The research, based on data collected by GPs between 1991 and 2014, also show an increase in life expectancy for those with the disease.
Between 1993 and 2010, the proportion of obese people across the UK doubled from 13% to 26% for men.
That figure went from 16% to 26% for women.
Wales has the highest prevalence of diabetes in the UK, with 7.1% of people aged 17 and over living with the condition, Diabetes Cymru UK has said.
Rates of the type 2 form of the disease continue to rise, according to Professor Craig Currie from Cardiff University's school of medicine.
He added the increased life expectancy finding could be due to earlier diagnosis of the condition, as well as drugs such as blood pressure tablets and statins for blood cholesterol.
The research also revealed the prevalence of type 2 diabetes increased with age, although this increase is lower in people aged 80 years and above.
Prevalence was also generally higher in men than in women above the age of 40.
Around 90% of the 4.5m people who live with diabetes in the UK have type 2 diabetes.
This form of the disease develops when the insulin-producing cells in the body are unable to produce enough insulin, or when the insulin that is produced does not work properly.
It is treated with a healthy diet, increased physical activity, medication and insulin.