The Global Patient Portal Glossary provides accurate and highly consumable definitions of key terms used on the website, in relation to overweight and obesity.




Bariatric Surgery  - A weight-loss procedure performed by health professionals to assist those seeking to lose weight. Bariatric surgery is often performed on individuals with a BMI exceeding 40. The procedure on the stomach and/or intestines is recommended to patients affected by conditions attributable to increased weight, including diabetes or heart disease. The term is used interchangeably with ‘gastrointestinal surgery’.

Gastrointestinal surgery is subdivided into three main types; Gastric band surgery, Gastric sleeve surgery and Gastric bypass surgery. There are advantages and disadvantages to each, and the surgeon will use different techniques to create a ‘pouch’.

[See definitions: Gastric Band Surgery, Gastric Bypass Surgery and Gastric Sleeve Surgery]

For more information, click here.

Body Mass Index - Body Mass Index (BMI) is a measure often used in conjunction with waist circumference to quantify whether individuals are ‘healthy’ or ‘ideal’ weight. This measure classifies individuals as underweight, healthy weight, overweight, or obese based on two numerical values; weight and height.

To calculate BMI, you divide weight (KG) by height (M2). When investigating BMI amongst children, clinicians often prefer to compare the calculated value to those attained from other individuals of the same sex and age.

More information on Body Mass Index can be found on the World Health Organisation BMI Database



Calorie - A calorie is equal to one unit of energy. The term is a measure of both energy expenditure and energy stored in the body. When considering diet i.e. the calories we eat and burn, we refer to kilocalories (kcal). Calories in your diet come from carbohydrates, fats protein and alcohol.

Communicable Disease - Communicable diseases (CDs), also defined ‘infectious diseases’ are those that spread both directly and indirectly from person to person or from animal to person. They are caused by bacteria, viruses, parasites or fungi.



Diabetes - A lifelong condition characterised by elevated blood sugar, or glucose levels. Individuals with diabetes are unable to acquire the energy that comes from glucose in their diet due to a lack of/ inability to use the hormone insulin. This can cause complications including damage to the eyes, kidney and nerves. 

[see definitions: Gestational Diabetes, Type 1 Diabetes, Type 2 Diabetes]

Double Burden of Disease - The ‘Double Burden of Disease’ is used to highlight the existence of multiple non-communicable and/or communicable diseases at a given time. When considering obesity, the ‘Double Burden of Nutrition’ is highly applicable and is recognised by researchers. i.e. over nutrition and undernutrition co-existing amongst the same population, household or across the life course.



Energy Expenditure - Energy Expenditure (measured in calories) is the term used to quantify how much energy an individual expends in a day. Calories are consumed to fuel basic procedures performed by our body including breathing, digesting food and transporting blood through the body’s vessels. It is also increased substantially during physical activity.

Exercise - A physically demanding activity that is performed to support and enhance overall health and wellbeing.





Gastric Band Surgery - Gastric band surgery constitutes insertion of an inflatable band with an adjustable opening at the top of the stomach.

Gastric Bypass Surgery - Gastric bypass surgery attaches the top of the stomach to the small intestine.

Gastric Sleeve Surgery - Gastric sleeve surgery removes approximately 80% of the stomach.

Gestational Diabetes - A subtype of diabetes that can occur during any stage of a pregnancy, although most common in the second half/trimester. Having a BMI above healthy weight contributes to the risk of developing the condition.



Healthy Weight - Individuals are most often classified as ‘healthy weight’ if they fall within the according category of the Body Mass Index (BMI) measure [see definition]. Having a healthy weight helps to reduce the chance of developing obesity related conditions including diabetes and heart disease.

Heart Disease - A medical condition resulting from issues and deformities in the heart organ of the body. The term is often used broadly to describe any disorder of the heart, such as congenital and coronary heart disease (CHD).

High Blood Pressure - High blood pressure, also known as ‘hypertension’ occurs when your blood pressure is equal to or exceeds 140/90mmHg. According to clinical guidelines a reading between 90/60mmHg and 120/80mmHg is optimal. Complications associated with elevated blood pressure include an exacerbated risk of heart attacks, heart disease or strokes. 



Insulin - A hormone that functions as a regulator of blood sugar/glucose levels. It is made by the Pancreas and fulfils its role by moving glucose from the blood stream into muscles and tissues in the body.









Malnutrition - Known as ‘poor nutrition’, the life-threatening condition arises when your diet contains an inadequate composition of nutrients. It encompasses both undernutrition (lack of nutrients) and over nutrition (overdose of nutrients).

Metabolic Syndrome - A patient diagnosed with ‘metabolic syndrome’ has a multitude of medical conditions that together increase the risk of them developing heart disease and diabetes. Contributing factors include high blood pressure and sugar levels, in addition to a large waist circumference.



Non Communicable Disease - Non-communicable diseases (NCDs), also defined ‘chronic diseases’, are non-infectious diseases that arise due to genetic, physiological, environmental and behavioural factors. They tend to occur later in life yet last longer than communicable diseases [see definition]. Obesity is considered as a NCD.

To access the WHO fact sheet on NCDs click here.

Nutrition - According to the World Health Organisation, Nutrition is the ‘intake of food, considered in relation to the body’s dietary needs’. Incorporating a well-balanced diet into daily life combined with regular periods of physical activity contributes to ‘good nutrition’.

Nutrition is vital for health and well-being and increases immunity, decreases susceptibility to disease, as well as strengthening physical/mental development and productivity.



Obesity - Obesity is a medical condition described as excess body weight in the form of fat. When accumulated, this fat can lead to severe health impairments. The prevalence of obesity across the world continues to rise, and this is now recognised as one of the most important public health problems facing the world today.

Click here to read our ‘obesity is a disease’ statement.

Overweight - Having excessive amounts of body weight (muscle, bone, fat, and water) broadly defines the term. Individuals are classified as ‘overweight’ if they fall within the according category of the Body Mass Index (BMI) measure [see definition]. It is important to take into consideration that the measure does not measure body fat directly. 











Type 1 Diabetes - This sub-type of diabetes occurs when your body does not produce any insulin. It is less common than Type 2 Diabetes [see definition] and usually prevails in children and young adults.

Type 2 Diabetes - This sub-type of diabetes occurs when your body does not produce enough insulin, or is unable to utilise the insulin that is produced. Type 2 Diabetes is more common amongst the population and often develops over a period of time.







Waist Circumference - Waist Circumference (WC) assesses the size of an individual's waistline to estimate the likelihood of developing obesity related health conditions including high blood pressure, high blood cholesterol, heart disease and type-2 diabetes.

World Health Organisation - Founded in 1948, the World Health Organisation (WHO) is the specialised agency of the United Nations. They are concerned with building a better, healthier future for people all over the world.