As people around the globe continue to get fatter, diabetes rates will continue to rise and insulin supplies will be in short supply, a new study warns.

By 2030, an estimated 79 million adults with Type 2 diabetes are expected to need insulin. But if current quantities of the medicine remain level, as many as 40 million sufferers could be left without it, according to a report in the journal The Lancet Diabetes and Endocrinology.

“These estimates suggest that current levels of insulin access are highly inadequate compared to projected need, especially in Africa and Asia,” explained Dr. Sanjay Basu, an assistant professor of medicine at Stanford University. “And more efforts should be devoted to overcoming this looming health challenge.”

Insulin is used to treat those with Type 1 diabetes and some people with Type 2 diabetes, which is linked to obesity and little physical activity.

Researchers predict that the number of adults with Type 2 diabetes will rocket 25 percent from 406 million in 2018 to 511 million in 2030. The U.S. is expected to be the third-largest population with diabetes sufferers at 32 million in a little more than a decade.

“The number of adults with Type 2 diabetes is expected to rise over the next 12 years due to aging, urbanization and associated changes in diet and physical activity,” said Basu.

While nearly 80 million people could be in need of insulin, only 38 million are likely to have access to it, based on current numbers. Also, the expensive treatment is dominated by three manufacturers.