include which of the following?
- BMI of ≥40
- BMI of ≥35 with certain comorbidities
- BMI of ≥30 with certain comorbidities
- a and b
20. In addition to weight loss, patients undergoing bariatric surgery havedemonstrated an improvement in comorbidities, such as diabetes, hypertension,and heart disease.