Obesity is a chronic, multidimensional problem which is being increasingly seen in younger patients. Besides obesity is becoming an epidemic in industrialized countries and is continuing to increase in developing countries worldwide. And obesity is a major health epidemic that affects millions of people worldwide. To date, approximately 127 million US adults are considered to be overweight, with 60 million obese and over 9 million severely obese, accounting for an estimated 65% of the adult population. Since 1980, these numbers have increased approximately 20%, with the numbers predicted to increase dramatically within the next 20 years. Additionally, obesity is a major health concern, with an estimated 300,000 deaths per year nationwide attributed to obesity and the economic cost of dealing with obesity-related illnesses estimated at 117 billion dollars. Obesity has many serious health implications, including the risk of developing type 2 diabetes mellitus, hypertension, dyslipidemia, cancer, osteoporosis, and cardiovascular disease.
On a simple level, the culprit of obesity among the population can be the genetic factors. Although a lot of advanced researches highlighted the role of molecular genes as a dominant factor of obesity, our genes have not changes significantly during the past two decades. It may well explain the cross-sectional differences among the people with endowment heterogeneity. But, it’s not clear how it would identify the rapid change in obesity over time. Another one is an environment factor that promotes behaviors that lead to obesity. Several studies indicated that the quality of life may be compromised in obese people because of the impaired physical and psychosocial functioning. Obesity can arise when energy intake is larger than energy expenditure. Therefore, the behaviors that the environment fosters may be correlated with the obesity. According to the Report of the Surgeon General, low level of physical activity is associated with an increasing trend of obesity, and we know that our current environment is discouraging physical activities. The technological improvement and advancement of media and transportation have decreased the need for physical activities of the people.
Several methods exist to determine one’s level of body weight, with some methods of detections more accurate than others. The gold standard of measuring body fat can be determined using underwater weighing or hydrostatic weighing. This method of determining body fat uses the assumptions that density and specific gravity of lean tissue is greater than that of fat tissue. Thus lean body tissue will sink in water and fat tissue will float. Therefore, one can accurately measure body composition by comparing one’s mass measured under water to that measured out of water. Although hydrostatic weighing is a very accurate means of determining body composition, very few facilities carry the large tanks necessary for measurements. Additionally, this procedure can take up to one hour to get accurate measurements. Another form of measuring body composition is the dual-energy X-ray absorptiometry (DEXA scan) that is used to determine an individual’s bone density. This procedure uses X-rays to determine not only the percentage of body fat, but also the specific location of the body fat. However, although DEXA scans are very accurate as well, this measurement is not commonly used to assess one’s body composition due to limited access in only a few research facilities, time involved in the procedure, and the expense associated with the measurements. Computed tomography (CT scans) offer a means of distinguishing between the two primary types of body fat, visceral and subcutaneous adipose tissue. Visceral adipose tissue is centrally located and surrounds the inner abdominal organs. Subcutaneous adipose tissue is the more generalized fat tissue that is distributed throughout the entire body. Recent studies have shown that visceral adipose tissue is more detrimental to one’s health and often increases the risk of developing more serious health complications, such as type 2 diabetes and cardiovascular disease. CT scans work by producing cross-section radiographs of the abdomen that then allows for computerized measurement of total fat area, along with the distinction between total visceral and total subcutaneous fat area. CT scans can be very reliable and accurate, however is not often the usual means of determining body weight due to the need for experienced technicians needed to perform the scan, lack of CT imaging scans in many research facilities, and the expense associated with the scans. Measuring body fat has proven to be difficult and expensive if done correctly, thus several more simple and straightforward methods have been largely used to gain an estimate of body fat. The most widely accepted method of quantifying an individual’s obesity level is the body mass index (BMI). BMI is calculated from a ratio equation of height squared divided by weight. However, although BMI can be accurately used to determine one’s obesity level, it does not offer any indication of lean or fat mass, nor can it determine the actual type of fat mass present, as in the CT scan. A BMI value over 25 kg/m" is considered overweight and a BMI value over 30 kg/m2 is considered obese. Two additional common measures of obesity include waist-to-hip ratio (WHR) and waist circumference. Waist circumference is defined as the smallest circumference between the rib cage and the iliac crest and hip measurement is the largest circumference between the waist and the thighs. Standard criteria for obesity in women is a WHR greater than 0.85 and a waist greater than 88 cm. In men, obesity indexes for WHR consist of values greater than 1.0 and a waist circumference greater than 102 cm. Both waist and WHR can be used as surrogate measures for central obesity when more sophisticated measures such as the CT scan are inaccessible.
So obesity is no longer considered a single disease. Then the treatment of obesity is urgent. And the key of the methods is based on the balance of caloric intake and energy expenditure. The treatment tools contain:
1. Dietary Modification. Reducing calories and practicing healthier eating habits are vital to overcoming obesity.
2. Exercise and Activities. More physical activities or exercise is an essential part of controling weight.
3. Behavior Modification. This way is change eating and exercise habits to promote weight loss. Inclduing setting realistic weight loss goals,recording diet and exercise daily patterns and so on.
4. Medications. Anti-obesity medicines might be suitable for people whose BMI of 30 or greater. But the anti-obesity medication must be used along with diet, exercise and behavior changes, not instead of them. If not, medication is unlikely to work. Now sibutramine, orlistant and lorcaserin hydrochloride are approved by the Food and Drug Administration (FDA) to treat obesity. Besides the combination of two medicines is an option, like phentermine/topiramate, naltrexone/bupropion and exenatide/liraglutide.
5. Weight-loss surgery. This might be an choice for people who have extreme obesity when the BMI is over 40 and other trearments have failed.
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