Andy Holmes Investigates Influence of Microbes on Obesity

Associate Professor Andy Holmes is currently investigating the interplay between the human body's microbiota and the nutrients in various foods consumed, and the significance that this has to weight gain and obesity.

Following a study conducted by researchers from the US and Britain, results emerged demonstrating that energy expenditure among 'hunter-gatherer' adults in northern Tanzania was similar to those living more Westernized, convenient lifestyles across Europe and the US, writes Melissa Davey in the Sydney Morning Herald. The study concluded that the rise in 'modern' diseases such as obesity, cardiovascular disease and diabetes in the Western world is a result of increased food consumption.

However, Andy has contested that the difference between calories expended and calories consumed, does not always result in the storage of fat. In his study of individual human microbiota - the system of microbes in the body which includes bacteria, Andy has recognised that the human gut responds differently to various nutrients in food, which has an enormous impact on metabolism and health. As a result, it has become apparent that the gut reaction to food is more relevant than the amount of calories in the food itself, when it comes to weight gain. The results of studies in the area show that obese people have microbes that cause them to 'readily store fat after absorbing kilojoules much more efficiently than a slim, healthy person'.

Andy is also looking at the influence of environment and diet on an individual's microbiota, in order to understand the variation in how consumed calories are used in different people. He has concluded that it is a combination of what microbes people are exposed to through their environment, diet and time span. Andy is currently collaborating with Professor of Biological Sciences, Stephen Simpson, and looking into how micobiota can be changed and how all the different components of one's diet can impact on gut microbiota.

Andy's advanced research in this area is largely contributing to our understanding of the obesity epidemic, and accentuates the fact that health is so much more complicated than simply diet and exercise. Read more about Andy's research in this area here.