Obesity

What is Obesity?

Obesity is an abnormal accumulation of body fat, usually 20% or more over an individual’s ideal body weight. Obesity is associated with increased risk of illness, disability, and death.

The branch of medicine that deals with the study and treatment of obesity is known as bariatrics. As obesity has become a major health problem in the United States, bariatrics has become a separate medical and surgical specialty.

Description of Obesity

Obesity traditionally has been defined as a weight at least 20% above the weight corresponding to the lowest death rate for individuals of a specific height, gender, and age (ideal weight). Twenty to forty percent over ideal weight is considered mildly obese; 40–100% over ideal weight is considered moderately obese; and 100% over ideal weight is considered severely, or morbidly, obese. More recent guidelines for obesity use a measurement called BMI (body mass index) which is the individual’s weight multiplied by 703 and then divided by twice the height in inches. BMI of 25.9–29 is considered overweight; BMI over 30 is considered obese. Measurements and comparisons of waist and hip circumference can also provide some information regarding risk factors associated with weight. The higher the ratio, the greater the chance for weight-associated complications. Calipers can be used to measure skin-fold thickness to determine whether tissue is muscle (lean) or adipose tissue (fat).

Much concern has been generated about the increasing incidence of obesity among Americans. Some studies have noted an increase from 12% to 18% occurring between 1991 and 1998. Other studies have actually estimated that a full 50% of all Americans are overweight. The World Health Organization terms obesity a worldwide epidemic, and the diseases which can occur due to obesity are becoming increasingly prevalent.

Excessive weight can result in many serious, potentially life-threatening health problems, including hypertension, Type II diabetes mellitus (non-insulin dependent diabetes), increased risk for coronary disease, increased unexplained heart attack, hyperlipide-mia, infertility, and a higher prevalence of colon, prostate, endometrial, and, possibly, breast cancer. Approximately 300,000 deaths a year are attributed to obesity, prompting leaders in public health, such as former Surgeon General C. Everett Koop, M.D., to label obesity ‘‘the second leading cause of preventable deaths in the United States.’’

               
 Height and weight goals

                                Men     

Height   Small frame        Medium frame          Large frame

5'2'         128-134 lbs.        131-141 lbs.        138-150 lbs.

5'3'         130-136                133-143                140-153

5'4'         132-138                135-145                142-153

5'5'         134-140                137-148                144-160

5'6'         136-142                139-151                146-164

5'7'         138-145                142-154                149-168

5'8'         140-148                145-157                152-172

5'9'         142-151                148-160                155-176

5'10”      144-154                151-163                158-180

5'11”      146-157                154-166                161-184

6'O'        149-160                157-170                164-188

6'1'         152-164                160-174                168-192

6'2'         155-168                164-178                172-197

6'3'         158-172                167-182                176-202

6'4'         162-176                171-187                181-207

                             

                                   Women               

Height   Small frame        Medium frame        Large frame

4'10'       102-111 lbs.        109-121 lbs.        113-131 lbs.

4'11'       103-113                111-123                120-134

5'0”        104-115                113-126                112-137

5'1”        106-118                115-129                125-140

5'2”        108-121                118-132                128-143

5'3”        111-124                121-135                131-147

5'4”        114-127                124-141                137-151

5'5”        117-130                127-141                137-155

5'6”        120-133                130-144                140-159

5'7”        123-136                133-147                143-183

5'8”        126-139                136-150                146-167

5'9”        129-142                139-153                149-170

5'10”      132-145                142-156                152-176

5'11”      135-148                145-159                155-176

6'0”        138-151                143-162                158-179

What are the causes and symptoms of Obesity?

The mechanism for excessive weight gain is clear—more calories are consumed than the body burns, and the excess calories are stored as fat (adipose) tissue. However, the exact cause is not as clear and likely arises from a complex combination of factors. Genetic factors significantly influence how the body regulates the appetite and the rate at which it turns food into energy (metabolic rate). Studies of adoptees confirm this relationship—the majority of adoptees followed a pattern of weight gain that more closely resembled that of their birth parents than their adoptive parents. A genetic predisposition to weight gain, however, does not automatically mean that a person will be obese. Eating habits and patterns of physical activity also play a significant role in the amount of weight a person gains. Recent studies have indicated that the amount of fat in a person’s diet may have a greater impact on weight than the number of calories it contains. Carbohydrates like cereals, breads, fruits, and vegetables and protein (fish, lean meat, turkey breast, skim milk) are converted to fuel almost as soon as they are consumed.

Most fat calories are immediately stored in fat cells, which add to the body’s weight and girth as they expand and multiply. A sedentary lifestyle, particularly prevalent in affluent societies, such as in the United States, can contribute to weight gain. Psychological factors, such as depression and low self-esteem may, in some cases, also play a role in weight gain.

At what stage of life a person becomes obese can affect his or her ability to lose weight. In childhood, excess calories are converted into new fat cells (hyper-plastic obesity), while excess calories consumed in adulthood only serve to expand existing fat cells (hypertrophic obesity). Since dieting and exercise can only reduce the size of fat cells, not eliminate them, persons who were obese as children can have great

difficulty losing weight, since they may have up to five times as many fat cells as someone who became overweight as an adult.

Obesity can also be a side effect of certain disorders and conditions, including:

Cushing’s syndrome, a disorder involving the excessive release of the hormone cortisol

hypothyroidism, a condition caused by an underactive thyroid gland

neurologic disturbances, such as damage to the hypothalamus, a structure located deep within the brain that helps regulate appetite

consumption of such drugs as steroids, antipsychotic medications, or antidepressants

The major symptoms of obesity are excessive weight gain and the presence of large amounts of fatty tissue. Obesity can also give rise to several secondary conditions, including:

arthritis and other orthopedic problems, such as lower back pain

hernias

heartburn

adult-onset asthma

gum disease

high cholesterol levels

gallstones

high blood pressure

menstrual irregularities or cessation of menstruation (amenorhhea)

decreased fertility, and pregnancy complications

shortness of breath that can be incapacitating

sleep apnea and sleeping disorders

skin disorders arising from the bacterial breakdown of sweat and cellular material in thick folds of skin or from increased friction between folds

emotional and social problems

How is Obesity diagnosed?

Diagnosis of obesity is made by observation and by comparing the patient’s weight to ideal weight charts. Many doctors and obesity researchers refer to the body mass index (BMI), which uses a height-weight relationship to calculate an individual’s ideal weight and personal risk of developing obesity-related health problems. Physicians may also obtain direct measurements of an individual’s body fat content by using calipers to measure skin-fold thickness at the back of the upper arm and other sites. The most accurate means of measuring body fat content involves immersing a person in water and measuring relative displacement; however, this method is very impractical and is usually only used in scientific studies requiring very specific assessments. Women whose body fat exceeds 30% and men whose body fat exceeds 25% are generally considered obese.

Doctors may also note how a person carries excess weight on his or her body. Studies have shown that this factor may indicate whether or not an individual has a predisposition to develop certain diseases or conditions that may accompany obesity. ‘‘Apple-shaped’’ individuals who store most of their weight around the waist and abdomen are at greater risk for cancer, heart disease, stroke, and diabetes than ‘‘pear-shaped’’ people whose extra pounds settle primarily in their hips and thighs.

What is the treatment for Obesity?

As many as 85% of dieters who do not exercise on a regular basis regain their lost weight within two years. In five years, the figure rises to 90%. Repeatedly losing and regaining weight (yo yo dieting) encourages the body to store fat and may increase a patient’s risk of developing heart disease. The primary factor in achieving and maintaining weight loss is a life-long commitment to regular exercise and sensible eating habits.

How can you prevent Obesity?

Obesity experts suggest that a key to preventing excess weight gain is monitoring fat consumption rather than counting calories, and the National Cholesterol Education Program maintains that only 30% of calories should be derived from fat. Only one-third of those calories should be contained in saturated fats (the kind of fat found in high concentrations in meat, poultry, and dairy products). Because most people eat more than they think they do, keeping a detailed food diary is a useful way to assess eating habits. Eating three balanced, moderate-portion meals a day—with the main meal at mid-day—is a more effective way to prevent obesity than fasting or crash diets. Exercise increases the metabolic rate by creating muscle, which burns more calories than fat. When regular exercise is combined with regular, healthful meals, calories continue to burn at an accelerated rate for several hours. Finally, encouraging healthful habits in children is a key to preventing childhood obesity and the health problems that follow in adulthood.

KEY TERMS

Adipose tissue = Fat tissue.

Appetite suppressant = Drug that decreases feelings of hunger. Most work by increasing levels of serotonin or catecholamine, chemicals in the brain that control appetite.

Bariatrics = The branch of medicine that deals with the prevention and treatment of obesity and related disorders.

Ghrelin = A recently discovered peptide hormone secreted by cells in the lining of the stomach. Ghre-lin is important in appetite regulation and maintaining the body’s energy balance.

Hyperlipidemia = Abnormally high levels of lipids in blood plasma.

Hyperplastic obesity = Excessive weight gain in childhood, characterized by the creation of new fat cells.

Hypertension = High blood pressure.

Hypertrophic obesity = Excessive weight gain in adulthood, characterized by expansion of already existing fat cells.

Ideal weight = Weight corresponding to the lowest death rate for individuals of a specific height, gender, and age.

Leptin = A protein hormone that affects feeding behavior and hunger in humans. At present it is thought that obesity in humans may result in part from insensitivity to leptin.

From Gale Encyclopedia of diets