MEASURING OBESITY

The body mass index (BMI) is commonly used to determine desirable body weights. BMI is a measure of an adult’s weight in relation to height, and it is calculated metrically as weight divided by height squared (kg/m2). People with a BMI of 25.0 to 29.9 are considered overweight and people with a BMI of 30 or above are considered obese .

Body mass index only provides a rough estimate of desirable weight, however. Physicians recognize that many other factors besides height affect weight. Weight alone may not be an indicator of fat, as in the case of a bodybuilder who may have a high BMI because of a high percentage of muscle tissue, which weighs more than fat. Likewise, a person with a sedentary lifestyle may be within a desirable weight range but have excess fat tissue. In general, however, the higher the BMI, the greater the risk for developing serious medical conditions.

CAUSES OF OBESITY

A calorie is the unit used to measure the energy value of food and the energy used by the body to maintain normal functions. When the calories from food intake equal the calories of energy the body uses, weight remains constant. But when a person consumes more calories than the body needs, the body stores those additional calories as fat, causing subsequent weight gain. Consuming about 3,500 calories more than what the body needs results in a weight gain of 0.45 kg (1 lb) of fat.

TREATMENTS FOR OBESITY

Obesity can become a chronic lifelong condition caused by overeating, physical inactivity, and even genetic makeup. No matter what the cause, however, obesity can be prevented or managed with a combination of diet, exercise, behavior modification, and in severe cases, weight-loss medications and surgery.

Diets

The most common and conservative treatment for obesity utilizes a nutritionally balanced, low calorie diet. Most health-care professionals and commercial weight-loss programs recommend diets consisting of 1,200 to 1,500 calories per day, usually in the following proportions: 60 percent carbohydrate, 30 percent fat, and 10 percent protein. Research from university obesity treatment centers indicates that patients who follow a low calorie diet lose 10 percent of their initial weight in 20 weeks. Without further treatment, however, patients usually regain one-third of the weight in the following year.

A more aggressive approach for persons who are more than 20 kg (40 lb) overweight includes very low calorie diets ranging from 400 to 800 calories per day. These diets are usually based on four to five servings of a liquid formula each day. Candidates must be carefully screened and medically supervised while on the diet. People on very low calorie diets lose approximately 15 to 20 percent of their initial body weight in 16 weeks. Once they go off a very low calorie diet, they typically regain approximately one-half of that weight within a year.

Meal replacements are liquid shakes or portion-controlled meals that are substituted for one or two meals a day. They are typically used as part of a 1,200 to 1,500 calorie diet. Studies have shown that meal replacements are often more effective than very low calories diets, resulting in an increase in the amount of initial weight loss and enabling dieters to maintain their weight loss. Unlike very low calorie diets, meal replacements do not require that candidates receive extensive medical monitoring.

Exercise

Caloric restriction alone will not produce long-term weight loss. While the data from studies on the effect of exercise for short-term weight loss are contradictory, research clearly indicates that regular exercise is the single best predictor for achieving long-term weight control. Regular exercise will also improve some of the medical conditions associated with obesity, including elevated blood cholesterol, hypertension, and diabetes mellitus.

Behavior Modification

Many eating and exercise habits combine to promote weight gain. Certain times, places, activities, and emotions may be linked to periods of overeating or inactivity. Many obesity treatment programs recommend individuals keep a food diary that records all food or drink consumed, when and with whom it was consumed, and the mood or precipitating events that trigger eating. After one to two weeks, the diary may reveal a pattern of activities or negative emotions that lead to overeating. Once these eating cues are identified, techniques can be developed and practiced to prevent unwanted eating habits.

Weight-Loss Medications

Weight-loss medications of any type are only appropriate for people with a BMI of 30 or above, or a BMI of 27 or above accompanied by weight-related medical conditions such as diabetes mellitus or hypertension. Amphetamine drugs were formerly prescribed to combat obesity, but their well-documented side effects, including insomnia, anxiety, and tolerance (the need to take higher and higher doses to continue to produce the same effect), made them less popular by the late 1970s.

A renewed scientific and commercial interest in weight-loss medications was prompted by the approval by the Food and Drug Administration (FDA) of the appetite suppressant dexfenfluramine (sold under the brand name Redux) in 1996. Dexfenfluramine was the first weight-loss medication approved in the United States in over 20 years and the first ever approved for maintaining weight loss. Although never approved for long-term use by the FDA, a combination of two drugs, phentermine and fenfluramine, or phentermine and dexflenfluramine, popularly known as fen-phen, was used by millions of Americans to promote weight loss. Fenfluramine and dexfenfluramine were eventually associated with valvular heart disease, and the manufacturer withdrew these medications from the marketplace in 1997.

The FDA has approved two medications, sibutramine and orlistat, for long-term use in the treatment of obesity. Sibutramine (sold under the brand name Meridia) increases fullness, making the required dietary changes for weight loss and the maintenance of weight loss easier to accomplish. Unlike dexfenfluramine and fenfluramine, sibutramine does not appear to be associated with valvular heart disease, although a small number of patients may develop significant increases in blood pressure. Orlistat (sold under the brand name Xenical) works by blocking the absorption of fat. Scientists are also investigating the hormone leptin, which plays a role in obesity in mice, as a possible treatment for obesity in humans.

Over a six-month period, weight-loss medications may result in a 10-percent body weight reduction. Weight loss slows or stops after six months, and discontinuing medication usually causes weight regain. The continued use of medications keeps most of the lost weight from returning for two years. Many experts recommend that medications for weight control be used continuously, like medications for diabetes mellitus and hypertension. Unfortunately, few studies have examined the consequences of long-term use of weight-control medications.

Surgery

Surgery may be a weight-loss option for patients who are severely obese (with a BMI of 40 or above) and suffer from serious medical complications due to weight. While the number of people in the United States who qualify for surgery remains small, the percentage of Americans with a BMI of 40 or above increased from less than 1 percent in 1990 to 2.2 percent in 2000.

There are two accepted surgical procedures for reducing body weight: gastroplasty and gastric bypass. Although these two procedures use different surgical methods, they both reduce the stomach to a pouch that is smaller than a chicken’s egg, drastically limiting the amount of food that can be consumed at one time. Surgery produces 25 to 35 percent reductions in weight over the first year and most of this weight loss is maintained five years after surgery. More importantly, the serious medical conditions that accompany extreme obesity improve significantly. Surgery is not without risk and should be performed by skilled surgeons who also provide patients with a comprehensive program for long-term weight control.

The Seven Wonders of the World

The Seven Wonders of the World were works of art and architecture considered by the ancient Greeks and Romans to be the most fabulous creations of antiquity. They were the Pyramids of Egypt, The Hanging Gardens of Babylon, The Temple of Artemis, The Statue of Zeus, The Mausoleum of Halicarnassus, The Colossus of Rhodes, and The Pharos of Alexandria.

1. Temple of Artemis-The Temple of Artemis is depicted in a fanciful reconstruction based on an Italian Renaissance church in this hand-colored engraving by Dutch artist Maarten van Heemskerck. Built in Ephesus in Asia Minor in 356 bc, the Greek temple was considered to be one of the Seven Wonders of the World. It was destroyed by the Goths in ad 262.

2. Colossus of Rhodes-The Colossus of Rhodes, depicted in this hand-colored engraving by Maarten van Heemskerck, was built about 280 bc. Standing 30 m (100 ft) high, it was built to guard the entrance to the harbor at Rhodes. The ancient Greeks and Romans considered it to be one of the Seven Wonders of the World.

3. Pharos of Alexandria-The Pharos of Alexandria, an ancient lighthouse, is depicted in this hand-colored engraving by Maarten van Heemskerck. The lighthouse stood on an island in the harbor of Alexandria and was over 134 m (440 ft) tall. It was considered to be one of the Seven Wonders of the World.

4. Hanging Gardens of Babylon -This hand-colored engraving by 16th century Dutch artist Maarten van Heemskerck depicts the Hanging Gardens of Babylon, one of the Seven Wonders of the World. Technically, the gardens did not hang, but grew on the roofs and terraces of the royal palace in Babylon. Nebuchadnezzar II, the Chaldean king, probably built the gardens in about 600 bc as a consolation to his Median wife who missed the natural surroundings of her homeland.

5. Mausoleum of Halicarnassus-The Mausoleum of Halicarnassus, depicted in this hand-colored engraving by Maarten van Heemskerck, was built about 353 bc. The mausoleum was a huge marble tomb built for King Mausolus of Caria in Asia Minor. It was considered to be one of the Seven Wonders of the World.

6. Statue of Zeus -The Greek sculptor Phidias created the 12-m (40-ft) tall Statue of Zeus in about 435 bc. The statue, depicted in this engraving by 16th-century Dutch artist Maarten van Heemskerck, stood in Olympia and was perhaps the most famous sculpture in ancient Greece. Phidias made the god’s robe and ornaments from gold and carved the body out of ivory.

7.Pyramids of Egypt-Of the Seven Wonders of the World, the famous pyramids located in Giza, near the city of Cairo, Egypt, are the only ones remaining nearly intact. They are depicted here in an engraving by 16th-century Dutch artist Maarten van Heemskerck.

Mona Lisa

Mona Lisa (1503-1506), painted by the Italian artist Leonardo da Vinci, was also known as La Gioconda, possibly referring to the subject’s husband, banker Zanobi del Giocondo. The artist’s use of very deep space in the background with a close-in portrait is typical of Renaissance painting style. The painting hangs in the Louvre, Paris.

Statue of Liberty

The Statue of Liberty, a symbol of freedom for many, was one of the first sights to welcome immigrants arriving in the United States. The statue stands 93 m (305 ft) tall on Liberty Island in New York Harbor. It was designed by French sculptor Frédéric-Auguste Bartholdi and is a gift from France commemmorating the first centennial of U.S. independence from Britain.