Lee Chung Horn
                                                                          NO LIMITS TO CARING
    Diabetes & Endocrinology  






Obesity is a chronic, metabolic disease caused by multiple and complex inherited and acquired factors, including excessive calorie and food intake, decreased physical activity, and genetic influences. The defining characteristic is excess body fat.

Long-term treatment and management are required to achieve and sustain weight loss. Obesity, particularly when associated with unhealthy patterns of body fat distribution, results in 300,000 preventable deaths each year in the U.S. and $100 billion in health care costs.

Causes of Obesity

An excess of body fat results from an imbalance between energy intake and energy output (i.e., consuming more calories than are needed to support your body's energy needs). Factors that promote obesity include genes, family history of obesity, behavioral factors (such as a high fat diet and sedentary lifestyle), and biochemical differences (lower metabolic rate or decreased ability to oxidize fat).

Measurement of Obesity

It can be difficult to measure accurately the proportion of a person's body that is composed of fat. However, an accepted indicator of obesity and its risks is the Body Mass Index (BMI), which takes into account body weight and height. To calculate your BMI number, divide your weight in kilograms by your height in meters squared.

A BMI of 30 suggests “obesity”. A BMI of 25 means that you are "overweight." In Asians, a lower BMI of 22 indicates “overweight”, and BMI of 25 indicates obesity.

Checking skinfold thickness and bioelectrical impedance are two other methods of measuring fatness. These tests help to differentiate between weight that is attributable to fat accumulation and weight that represents muscle development.

Health Implications

A number of conditions worsen as obesity increases and often improve as obesity is successfully treated. Some of these conditions are:

• Cardiovascular (heart) disease
• High blood pressure
• Gallstones
• Type 2 diabetes
• Elevated blood cholesterol and triglyceride levels
• Gout
• Sleep apnea/obesity hypoventilation syndrome
• Osteoarthritis of the weight bearing joints
• Infertility

Obesity also increases the risk for developing some forms of cancer (i.e., breast, colorectal).

Scientific studies show that upper body obesity, particularly excess fat within the abdominal cavity (visceral fat), increases health risks more than fat accumulation in the lower body (hips and thighs). Higher proportions of visceral fat are associated with higher risks of insulin resistance, diabetes, high blood pressure and atherosclerosis , leading to cardiovascular disease (heart disease and strokes).

How can you estimate your body fat distribution?

Look at yourself in the mirror. If you are more apple-shaped than pear-shaped, you probably have visceral fat accumulation. A more precise approach is to use the Waist/Hip (WHR) ratio. For women, visceral fat accumulation is indicated by a WHR greater than 0.8. For a man, visceral fat accumulation is indicated by a WHR greater than 1.0. A newer measurement uses only the waist circumference.

Treatment Options

There is an abundance of clinical data showing that losing as little as five to ten percent of body weight and maintaining that loss can significantly improve the health of obese patients. For that reason, persons who are diagnosed as being clinically obese should seek treatment. The principal phases of treatment are:

1) stopping weight gain
2) reducing weight to a level that diminishes the health risk to the individual
3) maintaining weight at the lower level
4) improving your diet
5) being physically more active
6) improving health care practices

What can I do?

The following would help:

• lower calorie diets
• increased physical activity
• lifestyle change
• drug therapies to enhance the weight loss process
• surgery (for every obese individuals)

Current Drug Therapies

Sibutramine (Reductil or Meridia) increases the levels of both serotonin and noradrenaline in areas of the brain that regulate food intake and body weight. It reduces some complications of obesity, such as those involving blood glucose and lipids. The side-effects may include dry mouth, lethargy, drowsiness, and insomnia.

Orlistat (Xenical) is unique among current obesity drugs in that it does not act directly on the central nervous system. It inhibits and enzyme (pancreatic lipase) essential to fat digestion. The most common side effects were intestinal symptoms, including cramping, gas and diarrhea - particularly in patients who ate high-fat foods against their doctors' advice.

Duromine acts on the brain to produce a sensation of fullness (satiety). Common side effects are dry mouth, insomnia and constipation.

All these medications are approved by the FDA and Singapore's Health Sciences Authority.

Types of Obesity Surgery

Several procedures have been proven to help promote significant weight loss. These include stapling the stomach or banding the stomach to make it smaller, gastric bypass operations, jaw wiring. Contrary to popular belief, liposuction, the most frequent cosmetic operation in the United States in which fat tissue is removed, seldom succeeds in leading to significant weight loss. Successful obesity surgery may lead to a loss of up to 60% of excess weight mostly in the first year and often continuing up to 5 years.

What about slimming centers, lifestyle centers and herbal supplements?

Beware of seductive advertising in the media. None of these approaches have been shown scientifically to be effective or safe. Women patients are often the target of unscrupulous advertisers.


Copyright of Lee Chung Horn Diabetes & Endocrinology 2009