Our obesity research

Garvan's obesity research is diverse and far-reaching. We're using the latest technology to translate scientific discoveries direct to the clinic. Some of our obesity focus areas include:

prediabetes and how the microbiome affects blood sugar
the impact of bariatric surgery on health
the link between inflammation and obesity
and the role of brown fat and blood sugar levels.

If you want to help make a difference, please support our research.

Key areas of investigation

Dr Dorit Samocha-Bonet

Your microbiome and prediabetes

One of the major conditions travelling hand-in-hand with obesity is prediabetes – the precursor to type 2 diabetes. Prediabetes affects around 25% of Australian adults.

Prediabetes can fly under the radar for years – until the symptoms crash down like Jenga blocks. Prediabetes on its own is a risk factor for everything that diabetes can herald – cardiovascular disease, certain types of cancer, fatty liver.

But if we’re aware of prediabetes (and being overweight is one of the warning signs) there’s a lot we can do.

This is the focus of Garvan’s new clinical trial PREDICT.

“When you are already diagnosed with diabetes, it can be too late for your pancreas, because your body has been dealing with insulin resistance for many years. But during prediabetes it’s possible to prevent the development of type 2 diabetes,” says Garvan’s Dr Dorit Samocha-Bonet.

It seems like the solution is straightforward – lose weight and prevent diabetes. But many people struggle to lose weight and keep it off.

Also, weight loss does not reverse prediabetes in everybody. “On average, weight loss of about 5% of body weight, if maintained, is very beneficial for health. But we see in the clinic, and it has been documented in medical literature, that many individuals who lose a large amount of body weight and fat, do not reverse prediabetes.

“Glucose regulation remains impaired in these individuals. It’s clear that weight loss as a blanket treatment for everybody isn’t the whole story in battling the prediabetes epidemic.”

Scientists are investigating the role of the microorganisms living in our gut (our microbiome) in the current diabetes epidemic. “Our collaborators at the Weizmann Institute in Israel have shown that the sugar response to food can be predicted by the composition of the gut microorganisms and other clinical and blood parameters.”

“We also know that the drug metformin makes people more sensitive to insulin – it fights insulin resistance – but we’re still figuring out the exact mechanism. It’s emerging that metformin affects the gut microorganisms in a positive way,” says Dorit.

The genetic makeup of the billions of microorganisms in your gut could be the differentiator in how well your body processes sugar after meals and how you respond to common treatments.

“At the moment, our standard of care for a person with prediabetes is to advise a low fat, low sugar diet and try to be more active, to lose weight. But we’re looking for more precise ways to treat people.”

We hope the PREDICT study findings will lead to better tools for clinicians to guide patients on medication, diet and lifestyle choices. This will hopefully stop prediabetes from progressing to full-blown type 2 diabetes and assist those living with diabetes manage their health and improve quality of life.

Read more about the Clinical Insulin Resistance group

Prof Katherine Samaras

Weight loss and the impact of bariatric surgery

One area of research undertaken by obesity and diabetes researchers at Garvan is understanding how weight loss improves human health and improves diabetes and related diseases. Professor Katherine Samaras, working with a team that includes scientists, cardiologists and surgeons, has been examining the impact of bariatric surgery on health.

Modest weight loss, even five kilograms, improves many health problems. It improves diabetes control, blood pressure, cholesterol and systemic inflammation. It prevents the development of diabetes in those with a high risk.

Bariatric procedures, such as gastric banding, sleeve gastrectomy and gastric bypass are proven, effective treatments for obesity, particularly where diabetes co-exists.

Prof Mark Febbraio

Fat sends inflammation messages to the immune system

Did you know that fat sends messages to the immune system that can affect your risk of diabetes and other diseases? Researchers from Garvan and the Baker Institute are making sense of how these messages are sent, and how they might be intercepted to halt the development of disease.

Researchers believe that inflammation could be the missing link between obesity and its associated diseases. Although inflammation plays an important role in defending the body during infection, prolonged inflammation (such as in obesity) can help other diseases thrive in the body.

Prof Jerry Greenfield

Brown fat and blood sugar levels

Garvan scientists have shown that brown fat – a type of fat that burns energy to keep us warm – can also help keep blood sugar steady in adults.

We measured brown fat activity and blood glucose continuously in real time in study participants, and found that individuals with more brown fat had smaller fluctuations in blood sugar.

The incidence of type 2 diabetes, which is characterised by high blood sugar, is reaching epidemic proportions worldwide. There is a need for new insights into how blood sugar levels can be controlled, beyond mechanisms actioned by currently available therapies.

Unlike white fat, which primarily stores energy, brown fat burns energy – often in remarkably large amounts. Sitting just above the collarbone and in the neck, brown fat acts like a heat generator, helping to keep us warm by burning sugar and fat.

Associate Professor Jerry Greenfield, of Garvan’s Diabetes and Metabolism Division, has long been interested in whether brown fat might have a role beyond keeping us cosy.

“Previously, we showed that individuals with large brown fat stores tend to be lean and have lower blood glucose – and now, we’ve uncovered a potential link between brown fat activity and blood glucose variations”.

The research team studied a group of 15 healthy adults over 12 hours. They found that blood glucose levels and heat production by brown fat were closely related, tracking together over time.

Importantly, participants who had larger deposits of brown fat had less fluctuation in blood glucose – and blood glucose fell after each peak of brown fat activity surge.

In contrast, brown fat activity rose only in response to an increase in blood glucose among those with less brown fat, and interestingly, their glucose fluctuations were greater. Notably, individuals with no detectable brown fat had the widest fluctuations in blood glucose.

It looks like the more brown fat one has, the more influence it has on blood glucose.

Our findings indicate that brown fat might act as a ‘glucose buffer’, lessening the variation in blood glucose and potentially diminishing metabolic stresses that could increase the risk of diabetes.

The researchers also observed that brown fat activity rose at dawn, around the time volunteers were waking from sleep. We speculate that this early morning temperature boost may have an evolutionary origin, generating heat and preparing our ancestors for hunting and gathering in the cold as the day begins.

Brown fat-based therapies are potentially promising in the fight against diabetes in the future, but also urges caution.

“The study brings brown fat into the frame for developing diabetes therapies. If we can pinpoint what switches brown fat’s activity on and off during the day, we may identify new targets in drug design.

“Brown fat is interesting and promising – but it is not the solution to finding a cure for diabetes, at least not now. A balanced diet and regular exercise are the cornerstones of healthy metabolism and should not be forgotten.”

Read more about Clinical Diabetes, Appetite and Metabolism

Our obesity research

Key areas of investigation

Your microbiome and prediabetes

Weight loss and the impact of bariatric surgery

Fat sends inflammation messages to the immune system

Brown fat and blood sugar levels

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Our obesity research

Key areas of investigation

Your microbiome and prediabetes

Weight loss and the impact of bariatric surgery

Fat sends inflammation messages to the immune system

Brown fat and blood sugar levels

Contact us