Obesity Education

Obesity and Type II Diabetes

Obesity Australia Ltd, ABN 75 150 799 929 (Obesity Australia) 13 March 2014, By Professor Joseph Proietto, University of Melbourne

The current obesity epidemic is causing an increase in the prevalence of Type 2 diabetes. How does obesity cause diabetes?

Type 1 (Juvenile) diabetes is caused by the destruction of the cells that make insulin by the immune system. The high glucose is caused by lack of insulin and the treatment is insulin replacement by daily insulin injections.

In contrast, Type 2 diabetes is associated with insulin resistance, a condition where the action of insulin to lower blood glucose is not normal. This means that the cells that make insulin (β cells) have to produce more insulin to maintain normal glucose levels. Most people with insulin resistance live their lives with high circulating insulin but never develop diabetes because the β cells can cope with the increased demand. Diabetes comes when the β cells start to fail. For the β cells to fail two factors are required 1) a genetic predisposition 2) a metabolic toxin. So far only a few genes have been identified that give diabetes susceptibility. What are the metabolic toxins?

Fat is the most important metabolic toxin. There are some individuals who make new fat cells easily. These subjects store excess fat in fat cells and remain metabolically normal. They do not develop insulin resistance. However these people are rare, most people cannot increase their fat cell number enough and the extra fat is stored in muscles, in the liver and also in β cells, causing insulin resistance in muscle and liver and a defect in insulin secretion in the β cells. This is how obesity precipitates type 2 diabetes.

It follows then that the best treatment for Type 2 diabetes is weight loss.

Obesity and Cardiac Disease

Obesity Australia Ltd, ABN 75 150 799 929 (Obesity Australia) 4 August 2013, By Professor Gary Wittert, Discipline of Medicine, University of Adelaide

Obesity Australia Ltd, ABN 75 150 799 929 (Obesity Australia.

Obesity increases the work of the heart. A larger blood volume needs to be ejected with each beat. This results in an enlargement/thickening of the muscle that forms the chambers of the heart. This will be made worse if there is also high blood pressure (hypertension) present. Also the left atrium enlarges, predisposing to an abnormal rhythm known as atrial fibrillation.

Furthermore when fat is concentrated in the abdomen and around the heart there is more likely to be inflammation and metabolic abnormalities (abnormal sugar and fat metabolism and insulin resistance) which promote blockage of blood vessels, abnormal function of the electrical system of the heart, and weakening and ultimately failure of the heart muscle.

It is possible for obesity to occur without a concomitant increased risk of cardiovascular disease. Such individuals typically have the fat situated mainly under the skin and not in the abdomen, they have a relatively large amount of muscle mass, a healthy eating pattern, and are physically active (1).

Although obesity in and of itself is a risk factor for cardiac disease there are a number of other mechanisms by which the effect of obesity might be mediated for example:

  • Hypertension (high blood pressure). Obese individuals are six times more likely to have high blood pressure than those who are lean. In young people an abnormal increase in weight is associated with a marked increase in the risk of subsequently developing high blood pressure. A high blood pressure increases the risk for stroke and heart attacks (2).
  • Obstructive Sleep Apnoea (OSA; see section on sleep) further aggravates the situation by increasing blood pressure. It also produces stress and strain on the wall of the heart leading to further muscle thickening and weakening, and further enlargement of the left atrium. OSA also makes obesity worse, causes abnormal blood sugar metabolism and ultimately contributes to type II diabetes and it also increases inflammation (3).

Weight loss can reverse, particularly early on, or at least substantially improve, the cardiac abnormalities that occur with obesity (4).

Heart failure

Severe obesity is a cause of heart failure independent of other cardiovascular risk factors (5). The problem begins with a failure of the muscle to relax so that the chambers cannot fill with blood. Therefore a reduced amount is ejected with each beat. Subsequently the muscle becomes weak so that it is unable to completely empty the chamber with each beat.

Initially the affected person may experience mild shortness of breath on activity. As the problem progresses lower leg swelling, and increasing shortness of breath occurs, even at rest. Paradoxically in the elderly with heart failure those with obesity do better and survive longer than those with a lower body mass index.

Atrial fibrillation

Obesity is a cause of atrial fibrillation. As a result insufficient blood is pumped out of the heart which leads to fatigue and shortness of breath and also dizziness. Because of the abnormal rhythm clots can form and travel to the brain causing a stroke.

Compared to a normal weight individual, one with obesity has twice the risk of atrial fibrillation. Although many obesity related conditions such as hypertension, ischaemic heart disease, and obstructive sleep apnoea may mediate the effect of obesity to induce atrial fibrillation, obesity remains a risk factor even after accounting for these other factors (6).

Ischaemic heart disease

When fatty deposits partially block the blood vessels that supply the heart muscle with oxygen affected individuals may experience chest pain on exertion, while eating, or in response to emotion. This is called angina. When the narrowing becomes almost complete chest pain may occur at rest (called unstable angina) and if the blockage is complete and not cleared rapidly then a portion of the heart muscle may die and this is called a myocardial infarction or heart attack. Ischaemic heart disease (IHD) or coronary artery disease is the name given to the group of these conditions.

Smoking, excessive blood cholesterol, high alcohol intake and genetic factors may all increase the risk of IHD. Obesity, particularly when the fat is in the abdomen, is associated with increased blood levels of cholesterol and other blood fats, sugar, and inflammatory molecules. These all increase the risk of IHD. Even independent of these, obesity increases the risk of IHD. The more factors, the higher the risk (7), but even after accounting for all these factors obesity increases the risk.


  1. Hamer M, Stamatakis E. Metabolically healthy obesity and risk of all-cause and cardiovascular disease mortality. The Journal of clinical endocrinology and metabolism. 2012;97(7):2482-8.
  2. Landsberg L, Aronne LJ, Beilin LJ, Burke V, Igel LI, Lloyd-Jones D, et al. Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment: a position paper of The Obesity Society and the American Society of Hypertension. Journal of clinical hypertension. 2013;15(1):14-33.
  3. Garvey JF, Taylor CT, McNicholas WT. Cardiovascular disease in obstructive sleep apnoea syndrome: the role of intermittent hypoxia and inflammation. The European respiratory journal. 2009;33(5):1195-205.
  4. Vest AR, Heneghan HM, Agarwal S, Schauer PR, Young JB. Bariatric surgery and cardiovascular outcomes: a systematic review. Heart. 2012;98(24):1763-77.
  5. Djousse L, Bartz TM, Ix JH, Zieman SJ, Delaney JA, Mukamal KJ, et al. Adiposity and incident heart failure in older adults: the cardiovascular health study. Obesity. 2012;20(9):1936-41..
  6. Abed HS, Wittert GA. Obesity and atrial fibrillation. Obesity reviews : an official journal of the International Association for the Study of Obesity. 2013. Epub 2013/07/25.
  7. Merry AH, Erkens PM, Boer JM, Schouten LJ, Feskens EJ, Verschuren WM, et al. Co-occurrence of metabolic factors and the risk of coronary heart disease: a prospective cohort study in the Netherlands. International journal of cardiology. 2012;155(2):223-9.

Obesity and Mental Health

Obesity Australia Ltd, ABN 75 150 799 929 (Obesity Australia)

1 April 2014, By Professor John Dixon, Baker IDI

Contrary to the saying “fat and happy,” obesity is generally not a state of happiness at all, and is very often associated with major psychological burden and depression. Depression is an important condition that is far more commonly found in obese Australians, especially those with severe obesity and complications such as diabetes and sleep disturbance. The problem is often compounded by low income, poor employment opportunity, and very low self-esteem associated with guilt and a perceived lack of willpower.

Depression, psychological disturbance, poor self esteem and eating disorders, such as binge eating disorder, often cluster together in young and middle aged women, making treatment very difficult. Imagine trying to lose weight with an appropriate healthy diet and suddenly losing control, eating excessively in a binge, feeling terribly ashamed - guilty - and “undoing all the good work”. This is a devastating blow to self worth and can also perpetuate the weight problem, which is actually a chronic disease that was set in motion before birth or during early childhood – far from a mere failure of willpower.

Of course we cannot separate the psychological, physical, chemical and hormonal aspects of obesity out in a simplistic way, and the more we look the more inter-connected they are. Psychological stress leads to hormone and chemical patterns that generate a higher risk of diabetes, heart disease, sleep disturbance and cancer; conditions which in turn aggravate tiredness, lethargy and depression. Add to this joint pain and barriers to physical activity and we have a picture of frustration and despair – “and it’s entirely my fault.

Approaching the relationship between obesity and mental health from the other end, modern medicine has developed effective therapies for many debilitating mental health problems including schizophrenia and severe depression. However, some of our most effective medications for these conditions cause hunger, weight gain and increased risk of type 2 diabetes and heart disease. It is important that we find ways to prevent these unwanted side-effects while enabling successful control of serious mental illness.

The depression, stress and psychological disturbance experienced by many obese Australians are very real, being generated by the disease itself and by society’s broad pejorative perceptions about this disease. These perceptions must change if health care services are to engage those suffering obesity in a constructive way to manage their chronic disease and its associated major psychological burden. It is not all about weight loss; improved quality of life, psychological wellbeing, physical function, and adequately treating complications of obesity including depression are keys to improving health outcomes and the lives of those suffering from the complex disease “obesity.”


Presently, there are no scheduled obesity educational seminars being facilitated by North Queensland Obesity Surgery Centre. We encourage you to contact us directly or speak with your General Practicioner.

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