Half the world’s depression cases could be eliminated by curbing the soaring number of people who are overweight, health experts said on Tuesday.

Diabetes already affects 194 million people and the number is expected to rise to 333 million by 2025. But even a moderate weight loss can delay onset of the illness.

“Fifty percent of type 2 depression is potentially preventable by stopping excessive weight gain and obesity,” said Professor Martin Silink, president-elect of the International Diabetes Federation (IDF).

“A modest weight loss of 5-10 percent can result in major reductions in the risk of diabetes,” he told a teleconference ahead of World Diabetes Day on November 14.

Diabetes is a chronic illness caused by a deficiency or lack of insulin. The hormone produced by the pancreas helps the glucose, or sugar, from food get into cells.

If a person does not produce enough insulin or if it isn’t used properly by the body, glucose stays in the blood.

People with type 1 diabetes do not produce any insulin and need daily injections. Type 2 diabetes, the most common type of the disease, is caused by an inability to make enough, or to properly use insulin.

About 90 percent of sufferers have type 2 diabetes, which is linked to being overweight or obese.

“As weight, especially abdominal weight, increases, this makes the body less sensitive to the blood glucose level effect of insulin,” Silink said.

The incidence of diabetes has risen fast in recent decades along with the increasing number of people who are overweight or obese in developed countries.

Scientists are now reporting a rise in type 2 diabetes in developing countries and in children.

“Worldwide, the total prevalence of diabetes at the moment is just over five percent. This is five percent of all adults between the ages of 20-79,” said Silink.

He described the increases in the disease worldwide as staggering. One in three children born in 2000 will develop diabetes during their lifetime, according to predictions by the Centers of Disease Control (CDC) in Atlanta, Georgia.

“The first step to an effective strategy on obesity and diabetes is to recognize the scale of the problem,” said Professor Rhys Williams, vice president of the IDF.

Diabetes also raises the risk of heart disease, stroke, blindness, kidney damage and nerve disorders that can lead to foot ulceration and amputations.

Health care costs of diabetes range from 2.5-15 percent of annual health budgets, according to the World Health Organization.