What Is Obesity?

Majority of internationally recognised scientific and medical organisations, including the World Health Organisation, view obesity as a chronic progressive disease that requires life long treatment and control. While lifestyle factors contribute significantly to the development of obesity, it is increasingly acknowledged that genetic and other environmental factors contribute to one’s chances of becoming obese.

Obesity has many serious economic, social and psychological costs on individuals who suffer from the disease.

How Is Obesity Measured?

The most commonly used of these is the Body Mass Index (BMI) measurement. BMI is calculated by measuring an individuals’ weight in kilograms before dividing it by their height in metres squared. Once calculated, a person can figure out how they rank by assessing which category their score fits into.

Category BMI Score
Normal Weight 18.9 – 24.9
Overweight 25 – 29.9
Class I, Obesity 30 – 34.9
Class II, Serious Obesity 35 – 39.9
Class III, Severe Obesity 40 and over

Obesity in Australia

Australia has one of the highest rates of obesity in the world, with more than 5 million Australian adults and children possessing a BMI of over 30. According to studies by Monash University, obesity has overtaken cigarette smoking as the number one cause of premature death in Australia. The rate of obesity is increasing so rapidly that at current rates, over 80% of all Australian adults and a third of all children will be obese by 2025.

Causes of Obesity

Genetics are considered a strong factor, however there are also many psychological, cultural, behavioural, hormonal and metabolic factors that contribute to each individual’s likelihood of becoming obese. Some of these include:

1. Positive Energy Balance

A positive energy balance occurs when a person consumes more calories than they expend on a daily basis. It occurs as a result of either over eating, eating foods high in fat, sugar or high fructose corn syrup or a lack of exercise in most cases, and is a major cause of obesity. Other causes of a positive energy balance include stress, lack of sleep and various medications.

2. Weight Gain

Weight gain, particularly rapid weight gain, causes a number of hormonal and metabolic changes to the body. Among other effects, these changes reduce the body’s ability to burn fat for energy, increase the conversion of carbohydrates such as glucose to fat and increase the body’s capacity to store fat in adipose tissue. Rapid weight gain also affects many of the brain’s receptors that regulate energy consumption and hunger, which leads to sufferers requiring larger meals more frequently to satisfy their needs. Weight gain also contributes to the development of other diseases such as hypertension, diabetes, heart disease and osteoarthritis.

This is part of the reason why obesity is considered a progressive disease, specifically the idea that “obesity begets obesity” and once obese it is particularly difficult to return to a healthy weight.

3. Psychological Causes

Psychological and emotional distress are common side effects from obesity. This in turn leads to hormonal changes that increase appetite and limit the ability to burn fat.

4.Lifestyle Causes

In many cases, obesity is triggered by an unhealthy lifestyle. This can include a lack of exercise, overconsumption of unhealthy foods or a combination of the two.

Diet and Obesity?

In terms of treating obesity, a low calorie, low sugar diet is the most effective and recommended diet for sufferers of the disease. However, dieting itself can have a negative impact. When a person loses weight, the body ‘thinks’ it is starving and energy expenditure is reduced in order to conserve calories. The reduction in energy expenditure with dietary weight loss requires that, in order to maintain weight loss, the dieter eat even fewer calories than someone of equal body size who has never been on a diet. However, eating less is difficult following a diet because there are long-term changes in regulators of appetite that increase the desire to eat and the amount of food that can be consumed. Such diet-induced changes lead to a positive energy balance and weight regain and, because the conditions responsible for the reduction in energy expenditure and increased drive to eat persist long-term, an individual will often not only regain all of their lost weight, but even more.

In addition, diets can also have a negative impact on a subject’s metabolism. With dietary weight-loss, the amount of dietary fat the body burns is reduced by approximately 50 percent. In addition, dieting reduces the amount of fat the body burns for fuel during low-grade activity such as walking, cleaning the house, fixing dinner, or working on a computer. The reduction in the amount of fat that is burned for fuel following a dietary weight-loss makes more fat available to be stored, and dieting increases the capacity for fat depots to store even more fat than before a diet.

Therefore, while dietary changes are necessary when seeking to lose weight, it is very easy for them to fail and prove not only ineffective but cause a subject to gain even more weight than previously. It is necessary to consult with a dietician before creating a meal plan to ensure you have a diet that suits your personal needs, wants and lifestyle.

Health concerns and morbid obesity?

The most significant would be type 2 diabetes. This condition reduces longevity by as much as 35 percent and is a major cause for amputations, cardiovascular disease, stroke, blindness and numerous other complications including kidney disease, hypertension, lipid abnormalities, circulatory and nerve defects, hard-to-heal infections, impotence, and more.

Other potential complications from morbid obesity include heart disease, hypertension, sleep apnea, liver disease and a higher risk of developing Alzehimer’s disease. If you suffer from any of these in addition to obesity, please discuss them with your doctor before deciding on a plan of action to combat your obesity.


There are a number of environmental, psychological, hormonal, metabolic and social factors (among others) that contribute to the development of obesity. The progressive nature of the disease means that an imbalance in one of these factors that leads to obesity eventually imbalances all the factors in question, leading to a vicious cycle where weight loss options becomes significantly limited. If you are obese and concerned about your weight, it is necessary to speak with your doctor to discuss your options and which is the best fit.