According to the Merriam-Webster dictionary, obesity is a condition characterized by the excessive accumulation and storage of fat in the body. The first sentence of the Stedman’s Medical Dictionary is essentially the same, an excess of subcutaneous fat in proportion to lean body mass. The word “obesity” was first used in 1611, however the relationship between excess fat and mortality were recognized thousands of years ago. The Ancient Greek physician Hippocrates is quoted to have said 2400 years ago, “Sudden death is more common in those who are naturally fat than in the lean,” which modern physicians understand to be an ancient understanding of relationship between obesity and the massive heart attacks that cause sudden cardiac death. Even the treatment for obesity has not changed greatly in the past 1800 years. The Ancient Roman physician Galen wrote about an exercise and diet regimen he prescribed for an overweight man, which involved a lot of running and calorie-poor food. That regimen is essentially identical to the modern treatment of obesity.
By itself, obesity puts stress on the skeletal, pulmonary, and cardiovascular system. Fat deposits around the chest and neck area cause a narrowing of airways and make breathing difficult. This often leads of snoring, and in worse cases, sleep apnea, which is a condition where breathing actually stops for short periods of time during sleep. Sleep apnea leads to poor sleep quality, resulting in daytime tiredness. Obesity also stresses the heart and vascular system, as the heavy mass of obesity requires considerable energy to move, which the cardiovascular system has to supply. Heavy weight also put pressure on pressure on the skeletal system, especially on back and joints, which leads to higher rates of back pain and arthritis. In addition to these problems, there are also the physiological changes that occur due to the large amounts of fats in the blood. This includes diabetes, high blood pressure, and the hardening and narrowing of blood vessels, which are all risk factors for heart attacks and strokes.
With all these health problems caused by obesity, it is terrifying that nearly 30% of all Americans are obese. This percentage is expected to expected to grow in the future.
There are many different tests that can be used to diagnose obesity, however the most researched and reliable technique is a combination of using BMI and waist circumference cutoffs.
BMI is a measurement of weight divided by the height squared. If you are using kilograms to measure weight, and meters to measure height, the equation is “weight in kilograms divided by height in meters multiplied against itself,” which would look like W-kg / (H-m * H-m). If you are using pounds and inches to measure BMI, the equation would look like W-lb * 703 / (H-in * H-in). There is a series of cutoffs that determine underweight, normal, overweight, and obese. In white, black, and Hispanic populations, BMI values above 25 are in the overweight range, and BMI values above 30 are in the obese range. BMI values below 18.5 are considered underweight. In South and East Asian populations, BMI values over 23 are considered overweight, and BMI values over 25 are obese.
The BMI scale is considered fairly reliable, however individuals with significant amounts of muscle mass will be considered obese if this scale is used alone, so occasionally a second screening system is used in conjunction with it. Research has found that abdominal fat deposits are the most detrimental superficial deposits to health, so physicians measure the waist circumference to see if the high BMI is due to abdominal fat deposits. In white, black, and Hispanic populations with BMI value between 25 and 35, a waist circumference of above 35” in females and 40” in males is correlated to worse health. In South and East Asian populations with BMI values between 25 and 35, a waist circumference of 31” in females and 36” in males is correlated with worse health. BMI values above 35 are universally considered obese, no matter what the waist circumference is.
The basic treatment of obesity relies on a combination of reduced caloric intake and increased caloric use. In other words, limiting the amount of calories consumed, and increasing the level of physical activity so more calories are burned.
A reduced calorie diet is at the heart of weight reduction. An average American man requires roughly 2000 calories a day to maintain his weight, the average women 1800. In order to lose weight, people have to consume significantly less. Research has shown that 800 calories is the minimum daily caloric intake that results in additional weight loss, however a diet of anywhere from 800-1200 calories per day should be enough to result in some level of weight loss. This is based on the assumption that people are calculating their calories correctly; unfortunately it has been found that most people consume 10% more calories than they report, and obese people often consume 30% more. Also, while on a low calorie diet, it is important that individuals still consume sufficient quantities of the required vitamins, minerals, and other important trace nutrients. A diet without these nutrients will result in deficiency syndromes.
Increased physical activity, especially aerobic exercise, results in weight loss. Optimally, if an individual desires to exercise to lose weight, one hour of aerobic exercise 5 days a week which brings the heart rate up to at least 130 beats per minute should result in some weight reduction. However, increased exercise alone is not as effective as a low calorie diet. Exercise done in conjunction with dieting has a synergistic effect on weight reduction, and is an effective way to retain the weight reduction in the long term. Exercise also has many positive effects on the musculoskeletal and cardiovascular system.
A combination of a low calorie diet and exercise should result in about one to two pounds of weight loss a week, with a 5% weight reduction after 6 months. If a greater level of weight reduction is needed, there are several drugs that suppress appetite, increase the rate of caloric expenditure, or reduce the bodies to absorb fats, the most high calorie nutrient. If an individual is so obese that it is an immediate threat to their health and the obesity does not respond to calorie reduction or increased exercise, a physician might consider a surgical gastric operation, which essentially forces a low calorie diet. However, drugs and surgery have the possibility for adverse effects, so diet and exercise are still the mainstays of therapy.