The BBC has reported that the diabetes drugs bill was £75.7m in 2013-14, £73.2m last year and £74.2m in 2011-12. Another £6.1m went on obesity prescriptions over the same three-year period.
Conservative health spokesman, Jackson Carlaw, who obtained the figures, said: "Not every case of diabetes is related to weight, there are a range of reasons.
"But the fact prescriptions for both diabetes and obesity are rising at an alarming rate year-on-year cannot be ignored.
"While we need the NHS and Scottish government to do all they can to force through messages on healthy living, it isn't just down to them. There has to be a level of personal responsibility.
The Scottish government has responded by pointing out that obesity and diabetes are increasing Europe-wide.
Latest statistics suggest nearly a quarter of a million people in Scotland now have diabetes, almost 5% of the population. The majority of sufferers, about 220,000, have type 2 diabetes.
A total of 3.34 million items were dispensed to treat diabetes in Scotland in 2013-14.