An Australian study has found that exercise alone does not protect people from type 2 diabetes if you're overweight.
Health organisation Sax Institute's 45 and Up study of more than 30,000 people reveals maintaining a healthy weight is more effective in preventing type 2 diabetes than being more active.
Thanh-Binh Nguyen from the University of Sydney, lead researcher of the study which was presented in Sydney, said there was a simple way to ensure you avoid the condition.
“If you want to avoid type 2 diabetes, maintaining a healthy weight is really the key.
"Once you are overweight being physically active doesn't help you that much in terms of preventing type 2 diabetes.
"It helps you if you can manage to reduce your weight, so it's important to continue to be physically active and to adopt a healthy diet," Mr Nguyen said.
The research shows that people who are overweight and physically active have twice the risk of developing type 2 diabetes, compared to less active people of normal weight.
For those who are obese, the risk was five times greater, even if they were still physically active.
Jenna Price and Leonie Oakes, who both have a family history of diabetes and showed pre-diabetic symptoms, said they were able to reverse their risk of developing the disease by losing weight.
“I don't have pre-diabetes anymore, and for me, that's a major success, and here I am, much older than my sister when she died, much older than my father when he died," Ms Price said.
Losing just 10 per cent of her body weight, and keeping it off, was enough to make a difference for Ms Oakes.
“My sisters have diabetes, and when I told them I'd reversed [my pre-diabetic symptoms], they were shocked, they had no idea you could reverse it," she said.
Diabetes Australia says small changes in diet, such as reducing portion sizes and swapping to low-fat dairy products, can help people to achieve a healthy body weight and manage diabetes.