Overweight and Obesity: A Global Problem requires Practical Tools

Karen Donato, USA.
Overweight and obesity are escalating on almost every continent but the prevalence varies markedly among regions and nations. According to the WHO Consultation on Obesity, despite the limited availability of nationally representative data, evidence suggests that the prevalence of overweight and obesity is increasing worldwide at an alarming rate in both developing and developed countries. In many developing countries, obesity coexists with undernutrition 1. In the United States, recent statistics from the National Health and Nutrition Examination Survey (NHANES) show that between 1994 and 1999, the number of adults who are overweight or obese increased by 5 percent to 61 percent 2. Almost 108 million adults are either overweight or obese and because of their weight, are at greater risk for several major diseases, including coronary heart disease, hypertension, stroke, diabetes, and cancer.

How Are Overweight and Obesity Measured and Defined?
Although the terms overweight and obesity are often used interchangeably, overweight refers to an excess of body weight compared with height, while obesity refers to an excess of body fat. In populations with high levels of adiposity, excess body fat or adiposity is highly correlated with body weight. Thus, the body mass index, or BMI, which is calculated by dividing weight in kilograms by height in meters squared, is a valid and convenient measure of adiposity. Additional information from NHANES III shows that the prevalence of high blood pressure and mean levels of systolic and diastolic blood pressure increases as BMI increases. The trend of higher prevalence of high blood pressure with increasing BMI is similar for white, black and Mexican-American men and women, but the age-adjusted rates are highest among blacks at every BMI level 3.

The Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults: Evidence Report 4released by the National Heart, Lung, and Blood Institute in June 1998 defined overweight as a BMI of 25-29.9 kg/m 2and obesity as a BMI of 3 30 kg/m 2. The guidelines are based on the most extensive review conducted to date of the scientific evidence on overweight and obesity. The review was undertaken by a 24-member Expert Panel, which sought to answer 35 key clinical questions on how different treatment strategies affect weight loss, and how weight control affects the major risk factors for heart disease and stroke, as well as other chronic diseases and conditions. The resulting Guidelines present a new approach for the assessment, classification, and treatment of overweight and obesity while establishing principles of safe and effective weight loss.

What Are the Clinical Guidelines For the Assessment and Treatment of Overweight and Obese Patients?
According to the Clinical Guidelines Evidence Report , treatment of an overweight or obese patient incorporates a two step process: assessment and management. Assessment includes determination of the degree of obesity and overall health status. Management involves not only weight loss and maintenance of body weight but also measures to control other risk factors. Obesity is a chronic disease; thus, patient and practitioner must understand that successful treatment requires a lifelong effort. Convincing evidence supports the benefit of weight loss for reducing blood pressure, lowering blood glucose, and improving dyslipidemias 4.

Assessment of a patient should include the evaluation of BMI, waist circumference, and overall medical risk. Clinical judgement must be employed when evaluating very muscular patients because BMI may overestimate the degree of fatness in these patients. Excess abdominal fat is an important, independent risk factor for disease. The evaluation of waist circumference to assess obesity or overweight is supported by research. In addition, the measurement of waist-to-hip ratio provides no advantage over waist circumference alone. Men who have waist circumferences greater than 40 inches, and women who have waist circumferences greater than 35 inches, are at higher risk because of excess abdominal fat.
Overall risk must take into account the potential presence of other risk factors. Some conditions associated with obesity place patients at a high risk for subsequent mortality; these will require aggressive modification. Other conditions associated with obesity are less lethal, but still require treatment. The decision to attempt a weight loss treatment should also assess the patient’s readiness to make the necessary lifestyle changes.

Therapy is recommended for patients with a BMI 3 30. It is also recommended for patients with a BMI between 25 and 29.9 or who have a high waist circumference, and 2 or more risk factors. Individuals at lesser risk should be counseled about effective lifestyle changes, if they are ready to change. Therapy begins with lifestyle changes in diet and physical activity. When these are not achieved after 6 months, then careful consideration can be given to pharmacotherapy in patients with a BMI 3 30 or a BMI 3 27 with additional risk factors. 4

What Are the Goals Of Therapy For Weight Loss?
The goals of therapy are to reduce body weight and maintain a lower body weight for the long term; the prevention of further weight gain is the minimum goal. An initial weight loss of 10% of body weight, achieved over six months, is a recommended target. The rate of weight loss should be 1 to 2 pounds each week. Greater rates of weight loss do not achieve better long-term results. After the first six months of weight loss therapy the priority should be weight maintenance, which is achieved through the combined changes in diet, physical activity, and behavior. In some patients, weight loss is not achievable. A goal for these patients should be the prevention of further weight gain, as this would exacerbate disease. Prevention of weight gain can be a successful goal for some of these individuals. 4

What Tools Are Available To Help Professionals Treat and Manage Overweight and Obese Patients?
Since the release of the Guidelines, the NHLBI’s Obesity Education Initiative has been striving to help health care practitioners better assess and treat overweight patients. Several practical tools have been designed to be succinct, practical references for the busy health professional and patient. One of the latest tools available is the Practical Guide to the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults 5developed by the NHLBI in cooperation with the North American Association for the Study of Obesity. It describes how health care practitioners can provide their patients with the direction and support needed to effectively lose weight and keep it off. Based on The Evidence Report , it provides health care practitioners the basic tools necessary to assess and manage overweight and obesity. It includes practical information on dietary therapy, physical activity, and behavior therapy, while also providing guidance on the appropriate use of pharmacotherapy and surgery as treatment options. An innovative feature of the guide is a tear out quick reference guide to help practitioners assess, classify, and treat (ACT) overweight and obese patients. Re-producible tip sheets for patients are included in the guide. The Practical Guide and several other resources for treating overweight and obesity are available through NHLBI and can be found on the Aim for a Healthy Weight website (http://www.nhlbi.nih.gov/health/public/heart/obesity/lose_wt/index.htm).

Many of these publications are available for professionals and the public. They can be ordered online at (http://emall.nhlbihin.net/dept2.asp?dept_id=OVERWT) or contact the NHLBI Health Information Center at phone (301) 592-8573 or email NHLBIInfo@rover.nhlbi.nih.gov.

  1. Obesity: Preventing and managing the global epidemic. Report of a WHO consultation on obesity. Geneva, June 3-5, 1997.
  2. Prevalence of overweight and obesity among adults: United States, 1999. National Center for Health Statistics Health E-Stats, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services. (http://www.cdc.gov/nchs/products/pubs/pubd/hestats/3 and 4/overweight.htm
  3. Brown C, Higgins M, Donato K, et al. Body mass index and the prevalence of hypertension and dyslipidemia. Obesity Research 2000; 8: 9, 605-619.
  4. The Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults: Evidence Report. National Heart, Lung and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services. September 1998, NIH pub. No. 98—4083.
  5. The Practical Guide: Identification, Evaluation and Treatment of Overweight and Obesity in Adults. National Heart, Lung and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services. October 2000, NIH Pub. No 00-4084.
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