Poor levels of fitness and nutrition are impacting on the nation's health in a number of ways, one of which is reflected in high levels of diabetes.
Natasha Marsland, diabetes care advisor at the charity, said that while type-1 diabetes is associated with genetics, obesity is "directly linked" to type-2 diabetes, the most common form of the condition.
She explained: "The extra fat that you are carrying prevents the action of the insulin and it is the insulin which allows the body to regulate its own blood glucose levels.
"So if you are carrying extra weight it makes the insulin that your body is producing not as effective."
The expert claimed that by losing weight, a person can reduce their risk of type-2 diabetes by as much as 58 per cent.