- Email: [email protected]
Weight Loss in Women
, , , , , ,
GYNAECOLOGY
WEIGHT
, , , , ,
Loss IN WOMEN
David Kincade, MD, FRCPC, 1 Carl Laird Birmingham, MD, MHSc, FRCPC, ABIM, FACP,2 1Fellow,
Division of General Internal Medicine, University of British Columbia, 2Professor and Head, Division of General Internal Medicine, University of British Columbia, Head, Division of Internal Medicine, Co~Director, Eating Disorders Clinic, St. Paul's Hospital, Vancouver, British Columbia
ABSTRACT
Obesity afflicts many women. In addition to the associated social stigma, obesity contributes to a variety of serious comarbidities and, independently, to mortality. Rational management of obesity requires a thorough assessment far causes and complications and a personalized weight management programme, with the appreciation that this is a chronic disease. As with any chronic condition, long-term foUow-up is required, and there must be a willingness on the part of the doctor and the patient to modify the plan accarding to results and goals. RESUME
Lobesiti afflige beaucoup de femmes. En plus du sentiment de gene qu'elle suscite sur Ie plan social, l'obesiti entraine des comarbidites graves et meme, par elle-meme, Ia mart. Une gestion rationnelle de l'obesiti exige une evaluation approfondie des causes et des complications et un programme de gestion du poids personnalise. II faut comprendre qu'il s'agit ici d'une maladie chronique. Comme pour toute condition chronique, un suivi it long terme est essentiel et Ie medecin et Ia patiente doivent rtre prets it modifier leurs plans selon les resultats et les objectifs.
KEY WORDS Obesity, women. Received on September 29th, 1998. Revised and accepted on November 5th, 1998.
JOURNAL SOGe
434
MAY 1999
,,, INTRODUCTION
Is
OBESITY DUE TO GLUTTONY OR LACK OF
WILLPOWER?
Obesity is defined as an excess of body fat. This excess is usually accepted as being more than 20 percent above the ideal body weight as defined by life insurance tables, or a body mass index greater than the eighty-fifth percentile. Obese patients may present to their physicians with the complaint of excess weight, an eating disorder, or with such a comorbidity as diabetes or hypertension. Morbid obesity is defined as a body fat 100 percent, or more, of normal. This term was coined in the 1950s to help to identify a group of patients whose risk from obesity is so great that obesity surgery may be indicated. Between one-quarter to one-third of adult North American women are overweight. In certain ethnic populations, this figure is substantially higher. 1 Despite the massive effort and billions of dollars spent in Canada and the United States trying to control weight, the prevalence of obesity is increasing among adults. 1,2 TRUTHS AND MYTHS ABOUT OBESITY
Although fat cannot be gained without the ingestion of more calories than are expended, obesity is usually due to a modest degree of overnutrition in someone who is genetically predisposed to gain fat. Many obese people gain at the rate of 10 pounds a year which, if multiplied by 3,500 kilocalories for every pound of fat and divided by 365 days, means that they are ingesting about 100 excess kilocalories a day (equivalent to an apple or one piece of bread). Humans have a "set point" for weight located in the hypothalamus that regulates many functions, including appetite and energy expenditure-which means that the obese are working against homeostatic mechanisms when they are dieting. For example, during dieting the body reduces resting energy expenditure by about a third, thus promoting return of the lost weight. 7 Some evidence suggests that these feedback mechanisms may be mediated in part by leptin (leptin receptors are located in the hypothalamus). 8 Therefore, obesity should be considered a chronic disease.
LIFESPAN AND OBESITY
ASSESSMENT OF THE OBESE PATIENT
In addition to contributing to a variety of conditions including hypertension, dyslipidaemia, diabetes mellitus and some cancers, obesity is independently associated with an increased mortality when compared to non-obese controls. 3-5 For example, a woman between 25 and 35 years of age who is 100 pounds over her ideal weight is 12 times as likely to die as a woman of ideal body weight.
CLINICAL HISTORY
A complete history of the obese patient is necessary to establish potential causes, confounders and complications. It is important to understand the pattern of weight gain in the patient over time in order to predict the expected course of weight change in the years to come. It is useful to learn what an individual weighed at certain stages in life and then to use these weights as standards for comparison. It is important to establish if there is any past history or current symptomatology of an eating disorder. Anorexia, bulimia and binge eating disorder all greatly complicate management. 9,10 A search for symptoms of hypothyroidism (lethargy, dry skin, cold intolerance, menometrorrhagia) or hypercortisolism (central weight gain, easy bruiSing, purplish abdominal striae, moon facies, buttock wasting) may prove helpful when considering secondary causes. Medications including estrogens, steroids and psychiatric medications may cause weight gain. Their use should be noted. A thorough review of systems may
WEIGHT CYCLING
There is a misconception in the lay (and medical) literature that weight cycling, or so-called "yo-yo dieting," leads to permanent detrimental physiological and psychological changes in the obese person. A thorough evaluation of available evidence failed to corroborate permanent changes in metabolism, deleterious effects on psychological profiles or in overall morbidity and mortality in patients who weight cycle. 6 Because of the negative consequences of obesity, we should continue to encourage weight loss, despite the inability of a substantial number of people to maintain it.
JOURNAL SOGC
435
MAY 1999
,,, presence or absence of medical complications. All obese patients exist on a spectrum ranging from low health risk (BMI <30 and an absence of medical complications) to extremely high health risk (BMI 35-40 with complications or BMI >40 even in the absence of complications). 11 It is of the utmost importance to place individuals within this spectrum in order to design an appropriate weight management plan.
reveal a variety of complications attributable to obesity (hypertension, diabetes mellitus, coronary artery disease, sleep apnoea, dyslipidaemia, arthritis, gallstones). The patient's functional capacity and the degree of debility associated with the obesity should be established. PHYSICAL EXAMINATION
The physical examination is focused initially on the documentation and quantification of obesity. In addition to measuring the weight and height, the body mass index (BMI) and the waist to hip ratio (WHR) can be quantified. The BMI is calculated by dividing the height in metres by the square of the weight in kilograms. A normal BMI is between 21 and 27, and overweight is defined as a BMI greater than 27.11 The waist to hip ratio is a simple tool for assessing fat distribution. Ratios of> 1.0 in men and >0.8 in women signify "apple" or android obesity which correlates with a risk to health beyond that suggested by weight alone. 11 Simple waist circumference has predictive value, and a measurement of >40 inches in a male or >35 inches in a female is considered a marker of increased risk. 12 The remainder of the examination is a search for corroborating physical evidence to support a potential secondary cause of obesity and signs of any medical complications.
SETTING GOALS
The most important factor before embarking on a longitudinal, often complex, weight management strategy is to assess patient readiness. Without complete patient involvement, even the best intentioned plans are doomed to fail. Once the patient has demonstrated willingness to proceed, it is important to set realistic, attainable and sustainable goals for weight. For most patients, especially those with a BMI >30, a target BMI two below their current one is both realistic and practical. A weight loss of this magnitude leads to improvement in comorbid conditions, albeit in the absence of a clear improvement in longevity. 13 DIET
It is necessary to establish an energy deficit in order to generate weight loss. A reasonable goal is to aim for a deficit of about 500 kcal per day, which is generally sustainable and palatable to the patient. Moderate deficit diets can be prescribed to anyone with obesity with minimal concern about nutritional inadequacy. The daily caloric intake for women is about 1,200 kcal and for men about 1,400 kcal with no special supplementation or supervision required. On average, expected weight loss is in the order of one pound per week. Low calorie diets average 800 to 1,200 kcal/day for women and 800 to 1,400 kcal/day for men. There is some risk of protein, vitamin and mineral deficiencies, and as such, these diets are reserved for those with moderate or high health risks attributable to obesity. On average, the weight loss is two pounds per week, and a total of 10 to 15 percent of the initial body weight is lost over a period of 10 to 20 weeks. Very low calorie diets are those containing less than 800 kcal/day and, due to the risk of nutritional deficiencies, require strict medical supervision. These diets are reserved for those patients who are at high to extremely high risk, and
INVESTIGATIONS
A vast array of investigations is unnecessary in the examination of obesiry. Testing should not be done routinely but rather should be guided by clinical suspicion, with the two most common assessments being of thyroid function and cortisol production. It is also worthwhile to measure fasting blood glucose, cholesterol and triglycerides, uric acid and liver enzyme levels. Occult complications may be detected by using this simple screen. BUILDING A
MANAGEMENT PLAN
ESTABLISHING URGENCY
Each obese patient is different and, although there are standard treatment methods, individual tailoring must be done in accordance with the overall health risk engendered by the obesity. The two factors to consider when establishing individual risk are the BMI and the
JOURNALSOGC
436
MAY1999
,, , weight losses of up to 20 kg have been seen in as little as 12 weeks. 14,15
of primary pulmonary hypertension and valvular heart disease led to these medications being removed from the market in September 1997. 21,22 At present, the only medications available include two low-abuse catecholaminergic agents (diethylpropion and mazindol) as well as one serotonergic medication (fluoxetine). In the near future, new medications are expected, including orlistat (a non-absorbed lipase inhibitor) and sibutramine (a centrally acting agent with mixed properties).
Diet composition plays an insignificant role in the magnitude of initial weight loss (which is most dependent on total caloric intake), but becomes more important in the maintenance phase. During this phase, it is essential to keep fat intake low and to preserve protein intake in order to stabilize lean body mass. 16 EXERCISE AND CHANGE OF HABITS
Exercise plays an integral role in any weight management programme. Although the weight loss attributable to exercise alone is much less than that of diet alone, the combination is additive and allows for the desired preservation oflean body mass. Exercise is essential in the maintenance of weight loss over time, and has been demonstrated to reduce morbidity and mortality, even in the absence of weight loss, Obese patients should be encouraged to start slowly and gradually to increase intensity to a goal of 1,000 kcal/week of energyexpenditure (approximately 30 minutes of moderate intensity 3 times weekly). 17,18 Altering such habits as a lifelong eating pattern and smoking, and learning specific behaviours including selfmonitoring, problem solving, stress management and relapse prevention techniques all help to improve the overall physical and mental well-being of a patient and allow for more sustainable reductions in weight. 19
THE ROLE OF SURGERY
Surgery is considered a therapy only for morbid obesity associated with an extremely high health risk and only within the context of a well-organized, multidisciplinary programme, incorporating all other methods of promoting weight loss. Patient selection is of paramount importance and exclusions include: active psychiatric or medical disease, or a history of an eating disorder or alcoholism, There are two basic types of surgery for morbid obesity: gastroplasty (vertically banded most commonly) or some form of intestinal bypass (for example ileogastrostomy). The results are highly dependent on the experience of the surgeon and the exact form of surgery performed. On average, the expectation is that between 40 to 70 percent of excess body weight will be lost and kept off for an extended time. Obesityrelated comorbidities including diabetes and hypertension are usually eradicated or at least markedly ameliorated. Complications include postoperative problems (infection, dehiscence), occasional nutritional deficiencies, a proclivity to gallstone and kidney stone formation, dumping syndrome (gastroplasty) and diarrhoea (bypass), 23
THE ROLE OF MEDICATIONS
Medications can occasionally provide a useful adjunct to a well thought out weight management plan, but their use should only be considered as an "add-on" in those patients at high to extremely high health risk from obesity. The first generation of medications were catecholaminergic anorexics that carried a fairly high potential for abuse, Despite reasonable efficacy, this class has fallen out of favour. Second generation medications appeared more promising, with newer, low-abuse potential catecholaminergics and novel serotonergic preparations. In isolation and in combination, such medications as fenfluramine, dexfenfluramine and phenteramine showed great promise in creating and sustaining substantial weight loss, 20 These medications were prescribed widely, but isolated reports and subsequently series of cases
JOURNAL SOGC
BUILDING IN A FEEDBACK LOOP AND MAINTAINING WEIGHT LOSS
As obesity is a chronic, lifelong problem, a well thought out management plan should include clear goals and time lines for re-evaluation,z4 During the initial weight loss phase, periods of three months seem most appropriate in order to evaluate progress and make adjustments as necessary. Once the maintenance phase is reached, periods of six or even twelve months are adequate to ensure reasonable, sustained weight loss. If at
437
MAY 1999
,,, 10. Bennett WI. Beyond overeating. N Engl J Med 1995;332:672-4. 11. Guidance for Treatment of Adult Obesity. Shape Up America and the American Obesity Association, 1996, Bethesda, MD. 12. Lean MED, Han TS, Morrison CE. Waist circumference as a measure for indicating need for weight management. BMJ 1995;311 :158-61. 13. Higgins M, Agostino R, Kannel W, Cobb J. Benefits and adverse effects of weight loss. Observations from the Framingham study. Ann Intern Med 1993; 119(7pt.2):694-7. 14. Hyrnan FN, Sempos E, Saltsman J, Glinsman WH. Evidence for success of caloric restriction in weight loss and control. Summary of data from industry. Ann Intern Med 1993;119(7pt.2):681-7. 15. Wadden, TA. Treatment of obesity by moderate and severe caloric restriction: results of clinical research trials. Ann Intem Med 1993;119(7pt.2):688-93. 16. Hill JO, Drougas H, Peters Jc. Obesity treatment: can diet composition playa role? Ann Intern Med 1993;119(7pt.2):694-7. 17. Blair SN. Evidence for success of exercise in weight loss and control. Ann Intem Med 1993;119(7pt.2):702-6. 18. Pate RR, Pratt M, Blair SN et a/. Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402-7. 19. Foreyt Jp, Goodrick GK. Evidence for success of behavior modification in weight loss and control. Ann Intern Med 1993;119(7pt.2):698-701. 20. Weintraub M, Sundaresan PR, Madan M et a/. Long term weight control study. I) weeks 0 to 34. The enhancement of behavior modification, caloric restriction, and exercise by fenfluramine plus phenteramine versus placebo. Clin Pharmacol Ther 1992;51 :586-94. 21. Curfman GO. Diet pills redux. N Engl J Med 1997;337(9):629-30. 22. Devereux RB. Appetite suppressants and valvular heart disease. N Engl J Med 1998;339(11):765-6. 23. Sagar PM. Surgical treatment of morbid obesity. Br J Surg 1995;82:732-9. 24. NIH Technology Assesment Conference Panel. Methods for voluntary weight loss and control. Ann Intern Med 1993;119(7pt.2):764-70.
any point, the goals are not being met, it is most prudent to start over at the assessment phase and to adjust the goals or the plan. SUMMARY
Obesity is a common and important medical condition that is misunderstood. Because of the serious nature of the complications seen with obesity and its independent association with increased mortality, the public and the medical community should afford this problem a great deal of attention and effort. We estimate (report pending publication in the Canadian Medical Association Journal) that between 1.1 and 4.6 percent of the total direct cost of illness in Canada is due to obesity. Although often frustrating for both patient and physician, the longitudinal management of obesity can pay dividends in the modification of morbidity and mortality, and also in the promotion of a sense of well-being. Thorough assessment and carefully designed weight maintenance programmes should be created on an individual basis in order to offer the best long-term chance of success. REFERENCES 1.
2.
3.
4.
5. 6. 7.
8.
9.
Kuzmarski RJ, Flegal KM, Campbell SM, Johnson CL. Increasing prevalence of overweight among US adults: the National Health and Nutrition Examination Surveys, 1960 to 1991. JAMA 1994;272:205-11. Statistics Canada. Health Status of Canadians: General Social Survey. Ottawa, Ontario, Canada: Supply and Services Canada,1994. Solomon CG, Manson JE. Obesity and mortality: a review of the epidemiologic data. Am J Clin Nutr 1997; 66(suppl): 1044S-50S. Manson JE, Willett WC, Stampfer MJ et a/. Body weight and mortality among women. N Engl J Med 1995;333:677-85. Kushner RF. Body weight and mortality. Nutr Rev 1993;51: 127 -36. National Task Force on the Prevention and Treatment of Obesity. Weight cycling. JAMA 1994;272:1196-1202. Liebel RI, Rosenbaum M, Hirsch J. Changes in energy expenditure resulting from altered body weight. N Engl J Med 1995;332:621-8. Considine RV, Madhur KS, Heiman ML et a/. Serum immunoreactive-Ieptin concentrations in normal weight and obese humans. N Engl J Med 1996;334:292-5. Bruce B, Wilfley D. Binge eating among the overweight population: a serious and prevalent problem. J Am Diet Assoc 1996;96:58-61.
JOURNALSOGC
438
MAY1999
GYNAECOLOGY
WEIGHT
, , , , ,
Loss IN WOMEN
David Kincade, MD, FRCPC, 1 Carl Laird Birmingham, MD, MHSc, FRCPC, ABIM, FACP,2 1Fellow,
Division of General Internal Medicine, University of British Columbia, 2Professor and Head, Division of General Internal Medicine, University of British Columbia, Head, Division of Internal Medicine, Co~Director, Eating Disorders Clinic, St. Paul's Hospital, Vancouver, British Columbia
ABSTRACT
Obesity afflicts many women. In addition to the associated social stigma, obesity contributes to a variety of serious comarbidities and, independently, to mortality. Rational management of obesity requires a thorough assessment far causes and complications and a personalized weight management programme, with the appreciation that this is a chronic disease. As with any chronic condition, long-term foUow-up is required, and there must be a willingness on the part of the doctor and the patient to modify the plan accarding to results and goals. RESUME
Lobesiti afflige beaucoup de femmes. En plus du sentiment de gene qu'elle suscite sur Ie plan social, l'obesiti entraine des comarbidites graves et meme, par elle-meme, Ia mart. Une gestion rationnelle de l'obesiti exige une evaluation approfondie des causes et des complications et un programme de gestion du poids personnalise. II faut comprendre qu'il s'agit ici d'une maladie chronique. Comme pour toute condition chronique, un suivi it long terme est essentiel et Ie medecin et Ia patiente doivent rtre prets it modifier leurs plans selon les resultats et les objectifs.
KEY WORDS Obesity, women. Received on September 29th, 1998. Revised and accepted on November 5th, 1998.
JOURNAL SOGe
434
MAY 1999
,,, INTRODUCTION
Is
OBESITY DUE TO GLUTTONY OR LACK OF
WILLPOWER?
Obesity is defined as an excess of body fat. This excess is usually accepted as being more than 20 percent above the ideal body weight as defined by life insurance tables, or a body mass index greater than the eighty-fifth percentile. Obese patients may present to their physicians with the complaint of excess weight, an eating disorder, or with such a comorbidity as diabetes or hypertension. Morbid obesity is defined as a body fat 100 percent, or more, of normal. This term was coined in the 1950s to help to identify a group of patients whose risk from obesity is so great that obesity surgery may be indicated. Between one-quarter to one-third of adult North American women are overweight. In certain ethnic populations, this figure is substantially higher. 1 Despite the massive effort and billions of dollars spent in Canada and the United States trying to control weight, the prevalence of obesity is increasing among adults. 1,2 TRUTHS AND MYTHS ABOUT OBESITY
Although fat cannot be gained without the ingestion of more calories than are expended, obesity is usually due to a modest degree of overnutrition in someone who is genetically predisposed to gain fat. Many obese people gain at the rate of 10 pounds a year which, if multiplied by 3,500 kilocalories for every pound of fat and divided by 365 days, means that they are ingesting about 100 excess kilocalories a day (equivalent to an apple or one piece of bread). Humans have a "set point" for weight located in the hypothalamus that regulates many functions, including appetite and energy expenditure-which means that the obese are working against homeostatic mechanisms when they are dieting. For example, during dieting the body reduces resting energy expenditure by about a third, thus promoting return of the lost weight. 7 Some evidence suggests that these feedback mechanisms may be mediated in part by leptin (leptin receptors are located in the hypothalamus). 8 Therefore, obesity should be considered a chronic disease.
LIFESPAN AND OBESITY
ASSESSMENT OF THE OBESE PATIENT
In addition to contributing to a variety of conditions including hypertension, dyslipidaemia, diabetes mellitus and some cancers, obesity is independently associated with an increased mortality when compared to non-obese controls. 3-5 For example, a woman between 25 and 35 years of age who is 100 pounds over her ideal weight is 12 times as likely to die as a woman of ideal body weight.
CLINICAL HISTORY
A complete history of the obese patient is necessary to establish potential causes, confounders and complications. It is important to understand the pattern of weight gain in the patient over time in order to predict the expected course of weight change in the years to come. It is useful to learn what an individual weighed at certain stages in life and then to use these weights as standards for comparison. It is important to establish if there is any past history or current symptomatology of an eating disorder. Anorexia, bulimia and binge eating disorder all greatly complicate management. 9,10 A search for symptoms of hypothyroidism (lethargy, dry skin, cold intolerance, menometrorrhagia) or hypercortisolism (central weight gain, easy bruiSing, purplish abdominal striae, moon facies, buttock wasting) may prove helpful when considering secondary causes. Medications including estrogens, steroids and psychiatric medications may cause weight gain. Their use should be noted. A thorough review of systems may
WEIGHT CYCLING
There is a misconception in the lay (and medical) literature that weight cycling, or so-called "yo-yo dieting," leads to permanent detrimental physiological and psychological changes in the obese person. A thorough evaluation of available evidence failed to corroborate permanent changes in metabolism, deleterious effects on psychological profiles or in overall morbidity and mortality in patients who weight cycle. 6 Because of the negative consequences of obesity, we should continue to encourage weight loss, despite the inability of a substantial number of people to maintain it.
JOURNAL SOGC
435
MAY 1999
,,, presence or absence of medical complications. All obese patients exist on a spectrum ranging from low health risk (BMI <30 and an absence of medical complications) to extremely high health risk (BMI 35-40 with complications or BMI >40 even in the absence of complications). 11 It is of the utmost importance to place individuals within this spectrum in order to design an appropriate weight management plan.
reveal a variety of complications attributable to obesity (hypertension, diabetes mellitus, coronary artery disease, sleep apnoea, dyslipidaemia, arthritis, gallstones). The patient's functional capacity and the degree of debility associated with the obesity should be established. PHYSICAL EXAMINATION
The physical examination is focused initially on the documentation and quantification of obesity. In addition to measuring the weight and height, the body mass index (BMI) and the waist to hip ratio (WHR) can be quantified. The BMI is calculated by dividing the height in metres by the square of the weight in kilograms. A normal BMI is between 21 and 27, and overweight is defined as a BMI greater than 27.11 The waist to hip ratio is a simple tool for assessing fat distribution. Ratios of> 1.0 in men and >0.8 in women signify "apple" or android obesity which correlates with a risk to health beyond that suggested by weight alone. 11 Simple waist circumference has predictive value, and a measurement of >40 inches in a male or >35 inches in a female is considered a marker of increased risk. 12 The remainder of the examination is a search for corroborating physical evidence to support a potential secondary cause of obesity and signs of any medical complications.
SETTING GOALS
The most important factor before embarking on a longitudinal, often complex, weight management strategy is to assess patient readiness. Without complete patient involvement, even the best intentioned plans are doomed to fail. Once the patient has demonstrated willingness to proceed, it is important to set realistic, attainable and sustainable goals for weight. For most patients, especially those with a BMI >30, a target BMI two below their current one is both realistic and practical. A weight loss of this magnitude leads to improvement in comorbid conditions, albeit in the absence of a clear improvement in longevity. 13 DIET
It is necessary to establish an energy deficit in order to generate weight loss. A reasonable goal is to aim for a deficit of about 500 kcal per day, which is generally sustainable and palatable to the patient. Moderate deficit diets can be prescribed to anyone with obesity with minimal concern about nutritional inadequacy. The daily caloric intake for women is about 1,200 kcal and for men about 1,400 kcal with no special supplementation or supervision required. On average, expected weight loss is in the order of one pound per week. Low calorie diets average 800 to 1,200 kcal/day for women and 800 to 1,400 kcal/day for men. There is some risk of protein, vitamin and mineral deficiencies, and as such, these diets are reserved for those with moderate or high health risks attributable to obesity. On average, the weight loss is two pounds per week, and a total of 10 to 15 percent of the initial body weight is lost over a period of 10 to 20 weeks. Very low calorie diets are those containing less than 800 kcal/day and, due to the risk of nutritional deficiencies, require strict medical supervision. These diets are reserved for those patients who are at high to extremely high risk, and
INVESTIGATIONS
A vast array of investigations is unnecessary in the examination of obesiry. Testing should not be done routinely but rather should be guided by clinical suspicion, with the two most common assessments being of thyroid function and cortisol production. It is also worthwhile to measure fasting blood glucose, cholesterol and triglycerides, uric acid and liver enzyme levels. Occult complications may be detected by using this simple screen. BUILDING A
MANAGEMENT PLAN
ESTABLISHING URGENCY
Each obese patient is different and, although there are standard treatment methods, individual tailoring must be done in accordance with the overall health risk engendered by the obesity. The two factors to consider when establishing individual risk are the BMI and the
JOURNALSOGC
436
MAY1999
,, , weight losses of up to 20 kg have been seen in as little as 12 weeks. 14,15
of primary pulmonary hypertension and valvular heart disease led to these medications being removed from the market in September 1997. 21,22 At present, the only medications available include two low-abuse catecholaminergic agents (diethylpropion and mazindol) as well as one serotonergic medication (fluoxetine). In the near future, new medications are expected, including orlistat (a non-absorbed lipase inhibitor) and sibutramine (a centrally acting agent with mixed properties).
Diet composition plays an insignificant role in the magnitude of initial weight loss (which is most dependent on total caloric intake), but becomes more important in the maintenance phase. During this phase, it is essential to keep fat intake low and to preserve protein intake in order to stabilize lean body mass. 16 EXERCISE AND CHANGE OF HABITS
Exercise plays an integral role in any weight management programme. Although the weight loss attributable to exercise alone is much less than that of diet alone, the combination is additive and allows for the desired preservation oflean body mass. Exercise is essential in the maintenance of weight loss over time, and has been demonstrated to reduce morbidity and mortality, even in the absence of weight loss, Obese patients should be encouraged to start slowly and gradually to increase intensity to a goal of 1,000 kcal/week of energyexpenditure (approximately 30 minutes of moderate intensity 3 times weekly). 17,18 Altering such habits as a lifelong eating pattern and smoking, and learning specific behaviours including selfmonitoring, problem solving, stress management and relapse prevention techniques all help to improve the overall physical and mental well-being of a patient and allow for more sustainable reductions in weight. 19
THE ROLE OF SURGERY
Surgery is considered a therapy only for morbid obesity associated with an extremely high health risk and only within the context of a well-organized, multidisciplinary programme, incorporating all other methods of promoting weight loss. Patient selection is of paramount importance and exclusions include: active psychiatric or medical disease, or a history of an eating disorder or alcoholism, There are two basic types of surgery for morbid obesity: gastroplasty (vertically banded most commonly) or some form of intestinal bypass (for example ileogastrostomy). The results are highly dependent on the experience of the surgeon and the exact form of surgery performed. On average, the expectation is that between 40 to 70 percent of excess body weight will be lost and kept off for an extended time. Obesityrelated comorbidities including diabetes and hypertension are usually eradicated or at least markedly ameliorated. Complications include postoperative problems (infection, dehiscence), occasional nutritional deficiencies, a proclivity to gallstone and kidney stone formation, dumping syndrome (gastroplasty) and diarrhoea (bypass), 23
THE ROLE OF MEDICATIONS
Medications can occasionally provide a useful adjunct to a well thought out weight management plan, but their use should only be considered as an "add-on" in those patients at high to extremely high health risk from obesity. The first generation of medications were catecholaminergic anorexics that carried a fairly high potential for abuse, Despite reasonable efficacy, this class has fallen out of favour. Second generation medications appeared more promising, with newer, low-abuse potential catecholaminergics and novel serotonergic preparations. In isolation and in combination, such medications as fenfluramine, dexfenfluramine and phenteramine showed great promise in creating and sustaining substantial weight loss, 20 These medications were prescribed widely, but isolated reports and subsequently series of cases
JOURNAL SOGC
BUILDING IN A FEEDBACK LOOP AND MAINTAINING WEIGHT LOSS
As obesity is a chronic, lifelong problem, a well thought out management plan should include clear goals and time lines for re-evaluation,z4 During the initial weight loss phase, periods of three months seem most appropriate in order to evaluate progress and make adjustments as necessary. Once the maintenance phase is reached, periods of six or even twelve months are adequate to ensure reasonable, sustained weight loss. If at
437
MAY 1999
,,, 10. Bennett WI. Beyond overeating. N Engl J Med 1995;332:672-4. 11. Guidance for Treatment of Adult Obesity. Shape Up America and the American Obesity Association, 1996, Bethesda, MD. 12. Lean MED, Han TS, Morrison CE. Waist circumference as a measure for indicating need for weight management. BMJ 1995;311 :158-61. 13. Higgins M, Agostino R, Kannel W, Cobb J. Benefits and adverse effects of weight loss. Observations from the Framingham study. Ann Intern Med 1993; 119(7pt.2):694-7. 14. Hyrnan FN, Sempos E, Saltsman J, Glinsman WH. Evidence for success of caloric restriction in weight loss and control. Summary of data from industry. Ann Intern Med 1993;119(7pt.2):681-7. 15. Wadden, TA. Treatment of obesity by moderate and severe caloric restriction: results of clinical research trials. Ann Intem Med 1993;119(7pt.2):688-93. 16. Hill JO, Drougas H, Peters Jc. Obesity treatment: can diet composition playa role? Ann Intern Med 1993;119(7pt.2):694-7. 17. Blair SN. Evidence for success of exercise in weight loss and control. Ann Intem Med 1993;119(7pt.2):702-6. 18. Pate RR, Pratt M, Blair SN et a/. Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402-7. 19. Foreyt Jp, Goodrick GK. Evidence for success of behavior modification in weight loss and control. Ann Intern Med 1993;119(7pt.2):698-701. 20. Weintraub M, Sundaresan PR, Madan M et a/. Long term weight control study. I) weeks 0 to 34. The enhancement of behavior modification, caloric restriction, and exercise by fenfluramine plus phenteramine versus placebo. Clin Pharmacol Ther 1992;51 :586-94. 21. Curfman GO. Diet pills redux. N Engl J Med 1997;337(9):629-30. 22. Devereux RB. Appetite suppressants and valvular heart disease. N Engl J Med 1998;339(11):765-6. 23. Sagar PM. Surgical treatment of morbid obesity. Br J Surg 1995;82:732-9. 24. NIH Technology Assesment Conference Panel. Methods for voluntary weight loss and control. Ann Intern Med 1993;119(7pt.2):764-70.
any point, the goals are not being met, it is most prudent to start over at the assessment phase and to adjust the goals or the plan. SUMMARY
Obesity is a common and important medical condition that is misunderstood. Because of the serious nature of the complications seen with obesity and its independent association with increased mortality, the public and the medical community should afford this problem a great deal of attention and effort. We estimate (report pending publication in the Canadian Medical Association Journal) that between 1.1 and 4.6 percent of the total direct cost of illness in Canada is due to obesity. Although often frustrating for both patient and physician, the longitudinal management of obesity can pay dividends in the modification of morbidity and mortality, and also in the promotion of a sense of well-being. Thorough assessment and carefully designed weight maintenance programmes should be created on an individual basis in order to offer the best long-term chance of success. REFERENCES 1.
2.
3.
4.
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