The research, conducted by Australian diabetes researchers Dr Arthur Jenkins and Dr Marijka Batterham from the University of Wollongong in conjunction with Professor Lesley Campbell, Director of Diabetes Services at St Vincent’s Hospital (Sydney) and researcher at the Garvan Institute of Medical Research, is published in PLOS ONE (online from 1700 ET on 7 August 2013).
Over the last 25 years, Professor Campbell has gathered detailed information of more than 300 healthy people with a family history of type 2 diabetes, including their body shape, size and composition (using Dual-energy X-ray absorptiometry to obtain accurate measurements). Specifically, her research looks at people who are genetically at risk of developing Type 2 diabetes and are overweight or obese before they get the disease.
The information gathered by Professor Campbell was analysed by Dr Jenkins using a specially constructed mathematical model. He concluded that many genes are responsible for obesity, with each affected family likely to tell a slightly different genetic story.
“We can see that there are many, many different ways in which the system can go wrong, with more variety than commonality,” Dr Jenkins said.
“In my opinion, the current quest to develop a single anti-obesity drug is misguided – because there are too many potential problems to be targeted by a single drug, or indeed any small number of drugs.”
“It’s likely that the same is true of type 2 diabetes. The underlying cause is genetic and the genetic causes are very rare, but there are many differences between people.”
“Rare genetic defects account for something like 95 per cent of the total problem. That is a very unwelcome fact for most people, who would like to think an easy solution is close at hand.”
Professor Campbell stresses that genes bring out underlying predispositions, and there are fairly predictable interactions between genes and environment. So if people are predisposed to a strong appetite, large amounts of easily available, highly palatable, food are likely to make them fat.
“The reason we see so many people getting fat is that they carry strong hunger genes…it’s an obesogenic environment that rewards eating,” Professor Campbell said.
“People no longer have to go fishing, or hunting and gathering in order to eat. They just go to McDonald’s, or KFC, or the freezer. The point is that people don’t have to expend any energy to get an abundance of food, often high in fat or sugar.”
“We have shown in previous studies that people with diabetes in the family tend to be hungry more often, are able to eat more at a sitting, and will generally opt to eat high calorie foods. This does not mean they are ‘greedy’, it just means that their bodies are genetically driven to eat more.”
“The same genes would serve these people well in times of food scarcity or famine. They would survive, while their leaner neighbours would perish.”
MEDIA CONTACTS: For interviews with Professor Lesley Campbell regarding the public health implications of this study, please contact Alison Heather, Science Communications Manager, Garvan Institute of Medical Research on +61 2 9295 8128, +61 434 071 326 or A.firstname.lastname@example.org. For interviews regarding the scientific or technical aspects of the research, please contact Dr Arthur Jenkins via email at email@example.com.