Dr Jeremy Krebs
At the same time, obesity in the general population has increased by 50 per cent in the last two decades. Obesity and diabetes are two sides of the same coin, and Dr Jeremy Krebs and colleagues at the University of Otago, Wellington, are determined to find the right kind of diet to reduce these negative statistics.
"To reduce type 2 diabetes we must get people to lose weight and, more importantly, keep it off. Most people can do this if they stick to a diet; the trick is to find a regimen where you're going to lose weight and keep it off, long term. That's the big public health challenge and we haven't solved it yet," he says.
Obesity is the most important modifiable risk factor for type 2 diabetes and also makes established diabetes more difficult to control. This is because an increase in fat storage causes the body to become resistant to the effects of the insulin from the pancreas.
Weight loss can reverse this and, in some people with early type 2 diabetes, weight loss returns blood sugar levels to normal.
Krebs explains that, over the past two decades, obese people with diabetes have been put on a low-fat/high-carbohydrate diet, but this hasn't worked well. The diet is difficult to stick to, and it is often sabotaged by increases in refined carbohydrate rather than a focus on reducing fat and increasing fibre.
He has now received Health Research Council funding to find a better way.
"We want to compare this low-fat/high-carb diet with a diet which we think will be easier to follow in the long term; beyond two years. This is a diet higher in protein and lower in carbohydrate, but not as low as the Atkins diet.
"Short-term studies in people without diabetes have indicated that diets higher in protein with lower levels of carbohydrate may be easier to follow and give the same, or greater, health benefits. Now we want to see if this is true for people with diabetes over a longer term."
The study will involve 450 obese people with type 2 diabetes in Auckland, Wellington and Christchurch, who will be randomised to the two different diets and closely monitored over two years.
Weight loss, along with diabetes control, cardiovascular disease, adverse effects and cost-effectiveness are also being assessed.
It will also involve assistance through a group-based diet programme, as well as individual support from a dietitian to ascertain which regimen works best.
Krebs says if this alternative high-protein/low-carb diet keeps weight off in the long term, without significant adverse effects, it will have wide-ranging public health implications for both obesity and type 2 diabetes in New Zealand and overseas.
FUNDING
Health Research Council