Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. For adults, the World Health Organisation (WHO) defines overweight as a BMI greater than or equal to 25 and obesity as a BMI greater than or equal to 30.
It is estimated that approximately 600 million people in the world are obese. This number has more than doubled since 1980. In Australia in 2012, 35.3% of the population were overweight while 27.5% were obese according to the Australian Health Survey.
Causes & Risk Factors
Obesity and overweight are caused by an energy imbalance between the calories consumed and the calories used up by the body. Your body converts these excess calories into fatty substances, triggering obesity.
The most common causes of obesity include:
- Sedentary and physically inactive lifestyle
- Unhealthy diet and eating habits
- Lack of proper sleep
- Diseases such as Hypothyroidism and depression
- Medications such as steroids, anti-depressants, anti-seizure and diabetic medications.
Risk factors for obesity include advancing age, being female and having a family history of obesity.
Signs & Symptoms
Becoming obese is a gradual process.
The usual signs observed in patients with obesity include:
- Feeling tightness or discomfort and needing large-sized clothes
- Inability to use public transportation due to the size of the seats
- Difficulty with day-to-day tasks, especially those that require movement
- Feeling tired and short of breath frequently
- Carrying an increased circumference around the waist
- Having a high body mass index (BMI) equal to or over 30
- Having low self-esteem
Consequences of obesity
Obesity is one of the leading causes of preventable death and impaired quality of life. It is an important underlying cause for a number of serious and chronic disease conditions such as:
- Heart problems
- High blood pressure
- Cancers such as endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon.
You may also have problems related to
- Breathing (e.g. obstructive sleep apnoea)
- Joints (e.g., arthritis)
- Gastrointestinal tract (gallstones)
- Fertility and pregnancy
Your doctor diagnoses obesity based on a complete physical examination including your weight, waist circumference, medical history, and blood tests.
Your doctor will also assess the amount of fat content in your body by calculating your Body Mass Index (BMI). Body mass index (BMI) is a calculation of weight-to-height that is commonly used to classify overweight and obesity in adults.
The goal of treating obesity is to facilitate weight loss and help you achieve a healthy weight. Treatment is centred on balancing the intake of energy (in the form of food) and the expenditure of this energy (in the form of activity). Obesity treatment options include lifestyle modifications, weight loss medications and weight loss surgery.
Lifestyle modifications that help to reduce body weight include dietary changes, physical activity, and behavioural changes.
- Dietary changes include eating healthy food rich in nutrients while avoiding high-calorie, highly processed junk foods.
- Being physically active helps you lose weight and maintain your weight.
- Behavioural changes include adopting healthier habits to reduce your eating triggers (such as watching TV, listening to music or chatting with friends while eating); avoiding stress; and participating in a weight loss program.
- Weight-loss medications or appetite suppressant medications may be prescribed when lifestyle modifications do not help promote weight loss. Medication can also be prescribed to manage underlying conditions causing obesity.
- Weight-loss surgery, also known as bariatric surgery, is considered only in patients with extreme obesity. Weight loss surgery treats obesity either by limiting the amount of food stored in the stomach, limiting absorption of food, or both. The available surgical options for weight-loss include:
- Laparoscopic adjustable gastric banding (LAGB) or lap band surgery involves separating your stomach into a small upper pouch and a larger lower pouch using an adjustable band. The food intake is restricted or limited by adjusting the band. This procedure is minimally invasive, and offers slow and steady weight-loss.
- Sleeve gastrectomy involves reducing the size of the stomach by stapling and removing a large part of the stomach to reduce the absorption of food.
- Gastric bypass surgery, also called Roux-en-Y gastric bypass, involves creating a small pouch on top your stomach and bypassing the flow of food directly to the small intestine, thereby avoiding absorption from the remaining part of the stomach.
- Biliopancreatic diversion (BPD) with duodenal switch is a complex surgical procedure which involves removing a large portion of the stomach and bypassing the food flow away from the upper portion of the small intestine. This procedure offers significant weight loss, but can be associated with several complications.