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Obesity - What it is

Obesity refers to having excessive body fat. 

Obesity is defined by body mass index (BMI), which is calculated from your height and weight. A person who weighs too much for their height is obese. 

Current international guidelines define being overweight as having a BMI of 25 kg/m2 and above, and being obese as having a BMI of 30 kg/m2 and above. Because Asians have a higher risk of health problems at a lower BMI, we should aim for a BMI of below 23 kg/m2.

Obesity is a major risk factor for many serious health problems such as heart disease, diabetes, high cholesterol, sleep apnoea and some cancers.

Obesity - Symptoms

Obesity - How to prevent?

Obesity - Causes and Risk Factors

The most common thing that increases a person’s risk of being obese is having an unhealthy lifestyle. Often, this is a combination of eating too much, choosing unhealthy foods, and moving too little. 

There are also other factors that contribute to obesity, including taking certain medicines which cause weight gain, or having certain hormonal conditions.

Obesity - Diagnosis

​The body mass index (BMI) is used to diagnose obesity. The World Health Organization classifies BMI ranges as follows:

ClassificationBMI (kg/m2)
Underweight< 18.5
Normal range18.5 – 24.9
Overweight25.0 – 29.9
Obese≥ 30.0

In some instances, additional tests may be required to look for a hormonal problem that may contribute to obesity.

Obesity - Treatments

The goal of obesity treatment is to achieve and maintain a healthy weight. 

For a start, a good weight-loss goal would be to lose 5 – 10% of your initial body weight over 6 months. Weight loss should be done in a gradual and safe way, and should not exceed 0.5 – 1kg per week.

Lifestyle change

Having a healthy lifestyle is by far the most important factor in achieving weight loss. This includes:
  • Reducing the number of calories in your diet
  • Making healthy food choices
  • Getting enough exercise (at least 30 minutes a day of moderate-intensity exercise on most days of the week)
In some cases, advice from a dietician, physiotherapist or obesity specialist may be needed. This may help you to make practical and effective changes to your eating and exercise habits.

Weight-loss medications

A healthy diet and regular exercise are crucial to losing weight. However, in certain situations, additional weight-loss medication may help. It is important to remember that weight-loss medication will only work if a healthy lifestyle is maintained. Your doctor will consider your medical history and possible side effects of each medication before selecting one that is right for you. Medications approved for weight management in Singapore include orlistat and phentermine.

Weight-loss surgery

In some situations, weight-loss surgery (bariatric surgery) is an option. Weight-loss surgery works by limiting the amount of food you can eat, or decreases the absorption of food, or both. It is a very effective way to lose weight and improve obesity-related health problems. However, it requires motivation, commitment and a long-term lifestyle change. People who have a BMI above 40 kg/m2, or a BMI above 35 kg/m2 with one or more obesity-related health problems may consider weight-loss surgery after discussion with an obesity specialist.

Obesity - Preparing for surgery

Obesity - Post-surgery care

Obesity - Other Information

​SGH Obesity Centre

Specialist Outpatient Clinic, Level 3
10 Hospital Boulevard, SingHealth Tower / Outram Community Hospital
Singapore 168582

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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