Understanding obesity and overweight

What are obesity and overweight?

Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2).

The recommended classifications for BMI adopted by the National Institutes of Health (NIH) and World Health Organization (WHO) are:

  • Underweight – <18.5 kg/m2
  • Normal weight – ≥18.5 to 24.9 kg/m2
  • Overweight – ≥25.0 to 29.9 kg/m2
  • Obesity – ≥30 kg/m2
  • Class I – 30.0 to 34.9 kg/m2
  • Class II – 35.0 to 39.9 kg/m2
  • Class III – ≥40 kg/m2 (also referred to as severe, extreme, or massive obesity)

BMI provides the most useful measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals.


One of the best things you could do to protect and improve your health is to stay informed. Marina Medical provides regular e-newsletter on health information, healthy living tip etc. Click the below button to subscribe to our newsletter.



What causes obesity and overweight?
What causes obesity and overweight?

Reasons that cause obesity and overweight

The fundamental cause of obesity and overweight is an energy imbalance between calories consumed and calories expended. There has been:

  • an increased intake of foods that are high in fat and sugars; and
  • an increase in physical inactivity due to the sedentary nature of work, changing modes of transportation, and increasing urbanization.
What are the common health consequences of overweight and obesity?
What are the common health consequences of overweight and obesity?

Common health consequences of overweight and obesity

Raised BMI is a major risk factor for non-communicable diseases such as:

  • cardiovascular diseases (mainly heart disease and stroke);
  • diabetes;
  • musculoskeletal disorders (especially osteoarthritis – a highly disabling degenerative disease of the joints);
  • some cancers (including endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon).

Childhood obesity is associated with a higher chance of obesity, premature death and disability in adulthood. But in addition to increased future risks, obese children experience breathing difficulties, increased risk of fractures, hypertension, early markers of cardiovascular disease, insulin resistance and psychological effects.

How can overweight and obesity be reduced?
How can overweight and obesity be reduced?

Options to reduce overweight and obesity

Overweight and obesity are largely preventable by choosing healthier foods and regular physical activity. People can limit energy intake from total fats and sugars; increase consumption of fruit and vegetables; engage in regular physical activity (60 minutes a day for children and 150 minutes spread through the week for adults).

How to diagnose overweight and obesity?
How to diagnose overweight and obesity?

Diagnosis of overweight and obesity

To diagnose overweight and obesity, your doctor will perform a physical exam and recommend some tests.

Your doctor may review your weight history, weight-loss efforts, physical activity and exercise habits, eating patterns and appetite control, what other conditions you've had, medications, stress levels, and other issues about your health. Your doctor may also review your family's health history to see if you may be predisposed to certain conditions.

A general physical exam includes measuring your height; checking vital signs, such as heart rate, blood pressure and temperature; listening to your heart and lungs; examining your abdomen. Your doctor will check your body mass index (BMI). Fat stored around the waist, sometimes called visceral fat or abdominal fat, may further increase the risk of heart disease and diabetes. Women with a waist more than 35 inches and men with a waist more than 40 inches may have more health risks

Your doctor will also check for other possible health problems, such as high blood pressure, high cholesterol, underactive thyroid, liver problems and diabetes.

How to deal with obesity?
How to deal with obesity?

Dealing with obesity

The key to successful weight loss is developing healthy diet and exercise habits. You may need to work with a team of health professionals — including a dietitian, behavioural counsellor or physiotherapist— to help you understand and make changes in your eating and activity habits.

Weight-loss medication is often a helpful component in the treatment regimen for people with obesity. The decision to initiate drug therapy should be individualised and made after a careful evaluation of the risks and benefits of all treatment options. Before selecting a medication for you, your doctor will consider your health history, as well as possible side effects.

2023-2024 Influenza Vaccination FAQs (in...

Get In Touch

For any enquiry, please call +852 3420 6622, Whatsapp +852 5228 0810, or info@marinamedical.hk

Preferred language (for consultation only)*:
Preferred Time:
*required fields