400 million obese people worldwide and growing. In recent decades, the consequences of obesity have drastically shifted from a social and cosmetic issue to a serious epidemiological and clinical concern. The World Health Organization (WHO) estimates that there are at least 400 million obese people worldwide with nearly 20% of the worlds obese residing in the United States. If present trends continue, by 2015 this population could exceed 700 million people globally.
76 million obese people in the US, or one in three adult Americans. Within the United States, the last 30 years brought a dramatic increase in the obese population. In 1980 a National health and Nutrition Examination Survey (NHANES) estimated that 14% of US adults were obese. As of 2004, nearly one in three adult Americans suffered from obesity, with two in three adult Americans being categorized as wither overweight or obese.
The children are our future – and it is NOT pretty. The trends become even more frightening when we see the prevalence of overweight children rising to 17% in 2004 from 5% in 1980. Larger, fattier meals combined with a more sedentary lifestyle are poised to produce damaging and potentially deadly effects. Those who are overweight an obese carry higher risks for serious co-morbidities such as type 2 diabetes, heart disease, stroke, physiological changes that predispose adults to become obese.
Obesity will have a significant burden on our healthcare system. With the numerous complications associated with weight gain, these numbers highlight the colossal burden that will be placed on healthcare systems of all developed and developing countries, unless action is taken. The direct and indirect annual cost of obesity to the system in the US is already in excess of $200 billion.
Defining the obese patient
The most common formula used in classifying a person as obese or overweight is the Body Mass Index (BMI), which is weight/height2 (kg/m2). The clinical guidelines are as follows:
- Underweight: BMI < 18.5
- Normal: BMI between 18.5 – 24.9
- Overweight: BMI between 25.0 – 29.9
- Obesity, Class 1: BMI between 30.0 – 34.9
- Obesity, Class 2 or Clinically Obese: BMI between 35.0 – 39.9
- Obesity, Class 3 or Morbidly Obese: BMI between > 40
- Obesity, Class 4 or Super Obese: BMI > 50
Once patients have been defined by a clinical classification of obesity, they can be given more appropriate care depending upon the severity of the condition. Also, with all of the complications stemming from weigh gain, the four different classes of obesity (obese, clinically obese, morbidly obese, and super obese) provide healthcare professionals with a more specific treatment algorithm to address the varying risks for developing co-morbidities.
Benchmarking patient progress
BMI is not perfect, but it is the best yardstick we have. While BMI has proven to be the best way to classify patients, it still has some flaws because it does not directly measure fat. What this means is that a person could be a lean 6’2 couch potato of the same weight.
Success is measured differently for devices and drugs. In order for researchers and patients to effectively compare results of different fat reduction therapies, there are a couple of metrics used for comparison:
- Percentage excess weight loss (%EWL) reduction has become a common benchmark for surgical procedures and medical devices. The calculation is (weight loss) / (excess weight) X 100. Excess weight is defined as the difference between the actual weight and the “ideal weight”, based on an individual’s height and the weight that they would need to have in order to yield a BMI of 25. For example, a 6’ person weighing 300lbs would have a BMI of 41 (Morbidly Obese) and be carrying approximately an extra 115lbs. Weight loss of 60 pounds would result in a %EWL of 52% (60/115).
- Percentage weight loss is a metric more used by diet, exercise, and drug therapies. It is calculated by (weight loss) / (original weight) X 100. Alternatively, a 6’ person weighing 300lbs and losing 60lbs would be reported as 20% weight loss.