Over the years, healthcare providers and consumers have had trouble defining who is fat, overweight or obese. To make matters worse, some people remain confused about these terms, and still use them interchangeably. In an effort to clarify these terminologies and provide scientific guidelines for the medical management of individuals with excess weight, in 1998, the National Heart, Lung and Blood Institute (NHLBI), in collaboration with the National Institute of Diabetes, Digestive and Kidney Disease (NIDDK), established the first Federal guidelines on the identification, evaluation and treatment of overweight and obesity in adults. These clinical practice guidelines are designed to help healthcare providers in their care of the obese and overweight. These two public health problems are believed to affect about 100 million American adults, a figure that translates into approximately one out of every three Americans!
From these guidelines, being overweight, and obesity are defined using a new parameter called the Body Mass Index (BMI). The body mass index describes one's body weight relative to height, and is believed to strongly correlate with the total body fat content in adults, hence the emphasis on this parameter. Adding more weight to the significance of BMI, is the recent finding that, as an independent marker, it correlates with risk of death and illness in a given individual. How do you know if you are overweight or obese?
It is very easy to find out using the new guidelines. First, you measure your weight in kilograms (note that 2.2Ibs equals 1kg). Then obtain your height in meters (1 inch equals 0.0254 meters). Calculating your BMI involves dividing your weight in kg by the square of your height in meters. It is mathematically expressed as follows;
BMI=weight in kilograms/height in meters x height in meters.
Really, you do not need to know this formula to figure your BMI. There are numerous programs and charts that can match your weight and height and come up with the same information.
Using the recommended guidelines, the following definitions have emerged;
A person with a BMI of 25-29.9 is considered overweight
A person with a BMI of 30 and above is obese
The cut-off point, a BMI of 25, represents the threshold beyond which excess weight gain begins to pose significant risk to an individual's health. In fact, there is solid evidence to suggest that the risk of cardiovascular (heart and blood vessel) disorders and other diseases to be discussed later in this article rises significantly when someone's BMI exceeds 25. Therefore, the new guidelines also call for periodic check of BMI in all adults during their routine physical examinations. Individuals with normal weight are encouraged to have their BMI reassessed every two years.
Medical problems associated with obesity
There is indeed a long list of medical conditions associated with obesity. For some of these conditions, the evidence linking them to obesity is overwhelming. As for other diseases where the evidence may not be as strong, clinicians have long known that weight reduction frequently improves the outcome for patients. With this in mind, maintaining one's ideal body weight should be considered a life-long pursuit, since you almost always have nothing to lose, in the immediate or long term, and a lot to gain. It is important to note that for the following medical conditions, the higher the BMI, the greater the risks.
- Type 2 Diabetes (formerly called adult onset diabetes) - It is believed that with increasing weight gain, particularly when the BMI exceeds 27, the body's ability to respond to the hormone, insulin, is compromised. When this happens, the glucose obtained from the food we have eaten remains in the blood stream, unavailable for the body's cells, and diabetes results.
- Hypertension - With increasing weight, the heart has to work harder to get blood circulating all over the body, and this added strain can lead to high blood pressure. In addition, the clogging of blood vessels from associated cholesterol disorders impedes blood flow, resulting in elevated blood pressure, independent of the excess weight gain.
- Cholesterol disorders and blood clots
- Heart Attacks and Angina - primarily due to the reasons alluded to above.
- Stroke (brain attack) - results from greater prevalence of high blood pressure and clogged arteries in these individuals.
- Gallbladder disease - because of increased risk of gallstones.
- Obstructive Sleep Apnea - a medical condition in which affected individuals stop breathing briefly and repeatedly during sleep. This usually manifests as loud snoring, morning headache, tiredness, poor concentration at work, and daytime excessive sleepiness. Although also present in non-obese individuals, it is more common in the overweight population, particularly those with a neck size greater than 17.
- Breathing problems other than sleep apnea
- Certain cancers such as colon cancer - are believed to be more common in obese individuals.
- Arthritis (Joint problems) - particularly the weight bearing joints such as the knees, hips and spine.
Keeping the body mass index less than 25
According to the new guidelines, to attain and maintain a BMI less than 25 will require a multi-pronged approach, depending on the individual's baseline BMI. Basically, the accepted treatment and preventive strategies for individuals who are overweight or obese are all aimed at losing weight in a controlled fashion. The initial goal of treatment should be to reduce body weight by about 10 percent from baseline, an amount that is believed to reduce obesity related risks. Subsequently, further weight loss can be attempted - the goal being to attain ideal BMI (20 - 24). The suggested safe duration of time to achieve this 10 percent reduction from baseline weight is six months. If appropriate, further weight loss should be one to two pounds per week. The strategy to achieve the weight loss will, of course, depend on the patient's baseline weight and other co-existing medical conditions. Recommended strategies for weight loss include:
Calorie reduction - individuals need to be aware that reducing dietary fat alone, without cutting down on overall calorie intake will not lead to weight loss. Consultation with nutrition experts will be prudent.
Increased physical activity - individuals cleared by their physicians to engage in vigorous exercise, should engage in moderate physical activity, for at least 30 minutes a day, and no less than 4 times a week. For those with type 2 diabetes, exercise is an important adjunct to medication in the control of their disease. In fact, for individuals with a family history of type 2 diabetes who have not yet developed the disease, regular exercise is the most important 'prescription' to prevent or delay the onset of diabetes.
Medications - the key thing to remember here is do not take any medications (over the counter ones) included, without physician supervision. It is equally dangerous to use a friend's or a relative's weight loss drugs without obtaining your physician's approval. We are all now familiar with Fen-Phen (the wonder drug for weight loss) and the damage it causes to the heart. It is also recommended that drug therapy should only be considered if lifestyle changes suggested above have been tried for at least six months without appreciable success. The risks of adverse effects from the drugs should be balanced against the intended benefits. Bearing this in mind, drug therapy will be worth the risks in patients with BMI greater than 30 without the additional risk factors or medical conditions noted earlier, or BMI of 27 or greater with two or more of those conditions. If drug therapy is considered an option, use only the weight loss drugs approved by the Food and Drug Administration (FDA). Usually, these drugs are not to be used for more than one year.
Weight loss surgery - This most commonly refers to stomach stapling which is used to reduce the volume of the stomach, thus allowing satiety to be reached early. This should be considered an option for carefully screened individuals with severe obesity - defined as BMI of 40 or greater or BMI of greater than 35 with co-existing conditions when other measures outlined above have failed and the patient is at significant risk for obesity-associated illness.
It must be mentioned that of all the weight losing modalities noted above, calorie reduction and increased physical activity have the best efficacy and safety profile. A health club membership is safer and more cost effective in the long run than medications or surgery. Also, unlike diet and exercise, neither surgery nor medication can keep the weight off over the long term.
For more information on obesity, visit http://www.nhlbi.nih.gov/health/public/heart/obesity/lose_wt/index.htm