Review Article
OBESITY: A MODERN DAY PLAGUE
Maj YATENDRA KUMAR YADAV ABSTRACT Obesity Is the presence of excess body fat. Unfortunately obesity Is taken as a mere cosmetic problem and not a medical one. Today obesity Is being 'dealt' with more by the self-proclaimed fitness experts running the rapidly mushrooming fitness centres rather than by medical professionals. But rather than merely a cosmetic problem, obesity should be viewed as a disease because there are multiple biologic hazards at surprisingly low levels of excess faL With the rapid pace of industrialisation and economic progress, today more and more jobs are becoming sedentary and dietary patterns are also changing with a decline in the cereal intake and Increase in the intake of sugar and fats. However, inherited physiologic differences in response to eating and exercise are also important factors. Treating obesity can often be a frustrating experience for both the physician and the patient because of the great difficulty in maintaining weight loss over the long term. However, a clear understanding of the causes of obesity and a treatment strategy based on a combination of diet, nutrition, education, exercise, behaviour modification and social support can go a long way in containing this 'modem day plague' before it acquires epidemic proportions.
MJAFI 2002; 58: 60-65 KEY WORDS:Appetite suppressants; Body mass Index (BMI); Leptfn; Low calorie diets (LeOs); Resting metaboUc rate (RMR).
Introduction
O
besity is the presence of excess body fat and is associated with a variety of medical conditions, which increase morbidity and mortality. In fact it is now argued rather convincingly that obesity is an independent and powerful heart disease risk factor that may be equal to that of smoking, elevated blood lipids and hypertension. In 1998, the American Heart Association announced the addition of obesity to its list of major risk factor that people can control to prevent death and disability from coronary heart disease [1]. Obesity is a serious and increasingly prevalent health problem. The Lancet, a highly respected medical journal, called obesity a "time bomb that is ticking away". Health risks associated with Obesity The major health risks of obesity increase in a curvilinear relationship, with prevalences increasing progressively and disproportionately with increasing weight. Co-morbidities or complications associated with obesity include :a. Type n diabetes mellitus b. Hypertension c. Coronary artery disease. d. Stroke
e.
Pulmonary Abnormalities - Obstructive sleep apnoea, Pickwickian syndrome.
f.
Gall bladder disease - increased incidence of
Cholelithiasis [2]. g. Osteo-arthritis of the weight bearing joints [2]. h. Gout. 1.
Incidence of cancer-overweight men have a significantly higher mortality rate for colorectal and prostrate cancer. Obese females have a higher mortality from cancer of gallbladder, biliary passages, breast, uterus and ovaries.
j.
Reduced fertility.
k. Increased risk of accidents. I.
Impaired obstetric performance.
m. Abnormal plasma lipid and lipoprotein concentration. n. Psychological disorders - Impairment in body image is the major form of psychological disturbance specific to obese persons. Feelings of rejection, shame or depression are common [3]. Causes of Obesity Etiology of obesity is still largely unknown. However, the increased prevalence of over weight is paralleled by an increase in inactivity. Most jobs today are sedentary [4]. Automobiles, public transportation. television and other labour saving devices also contribute to sluggish lifestyles . Changes in dietary patterns are also a probable factor. As the population ascends the socio-economic scale, cereal intake declines and intake of sugar and fats generally increases.
Specialist in Sports Medicine. Head Quarters. Indian Military Training Team. C/o 99 APO.
61
Obesity
As economic progress and globalisation spread, so do waistlines. Although these factors undoubtedly play a role in obesity, inherited physiologic differences in response to eating and exercise are also involved. It is a complex disorder of appetite regulation and energy metabolism.
Set Point Theory The proponents of a set point theory argue that the body has an internal control mechanism, a set point, probably located deep within the brain's lateral hypothalamus that drives the body to maintain a particular level of body fat [5]. Genetic factors : Studies of families, adoptees and twins have demonstrated the inheritability of human obesity [6]. Recently obesity gene has been identified. The obesity gene located in adipose tissue, codes for a circulating satiety factor, leptin, which acts on the hypothalamus. Two different genetic models of obesity have been demonstrated in mice - one of defective leptin production [7] and the other of defective leptin receptor action [8], which has also been documented in human beings. Studies of obese humans suggest that insensitivity to leptin may be one factor in the development of human obesity. There is also evidence that chronic high intake of fat leads to leptin resistance and increased adiposity [7]. Metabolic factors: Relatively low RMR and lower rate of fat oxidation are risk factors for the development of obesity [9]. Studies have also shown that there is considerable individual variation in rates of carbohydrate and fat oxidation, independent of metabolic rate. Psychological factors : Psychological factors also may influence eating habits. Many people eat in response to negative emotions such as boredom, sadness or anger. Other causes: Some rare illnesses can cause obesity. These include hypothyroidism, Cushing's syndrome, depression and certain neurological problems that can lead to overeating. Certain drugs such as steroids and some antidepressants may cause weight gain. But these are believed to be responsible for only about I% of all causes of obesity.
Criteria for Obesity: How fat is too fat The terms "Overweight" and "Obesity" have different though related meanings. Overweight refers to an excess of total body weight that includes all tissues and water. Obesity is defined specially as an excess of body fat. When total body fat is used as an index of MJAFI. VOL 58. NO. I. 1002
obesity, men with more than 25% and women with more than 30% of body fat are considered obese. The most clinically relevant methods of indirectly assessing obesity are the weight for height tables and BMI. A BMI of 25 and over is an indication of being overweight while 30 is a measure of obesity. However, in a meet of regional experts in Hong Kong recently, new set of guidelines have been launched for Asia-Pacific region to diagnose obesity. The new guidelines, endorsed by the WHO, set a lower cut off level more appropriate for the smaller framed Asian population. The new Asia-Pacific guidelines set the cut off level at 23. However, these methods are not suitable for assessing body composition changes in athletes. A heavily muscled athlete may be overweight with any of these indices and have a very low fat content. To determine whether an individual is obese or simply overweight because of increased muscle mass, one needs techniques for quantitating body fat. In them, measurement of body lean/fat ratios requires one of several procedures such as skin fold thickness, underwater weighing, bioelectric impedance, measurement of total body potassium and imaging techniques like CT, ultrasound or MRI scan.
Regional fat distribution Apart from BMI, there are other factors to reckon within the domain of obesity. The patterning of adipose tissue distribution, independent of total body fat alters the health risk of obesity, e.g. increased abdominal fat defined as waist to hip ratio greater than 0.9 in men and 0.8 in women, carries an even higher and independent risk for type II diabetes, hypertension, stroke and heart disease, plus an increased overall mortality rate [10, II J. This is because excess fat in the abdominal area (central or android type obesity) is more active metabolically than fat located in the hips and thighs (peripheral or gynoid type obesity) and thus more capable of entering into processes related to heart disease.
Treatment Who should lose weight? Doctors generally agree that people who are 20% or more overweight, especially the severely obese persons, can gain significant health benefits from weight loss. Many obesity experts believe that people who are less than 20% above their healthy weight should try to lose weight if they have any of the following risk factors: (a) Family history of heart disease or diabetes.
62
(b) Pte-existing medical conditions - like high blood pressure, high cholesterol levels or high blood sugar levels. (c) "Apple" shape i.e. central or android type of obesity. Treatment of obesity often entails frustration for both physician and patient because of the great difficulty in maintaining weight loss over the long term. Regardless of the weight loss method used, there is a strong tendency to regain weight. Most people regain as much as two thirds of their lost weight by one year post treatment and almost all of the weight by 5 years [10]. Following weight loss, the major structural change in adipose cellularity is shrinkage in fat cell size with no change in cell number. This suggests that formerly obese persons are not really "cured" of their obesity, at least in terms of the total number of fat cells present. It is because of this that formerly obese patients have an extremely difficult time maintaining their new body size. Also, it appears that when obese people lose body mass the fat cells increase their level of lipoprotein lipase, the enzyme that facilitates fat synthesis and storage. The effect of these high enzyme levels is to make it easier for formerly obese to regain fat. Clinical examination should aim at identifying previously undiagnosed chronic illnesses or co-morbidities of obesity. Laboratory testing for secondary causes of obesity like hypothyroidism is based on physician's judgement in each individual case. (a) Setting a goal - establishing a reasonable weight loss goal is critical. The "goal weight" may have nothing to do with "ideal weight". The goal should be defined ultimately by what is realistic and effective in reducing the health risks or complications associated with obesity. (b) Criteria for success - must include not only pounds lost but other objective and subjective measures of improved well being, such as lower blood pressure, an improved lipid profile, better blood glucose control, less back pain, more energy or greater mobility. Establish medical goals for weight loss and tie success to these end points. (c) Patient education - patients may feel that their obesity is the result of character flaws such as gluttony or laziness. Patients need to be educated about the etiology of obesity and explained that development of obesity is a result of complex genetic and environmental factors. By correcting his misconceptions in a scientific and non-judgemental fashion, the practitioner can minimise the guilt and self-defeating thoughts
Yadav
that often block success.
Treatment options Like treatment for hypertension or diabetes, treatment for obesity requires life long therapy. The most effective weight loss programs combine diet, nutrition, education, exercise, behaviour modification and social support. Diet/Nutrition education First step towards planning a diet most appropriate for weight loss is to keep food records and become aware of what, when and how much they eat. Second step is to know how many calories per day are appropriate to eat. To roughly estimate caloric needs for weight maintenance, multiply the desired weight by 12-15 caVlb for moderate activity; 15-20 cal/lb for higher levels of activity. The actual requirement will vary depending upon individual metabolic differences. Third step is to determine the number of calories appropriate for weight reduction by subtracting 300 to 1000 caVd. Divide the number into three and you will have a calorie target for each meal. It is also important to recommend a low fat diet in the treatment of obesity. instead of focusing solely on control of total calories. However, at times more radical measures such as LCDs comprising 800-1000 kcaVd or very low calorie diets (VLCDs) comprising 400-600 kcaVd need to be adopted. Exercise and lifestyle activity The possibility of a genetically low resting metabolic rate increases the importance of exercise to raise use and offset the factors encouraging weight regain. Enhanced physical activity can play an important role in helping overweight patients both lose and manage their weight. Longitudinal and cross sectional studies have consistently reported that physical activity is inversely related to weight [12]. Simply having patients increase their level of exercise without restricting calorie intake is a relatively ineffective way to lose weight. When combined with a healthy diet, increased aerobic and strength training may result in optimal changes in body composition by contributing to a negative energy balance and preserving lean body mass [13]. Effects of enhanced physical activity, other than on body composition, include a reduction in blood pressure, increased sensitivity to insulin, improved lipoprotein profile and an increase in physical fitness [14]. However, so far there is little or no evidence that exercise programs can affect abdominal or visceral fat content [15]. Exercise will benefit patients even if they do not MJAFI, VOl.. $8. NO. I, 2002
Obesity
lose weight. Various studies have shown that an unfit lean man has double risk of all cause mortality when compared with a fit lean man. Unfit lean man also has a higher risk of all cause and cardiovascular disease mortality than did man who was fit and obese [16]. In addition patients who exercise regularly are likely to be less depressed, have higher self esteem and have an improved body image. Any activity aimed at weight reduction must involve large muscle groups to induce large energy expenditure. Examples include walking, cycling, swimming, dancing, cross country skiing, skating, basketball and soccer [14]. Barriers to Activity
Inspite of many patients recognizing that regular exercise is important from both health and weight management perspectives, very few of them participate in regular exercise programs [17]. A survey of overweight sedentary patients has shown four greatest barriers to regular activity :- Lack of time - Embarrassment at taking part in activity. - Inability to exercise vigorously - Lack of enjoyment of exercise. A lack of time has consistently been reported as the greatest obstacle to being active. In this background, new strategies to promote physical activity are being explored that stray from the classic exercise prescription of at least 30 minutes of uninterrupted vigorous activity done 3 or more days per week. The American College of Sports Medicine (ACSM) and the Centre for Disease Control and prevention have recommended that all patients should attempt to accumulate 30 minutes or more of moderate intensity physical activity on most or preferably all days [18]. The aim is to offer a greater range of choices for sedentary people, especially those who do not enjoy traditional activity. Three 10 minute bouts of aerobic exercise yield fitness improvements comparable to, though slightly less than, those from one continuous 30 minute session [13,19]. Moreover, the strategy of splitting up the workouts may result in better exercise adherence and increased weight loss [20]. The concept of "lifestyle activity" encourages patients to look for opportunities everyday to increase energy expenditure. A few examples for increasing daily energy expenditure are :- Parking the car at the far end of the parking lot. - Gardening, raking leaves, and mowing the lawn. - Housework such as cleaning, vacuuming. dusting MJAFI. VOL 58. NO. 1.2002
63
and dish washing. - Using stairs and walking whenever possible rather than using elevators, escalators and moving walks. - Walking during lunch breaks. - Using fewer labour saving devices such as remote controls. - Playing with or baby-sitting toddlers. Focusing on lifestyle activity may be a suitable initial exercise program for an obese patient who finds it difficult to comply with a vigorous exercise regimen or for those who do not have time for a traditional exercise program or those who do not enjoy exercise [13]. The exercise prescription for the obese individual who is ready to start a traditional exercise program should involve not only cardio-respiratory fitness enhancement, but also strength training, lifestyle activity and flexibility exercises. ACSM recommends aerobic exercise 20 to 60 minutes (which can be broken into 10 minute bouts) 3 to 5 days per week, resistance training 2 to 3 days per week, and flexibility training 2 to 3 days per week [13,21]. Behaviour modification Behaviour modification techniques are also important and helpful adjuncts and include: - Stimulus control - e.g. keeping food out of sight, eating only at specific times and places, and layout your exercise clothes to remind you to do physical activity. - Eating management - e.g. eating slowly. - Behaviour substitution - e.g. when angry or feeling dull, exercising instead of sitting at home and eating. - Self monitoring - using food and exercise diaries. - Rewards - reward yourself for changes such as reducing grams of fat or increasing minutes of exercise. - Stress management - reduce or cope with stress by exercising regularly, meditating, or learning relaxation techniques. - Cognitive-behavioral strategies - e.g. identify your unrealistic expectations and focus on changing your attitudes and beliefs. Talk about yourself positively, imagine yourself eating well and exercising regularly. - Social support - use family and friends as a source of support for encouragement and positive reinforcement of your goals. Pharmacological treatment of Obesity Drug therapy is recommended as a treatment for
Yadav
64
persons with (A) BMI greater than or equal to 30 with no obesity related conditions or (B) BMI of equal to or greater than 27 with two or more obesity related conditions. Anti-obesity drugs are designed to be part of comprehensive weight-loss program that includes regular exercise and a low-fat, low calorie diet. Currently the three weight loss drugs, approved by the US Food and Drug Administration (FDA) for treating obesity, areOrlistat - Approved by the FDA in April 1999,orlistat is the first drug in a new class of anti-obesity drugs that works by blocking the body's absorption of dietary fat. Orlistat works in the gastrointestinal tract, blocking the digestive enzyme pancreatic lipase, reducing absorption of fat by the intestine. Phentermine - an appetite suppressant, has been available for many years. It is half of the "fen-phen" combination (Fenfluramine or Dexfenfluramine plus Phentermine) that remains available for use. It increases availability of brain chemical norepinephrine, inhibits appetite. The use of phentermine alone has not been associated with adverse health effects of the fenfluramine-phentermine combination. Sibutramine - (Sibutramine hydrochloride monohydrate) represents the fist in a new class of anti-obesity drugs known as "neurotransmitter uptake inhibitors." It increases availability of brain chemicals norepinephrine and serotonin and inhibits appetite. Sibutramine is the only appetite suppressant medication approved for longer-term use in significantly obese patients, although the safety and effectiveness have not been established for use beyond one year. The two popular appetite suppressants, fenfluramine and Dex fenfluramine were removed from the market in Sep 1997 after studies strongly suggested that they could damage the heart's mitral valve [22,23]. Weight loss drugs on the horizon
Leptin - This brain chemical (neuropeptide) works by suppressing appetite. Cholecystokinin boosters - Cholecystokinin is a brain chemical believed to produce the feeling of fullness.
Surgical treatment Surgery is recommended for weight loss in certain severely obese patients who haven't responded to less invasive treatments. People with a BMI over 40 or people with BMI over 35 with medical complications are considered candidates for surgery. Surgical proce-
dures to help control obesity generally are divided into two categories: (1) restrictive (2) combined restrictive and malabsorptive. Restrictive Surgery - uses bands or staples to create food intake restsriction. There are two operative procedures in this - Vertical Banded Gastroplasty and Gastric Banding. Combined Restrictive and Malabsorptive Surgery is a combination of restrictive surgery (stomach pouch) with bypass or malabsorptive surgery, in which the stomach is connected to the jejunum or ileum of the small intestine, bypassing the duodenum. There are two operative procedures in this -Roux-en- Y Gastric Bypass and Biliopancreatic Diversion [24]. Other Procedures - Other procedures for weight loss, which are usually not recommended, include jaw wiring and liposuction. References 1. Eckel RH, Krauss RM. American Heart Association call to action : Obesity as a major risk factor for coronary heart disease. AHA Nutrition committee. Circulation 1998; 97(21): 2099-100. 2. Bray GA. Health hazards of obesity. Endocrinology and Metabolism Clinics of North America 1996;25:907-19. 3. Charles SO, Blumberg P. Assessment of psychiatric status among morbidity obese. Obs Bariatr Med 1982;11:71-8. 4. Anderson RE, Blair SN. Cheksin U. Encouraging patients to become more physically active: the physician's role. Ann Intern Med 1997;121(5):395-400. 5. William D McArdle. Frank I. Katch. Victor L Katch. Obesity and weight control : Exercise Physiology. 3rded. Malvern. Lea and Febiger 1991;656-97. 6. Bouchard C. Genetic factors in obesity. Med Clin North Am 1989;73(1 )61-81. 7. Behme MT. Leptin:produet of the obese gene. Nutr Today 1996;31(4): 138-41. 8. Considine RV. Sinha MK, Heiman ML. Serum immunoreactive-Ieptin concentrations in normal weight and obese humans. N Engl J Med 1996;334(5):292-5. 9. Ravussin E, Swinburn B. Energy metabolism. In:Stunkard nded. AJ. Wadden TA, editors. Obesity:Theory and Therapy, 2 New York City: Raven Press, 1993;97-124. 10. Speer SJ, Speer AJ. Office-based treatment of adult obesity. The Physician and Sports medicine 1997;25(4):94-107. 11. Kissebah AH, Freedman OS. Peiris AN. Health risks of obesity. Med Clin North Am 1989;73(1):111-38. 12. Grilo CM, Brownell KD. Stunkard AJ. The metabolic and physiologic importance of exercise in weight control. In:Stunkard AJ, Wadden TA, editors. Obesity:Theory and nded. Therapy, 2 New York City:Raven Press, 1993;253-73. 13. Rose E Anderson. Exercise, an active lifestyle. and obesity:making the exercise prescription work. The Physician and Sports Medicine. 1999;27( 10):41-50. 14. Oded Bar-Or. Juvenile obesity, physical activity and lifestyle MJAFI. VOL 58, NO. 1.20(}2
Obesity changes: cornerstones for prevention and management The Physician and Sports Medicine 2000;28( II ):51-8. 15. Treuth MS. Hunter GR. Figueroa-Colon R. Effects of strength training on intra-abdominal adipose tissue in obese prepubertal girls. Med Sci Sports Exerc 1998:30(12)1738-43. 16. Lee CD. Blair SN, Jackson AS. Cardio respiratory fitness. body composition and all cause and cardiovascular disease mortality in men. Am J Clin Nutr 1999:69(3):373-80. 17. Rose E Anderson. What can physicians do about obesity? The Physician and Sports medicine 2000;28(10):15-6. 18. Pate RR. Pratt M, Blair SN. 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(5):402-07. 19. Andersen RE. Waden TA. Bartlett SJ. Effects of lifestyle activity vs structured aerobic exercise in obese women : a randomized trial. JAMA 1999:281(4):335-40.
6S 20. Jakicic JM, Winters C, Lang W. Effects of intermittent exercise and use of home exercise equipment on adherence. weight loss. and fitness in overweight women: a randomized trial. JAMA 1999:282(16): 1554-60. 21. Pollock ML. Gaesser GA. Butcher JD. The recommended quantity and quality of exercise for developing and maintaining cardio respiratory and muscular fitness and flexibility in healthy adults. Med Sci Sports Exerc 1998;30(6):975-91. 22. Connolloy HM. Grary JL, MC Goon MD. Valvular heart disease associated with fenfluramine-phentermine. N Eng J Med 1997;337:581-8. 23. Abenhaim L, Moride Y. Brenot F. Appetite suppressant drugs and the risk of primary pulmonary hypertension. N Eng J Med 1996;1121:609-16. 24. Karl JG. Surgical treatment of obesity. Med Clin North Am 1989;73 :251-64.
OBESITY: A MODERN DAY PLAGUE
Maj YATENDRA KUMAR YADAV ABSTRACT Obesity Is the presence of excess body fat. Unfortunately obesity Is taken as a mere cosmetic problem and not a medical one. Today obesity Is being 'dealt' with more by the self-proclaimed fitness experts running the rapidly mushrooming fitness centres rather than by medical professionals. But rather than merely a cosmetic problem, obesity should be viewed as a disease because there are multiple biologic hazards at surprisingly low levels of excess faL With the rapid pace of industrialisation and economic progress, today more and more jobs are becoming sedentary and dietary patterns are also changing with a decline in the cereal intake and Increase in the intake of sugar and fats. However, inherited physiologic differences in response to eating and exercise are also important factors. Treating obesity can often be a frustrating experience for both the physician and the patient because of the great difficulty in maintaining weight loss over the long term. However, a clear understanding of the causes of obesity and a treatment strategy based on a combination of diet, nutrition, education, exercise, behaviour modification and social support can go a long way in containing this 'modem day plague' before it acquires epidemic proportions.
MJAFI 2002; 58: 60-65 KEY WORDS:Appetite suppressants; Body mass Index (BMI); Leptfn; Low calorie diets (LeOs); Resting metaboUc rate (RMR).
Introduction
O
besity is the presence of excess body fat and is associated with a variety of medical conditions, which increase morbidity and mortality. In fact it is now argued rather convincingly that obesity is an independent and powerful heart disease risk factor that may be equal to that of smoking, elevated blood lipids and hypertension. In 1998, the American Heart Association announced the addition of obesity to its list of major risk factor that people can control to prevent death and disability from coronary heart disease [1]. Obesity is a serious and increasingly prevalent health problem. The Lancet, a highly respected medical journal, called obesity a "time bomb that is ticking away". Health risks associated with Obesity The major health risks of obesity increase in a curvilinear relationship, with prevalences increasing progressively and disproportionately with increasing weight. Co-morbidities or complications associated with obesity include :a. Type n diabetes mellitus b. Hypertension c. Coronary artery disease. d. Stroke
e.
Pulmonary Abnormalities - Obstructive sleep apnoea, Pickwickian syndrome.
f.
Gall bladder disease - increased incidence of
Cholelithiasis [2]. g. Osteo-arthritis of the weight bearing joints [2]. h. Gout. 1.
Incidence of cancer-overweight men have a significantly higher mortality rate for colorectal and prostrate cancer. Obese females have a higher mortality from cancer of gallbladder, biliary passages, breast, uterus and ovaries.
j.
Reduced fertility.
k. Increased risk of accidents. I.
Impaired obstetric performance.
m. Abnormal plasma lipid and lipoprotein concentration. n. Psychological disorders - Impairment in body image is the major form of psychological disturbance specific to obese persons. Feelings of rejection, shame or depression are common [3]. Causes of Obesity Etiology of obesity is still largely unknown. However, the increased prevalence of over weight is paralleled by an increase in inactivity. Most jobs today are sedentary [4]. Automobiles, public transportation. television and other labour saving devices also contribute to sluggish lifestyles . Changes in dietary patterns are also a probable factor. As the population ascends the socio-economic scale, cereal intake declines and intake of sugar and fats generally increases.
Specialist in Sports Medicine. Head Quarters. Indian Military Training Team. C/o 99 APO.
61
Obesity
As economic progress and globalisation spread, so do waistlines. Although these factors undoubtedly play a role in obesity, inherited physiologic differences in response to eating and exercise are also involved. It is a complex disorder of appetite regulation and energy metabolism.
Set Point Theory The proponents of a set point theory argue that the body has an internal control mechanism, a set point, probably located deep within the brain's lateral hypothalamus that drives the body to maintain a particular level of body fat [5]. Genetic factors : Studies of families, adoptees and twins have demonstrated the inheritability of human obesity [6]. Recently obesity gene has been identified. The obesity gene located in adipose tissue, codes for a circulating satiety factor, leptin, which acts on the hypothalamus. Two different genetic models of obesity have been demonstrated in mice - one of defective leptin production [7] and the other of defective leptin receptor action [8], which has also been documented in human beings. Studies of obese humans suggest that insensitivity to leptin may be one factor in the development of human obesity. There is also evidence that chronic high intake of fat leads to leptin resistance and increased adiposity [7]. Metabolic factors: Relatively low RMR and lower rate of fat oxidation are risk factors for the development of obesity [9]. Studies have also shown that there is considerable individual variation in rates of carbohydrate and fat oxidation, independent of metabolic rate. Psychological factors : Psychological factors also may influence eating habits. Many people eat in response to negative emotions such as boredom, sadness or anger. Other causes: Some rare illnesses can cause obesity. These include hypothyroidism, Cushing's syndrome, depression and certain neurological problems that can lead to overeating. Certain drugs such as steroids and some antidepressants may cause weight gain. But these are believed to be responsible for only about I% of all causes of obesity.
Criteria for Obesity: How fat is too fat The terms "Overweight" and "Obesity" have different though related meanings. Overweight refers to an excess of total body weight that includes all tissues and water. Obesity is defined specially as an excess of body fat. When total body fat is used as an index of MJAFI. VOL 58. NO. I. 1002
obesity, men with more than 25% and women with more than 30% of body fat are considered obese. The most clinically relevant methods of indirectly assessing obesity are the weight for height tables and BMI. A BMI of 25 and over is an indication of being overweight while 30 is a measure of obesity. However, in a meet of regional experts in Hong Kong recently, new set of guidelines have been launched for Asia-Pacific region to diagnose obesity. The new guidelines, endorsed by the WHO, set a lower cut off level more appropriate for the smaller framed Asian population. The new Asia-Pacific guidelines set the cut off level at 23. However, these methods are not suitable for assessing body composition changes in athletes. A heavily muscled athlete may be overweight with any of these indices and have a very low fat content. To determine whether an individual is obese or simply overweight because of increased muscle mass, one needs techniques for quantitating body fat. In them, measurement of body lean/fat ratios requires one of several procedures such as skin fold thickness, underwater weighing, bioelectric impedance, measurement of total body potassium and imaging techniques like CT, ultrasound or MRI scan.
Regional fat distribution Apart from BMI, there are other factors to reckon within the domain of obesity. The patterning of adipose tissue distribution, independent of total body fat alters the health risk of obesity, e.g. increased abdominal fat defined as waist to hip ratio greater than 0.9 in men and 0.8 in women, carries an even higher and independent risk for type II diabetes, hypertension, stroke and heart disease, plus an increased overall mortality rate [10, II J. This is because excess fat in the abdominal area (central or android type obesity) is more active metabolically than fat located in the hips and thighs (peripheral or gynoid type obesity) and thus more capable of entering into processes related to heart disease.
Treatment Who should lose weight? Doctors generally agree that people who are 20% or more overweight, especially the severely obese persons, can gain significant health benefits from weight loss. Many obesity experts believe that people who are less than 20% above their healthy weight should try to lose weight if they have any of the following risk factors: (a) Family history of heart disease or diabetes.
62
(b) Pte-existing medical conditions - like high blood pressure, high cholesterol levels or high blood sugar levels. (c) "Apple" shape i.e. central or android type of obesity. Treatment of obesity often entails frustration for both physician and patient because of the great difficulty in maintaining weight loss over the long term. Regardless of the weight loss method used, there is a strong tendency to regain weight. Most people regain as much as two thirds of their lost weight by one year post treatment and almost all of the weight by 5 years [10]. Following weight loss, the major structural change in adipose cellularity is shrinkage in fat cell size with no change in cell number. This suggests that formerly obese persons are not really "cured" of their obesity, at least in terms of the total number of fat cells present. It is because of this that formerly obese patients have an extremely difficult time maintaining their new body size. Also, it appears that when obese people lose body mass the fat cells increase their level of lipoprotein lipase, the enzyme that facilitates fat synthesis and storage. The effect of these high enzyme levels is to make it easier for formerly obese to regain fat. Clinical examination should aim at identifying previously undiagnosed chronic illnesses or co-morbidities of obesity. Laboratory testing for secondary causes of obesity like hypothyroidism is based on physician's judgement in each individual case. (a) Setting a goal - establishing a reasonable weight loss goal is critical. The "goal weight" may have nothing to do with "ideal weight". The goal should be defined ultimately by what is realistic and effective in reducing the health risks or complications associated with obesity. (b) Criteria for success - must include not only pounds lost but other objective and subjective measures of improved well being, such as lower blood pressure, an improved lipid profile, better blood glucose control, less back pain, more energy or greater mobility. Establish medical goals for weight loss and tie success to these end points. (c) Patient education - patients may feel that their obesity is the result of character flaws such as gluttony or laziness. Patients need to be educated about the etiology of obesity and explained that development of obesity is a result of complex genetic and environmental factors. By correcting his misconceptions in a scientific and non-judgemental fashion, the practitioner can minimise the guilt and self-defeating thoughts
Yadav
that often block success.
Treatment options Like treatment for hypertension or diabetes, treatment for obesity requires life long therapy. The most effective weight loss programs combine diet, nutrition, education, exercise, behaviour modification and social support. Diet/Nutrition education First step towards planning a diet most appropriate for weight loss is to keep food records and become aware of what, when and how much they eat. Second step is to know how many calories per day are appropriate to eat. To roughly estimate caloric needs for weight maintenance, multiply the desired weight by 12-15 caVlb for moderate activity; 15-20 cal/lb for higher levels of activity. The actual requirement will vary depending upon individual metabolic differences. Third step is to determine the number of calories appropriate for weight reduction by subtracting 300 to 1000 caVd. Divide the number into three and you will have a calorie target for each meal. It is also important to recommend a low fat diet in the treatment of obesity. instead of focusing solely on control of total calories. However, at times more radical measures such as LCDs comprising 800-1000 kcaVd or very low calorie diets (VLCDs) comprising 400-600 kcaVd need to be adopted. Exercise and lifestyle activity The possibility of a genetically low resting metabolic rate increases the importance of exercise to raise use and offset the factors encouraging weight regain. Enhanced physical activity can play an important role in helping overweight patients both lose and manage their weight. Longitudinal and cross sectional studies have consistently reported that physical activity is inversely related to weight [12]. Simply having patients increase their level of exercise without restricting calorie intake is a relatively ineffective way to lose weight. When combined with a healthy diet, increased aerobic and strength training may result in optimal changes in body composition by contributing to a negative energy balance and preserving lean body mass [13]. Effects of enhanced physical activity, other than on body composition, include a reduction in blood pressure, increased sensitivity to insulin, improved lipoprotein profile and an increase in physical fitness [14]. However, so far there is little or no evidence that exercise programs can affect abdominal or visceral fat content [15]. Exercise will benefit patients even if they do not MJAFI, VOl.. $8. NO. I, 2002
Obesity
lose weight. Various studies have shown that an unfit lean man has double risk of all cause mortality when compared with a fit lean man. Unfit lean man also has a higher risk of all cause and cardiovascular disease mortality than did man who was fit and obese [16]. In addition patients who exercise regularly are likely to be less depressed, have higher self esteem and have an improved body image. Any activity aimed at weight reduction must involve large muscle groups to induce large energy expenditure. Examples include walking, cycling, swimming, dancing, cross country skiing, skating, basketball and soccer [14]. Barriers to Activity
Inspite of many patients recognizing that regular exercise is important from both health and weight management perspectives, very few of them participate in regular exercise programs [17]. A survey of overweight sedentary patients has shown four greatest barriers to regular activity :- Lack of time - Embarrassment at taking part in activity. - Inability to exercise vigorously - Lack of enjoyment of exercise. A lack of time has consistently been reported as the greatest obstacle to being active. In this background, new strategies to promote physical activity are being explored that stray from the classic exercise prescription of at least 30 minutes of uninterrupted vigorous activity done 3 or more days per week. The American College of Sports Medicine (ACSM) and the Centre for Disease Control and prevention have recommended that all patients should attempt to accumulate 30 minutes or more of moderate intensity physical activity on most or preferably all days [18]. The aim is to offer a greater range of choices for sedentary people, especially those who do not enjoy traditional activity. Three 10 minute bouts of aerobic exercise yield fitness improvements comparable to, though slightly less than, those from one continuous 30 minute session [13,19]. Moreover, the strategy of splitting up the workouts may result in better exercise adherence and increased weight loss [20]. The concept of "lifestyle activity" encourages patients to look for opportunities everyday to increase energy expenditure. A few examples for increasing daily energy expenditure are :- Parking the car at the far end of the parking lot. - Gardening, raking leaves, and mowing the lawn. - Housework such as cleaning, vacuuming. dusting MJAFI. VOL 58. NO. 1.2002
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and dish washing. - Using stairs and walking whenever possible rather than using elevators, escalators and moving walks. - Walking during lunch breaks. - Using fewer labour saving devices such as remote controls. - Playing with or baby-sitting toddlers. Focusing on lifestyle activity may be a suitable initial exercise program for an obese patient who finds it difficult to comply with a vigorous exercise regimen or for those who do not have time for a traditional exercise program or those who do not enjoy exercise [13]. The exercise prescription for the obese individual who is ready to start a traditional exercise program should involve not only cardio-respiratory fitness enhancement, but also strength training, lifestyle activity and flexibility exercises. ACSM recommends aerobic exercise 20 to 60 minutes (which can be broken into 10 minute bouts) 3 to 5 days per week, resistance training 2 to 3 days per week, and flexibility training 2 to 3 days per week [13,21]. Behaviour modification Behaviour modification techniques are also important and helpful adjuncts and include: - Stimulus control - e.g. keeping food out of sight, eating only at specific times and places, and layout your exercise clothes to remind you to do physical activity. - Eating management - e.g. eating slowly. - Behaviour substitution - e.g. when angry or feeling dull, exercising instead of sitting at home and eating. - Self monitoring - using food and exercise diaries. - Rewards - reward yourself for changes such as reducing grams of fat or increasing minutes of exercise. - Stress management - reduce or cope with stress by exercising regularly, meditating, or learning relaxation techniques. - Cognitive-behavioral strategies - e.g. identify your unrealistic expectations and focus on changing your attitudes and beliefs. Talk about yourself positively, imagine yourself eating well and exercising regularly. - Social support - use family and friends as a source of support for encouragement and positive reinforcement of your goals. Pharmacological treatment of Obesity Drug therapy is recommended as a treatment for
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persons with (A) BMI greater than or equal to 30 with no obesity related conditions or (B) BMI of equal to or greater than 27 with two or more obesity related conditions. Anti-obesity drugs are designed to be part of comprehensive weight-loss program that includes regular exercise and a low-fat, low calorie diet. Currently the three weight loss drugs, approved by the US Food and Drug Administration (FDA) for treating obesity, areOrlistat - Approved by the FDA in April 1999,orlistat is the first drug in a new class of anti-obesity drugs that works by blocking the body's absorption of dietary fat. Orlistat works in the gastrointestinal tract, blocking the digestive enzyme pancreatic lipase, reducing absorption of fat by the intestine. Phentermine - an appetite suppressant, has been available for many years. It is half of the "fen-phen" combination (Fenfluramine or Dexfenfluramine plus Phentermine) that remains available for use. It increases availability of brain chemical norepinephrine, inhibits appetite. The use of phentermine alone has not been associated with adverse health effects of the fenfluramine-phentermine combination. Sibutramine - (Sibutramine hydrochloride monohydrate) represents the fist in a new class of anti-obesity drugs known as "neurotransmitter uptake inhibitors." It increases availability of brain chemicals norepinephrine and serotonin and inhibits appetite. Sibutramine is the only appetite suppressant medication approved for longer-term use in significantly obese patients, although the safety and effectiveness have not been established for use beyond one year. The two popular appetite suppressants, fenfluramine and Dex fenfluramine were removed from the market in Sep 1997 after studies strongly suggested that they could damage the heart's mitral valve [22,23]. Weight loss drugs on the horizon
Leptin - This brain chemical (neuropeptide) works by suppressing appetite. Cholecystokinin boosters - Cholecystokinin is a brain chemical believed to produce the feeling of fullness.
Surgical treatment Surgery is recommended for weight loss in certain severely obese patients who haven't responded to less invasive treatments. People with a BMI over 40 or people with BMI over 35 with medical complications are considered candidates for surgery. Surgical proce-
dures to help control obesity generally are divided into two categories: (1) restrictive (2) combined restrictive and malabsorptive. Restrictive Surgery - uses bands or staples to create food intake restsriction. There are two operative procedures in this - Vertical Banded Gastroplasty and Gastric Banding. Combined Restrictive and Malabsorptive Surgery is a combination of restrictive surgery (stomach pouch) with bypass or malabsorptive surgery, in which the stomach is connected to the jejunum or ileum of the small intestine, bypassing the duodenum. There are two operative procedures in this -Roux-en- Y Gastric Bypass and Biliopancreatic Diversion [24]. Other Procedures - Other procedures for weight loss, which are usually not recommended, include jaw wiring and liposuction. References 1. Eckel RH, Krauss RM. American Heart Association call to action : Obesity as a major risk factor for coronary heart disease. AHA Nutrition committee. Circulation 1998; 97(21): 2099-100. 2. Bray GA. Health hazards of obesity. Endocrinology and Metabolism Clinics of North America 1996;25:907-19. 3. Charles SO, Blumberg P. Assessment of psychiatric status among morbidity obese. Obs Bariatr Med 1982;11:71-8. 4. Anderson RE, Blair SN. Cheksin U. Encouraging patients to become more physically active: the physician's role. Ann Intern Med 1997;121(5):395-400. 5. William D McArdle. Frank I. Katch. Victor L Katch. Obesity and weight control : Exercise Physiology. 3rded. Malvern. Lea and Febiger 1991;656-97. 6. Bouchard C. Genetic factors in obesity. Med Clin North Am 1989;73(1 )61-81. 7. Behme MT. Leptin:produet of the obese gene. Nutr Today 1996;31(4): 138-41. 8. Considine RV. Sinha MK, Heiman ML. Serum immunoreactive-Ieptin concentrations in normal weight and obese humans. N Engl J Med 1996;334(5):292-5. 9. Ravussin E, Swinburn B. Energy metabolism. In:Stunkard nded. AJ. Wadden TA, editors. Obesity:Theory and Therapy, 2 New York City: Raven Press, 1993;97-124. 10. Speer SJ, Speer AJ. Office-based treatment of adult obesity. The Physician and Sports medicine 1997;25(4):94-107. 11. Kissebah AH, Freedman OS. Peiris AN. Health risks of obesity. Med Clin North Am 1989;73(1):111-38. 12. Grilo CM, Brownell KD. Stunkard AJ. The metabolic and physiologic importance of exercise in weight control. In:Stunkard AJ, Wadden TA, editors. Obesity:Theory and nded. Therapy, 2 New York City:Raven Press, 1993;253-73. 13. Rose E Anderson. Exercise, an active lifestyle. and obesity:making the exercise prescription work. The Physician and Sports Medicine. 1999;27( 10):41-50. 14. Oded Bar-Or. Juvenile obesity, physical activity and lifestyle MJAFI. VOL 58, NO. 1.20(}2
Obesity changes: cornerstones for prevention and management The Physician and Sports Medicine 2000;28( II ):51-8. 15. Treuth MS. Hunter GR. Figueroa-Colon R. Effects of strength training on intra-abdominal adipose tissue in obese prepubertal girls. Med Sci Sports Exerc 1998:30(12)1738-43. 16. Lee CD. Blair SN, Jackson AS. Cardio respiratory fitness. body composition and all cause and cardiovascular disease mortality in men. Am J Clin Nutr 1999:69(3):373-80. 17. Rose E Anderson. What can physicians do about obesity? The Physician and Sports medicine 2000;28(10):15-6. 18. Pate RR. Pratt M, Blair SN. 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(5):402-07. 19. Andersen RE. Waden TA. Bartlett SJ. Effects of lifestyle activity vs structured aerobic exercise in obese women : a randomized trial. JAMA 1999:281(4):335-40.
6S 20. Jakicic JM, Winters C, Lang W. Effects of intermittent exercise and use of home exercise equipment on adherence. weight loss. and fitness in overweight women: a randomized trial. JAMA 1999:282(16): 1554-60. 21. Pollock ML. Gaesser GA. Butcher JD. The recommended quantity and quality of exercise for developing and maintaining cardio respiratory and muscular fitness and flexibility in healthy adults. Med Sci Sports Exerc 1998;30(6):975-91. 22. Connolloy HM. Grary JL, MC Goon MD. Valvular heart disease associated with fenfluramine-phentermine. N Eng J Med 1997;337:581-8. 23. Abenhaim L, Moride Y. Brenot F. Appetite suppressant drugs and the risk of primary pulmonary hypertension. N Eng J Med 1996;1121:609-16. 24. Karl JG. Surgical treatment of obesity. Med Clin North Am 1989;73 :251-64.
