Diabetes: one size doesn’t fit all

Just when we think we have a handle on a disease, that’s precisely a good time to sit back and reflect on how complex it really is.

And the Garvan Insitute’s Head of the Diabetes and Obesity Program, Professor David James, has done just that in a new essay published in the latest issue of Diabetes Management Journal.

In the essay James challenges our assumptions about diabetes, such as about its causes and main treatment targets, and even whether obesity is always a bad thing.

The standard picture is that people living in industrialised countries live sedentary lives, while at the same time eating too much high-fat, high-sugar food. As a result, they become obese and develop ‘insulin resistance’, a reduced ability to use insulin for carbohydrate metabolism. The pancreas compensates by producing ever-increasing amounts of insulin, until it becomes exhausted and diabetes develops.

“When we look at the worldwide obesity epidemic, and the number of people developing diabetes, we tend to make sweeping generalisations, try to make one size fit all,” said James.

“Not only does one size not fit all, but our approach might end up compromising, or even endangering, people’s health.

“One obvious example is the notion that all obesity is bad. While in most cases it’s true that obesity is very bad for health, there is a considerable sub-group of obese people – around 20 per cent – who are metabolically healthy.

“A recent study showed that when you force these ‘healthy obese’ people to lose weight by putting them on calorie restricted diets, their metabolism gets worse. So arguably those people are living in an equilibrium that for them is perfectly fine.

“Then we have the French – they eat lots of fat in their diets, and their daily calorie intake is as high as any of us, and yet they remain thinner and succumb less to diabetes. Why is that? No-one knows.

“I’m not saying that too much nutrition is not a factor, when it’s clearly central. I am saying that it’s impossible to stop people from eating food.

“If you can’t stop people eating food, you have to find a solution elsewhere. That’s when the open road turns into a myriad of back alleys and dead ends – or unanticipated traffic jams.

“To give an example, one arm of diabetes research focuses on allowing the pancreas to keep producing ever-increasing amounts of insulin to compensate for ‘insulin resistance,’ the diabetic’s reduced ability to use insulin effectively for glucose uptake.

“The problem is that insulin has many functions in the body. Flooding the system may solve the problem of insulin resistance, but it exacerbates fat synthesis, so people would end up with hypertriglyceridemia, which causes severe cardiovascular problems.

“We must remember that the body is a finely tuned mechanism, so tampering with parts of it before you can see the big picture could have many unpleasant and unforeseen effects.”

The essay was published today in the Diabetes Management Journal, which is produced by Diabetes Australia.