One out of every 2 adults in Hawaii is either prediabetic or diabetic, but many don’t know it.

Take actor Peter Togawa, who is fit and trim and a regular on “Hawaii Five-0.” He never looked the part of a prediabetic and was surprised when a doctor told him his blood sugar was elevated.

Comedian Frank De Lima was more typecast for the role when he tipped the scale at 320 pounds. He went on to develop type 2 diabetes, a chronic condition that can be devastating when uncontrolled.

Both entertainers have managed to reverse course with diet and lifestyle changes, and they want others to do the same. They are teaming up with the state Health Department on “Prevent Diabetes Hawaii,” a public campaign starting Monday to alert people of the increasing risk of developing diabetes.

The goal is to get local residents to take a 30-second quiz online at PreventDiabetesHawaii.com to assess their risk — and then take action. The website offers tips and resources for individual lifestyle changes as well as nationally recognized Diabetes Prevention Programs, offered at local health centers and YMCAs. Health care providers can download materials for waiting rooms and for use with patients.

If not controlled, diabetes can lead to blindness, kidney failure, stroke and heart disease. It is the seventh leading cause of death in Hawaii. But structured behavior interventions such as the Diabetes Prevention Programs can cut the risk in half.

“The good news is that you can reverse prediabetes with basic lifestyle changes,” Dr. Virginia Pressler, state health director, said Friday. “It’s very important for people to get screened early and take action.”

The publicity effort will run through June on television, in malls and at community health centers. The effort, including developing and running the website, print and television ads, cost $350,000 and was funded by the state with support from the U.S. Centers for Disease Control.

Altogether, 442,000 adults in Hawaii have prediabetes and 154,000 have diabetes, and those numbers have been rising, according to the Health Department. Native Hawaiians, Pacific Islanders and Filipinos have the highest rates of diabetes in the islands, followed by people of Japanese ancestry. Nearly two-thirds of adults who have prediabetes don’t realize it.

“Our population is disproportionately affected by this disease,” said Lola Irvin, administrator of the Chronic Disease Prevention and Health Promotion Division. “You don’t have to be obese to be at risk. For the Asian population, weight gain is not as much of a driver for prediabetes.”

Because Togawa found out early that he was prediabetic, he could ward off the problem with relatively minor changes in diet and exercise.

“I was never overweight, I was always active,” he said at a news conference announcing the campaign. “My wife, she was the one that told me — excuse me, she was the one that strongly encouraged me — to go see a doctor when I hit the right age. And I was surprised to discover that I had prediabetes.”

“I was happy that I did get it checked and I have it in control. It’s been a lifestyle change and a lifelong change,” he said. “Diabetes is serious, but with education and support it doesn’t have to be scary. Anybody can take control of their life.”

Togawa was frustrated at first when reducing portions and eating healthier options didn’t do the trick. What worked for him was picking up the pace with cardiovascular exercise.

“What I discovered that did work for me was not lifting weights; it was the cardio,” he said. “I love golf, but instead of riding, I walk. And when I walk, I walk at a brisk pace.”

The Health Department encourages people to “rethink their drink” and shift to water, and to eat whole grains, brown rice, vegetables and fruit rather than refined products. But Pressler said people don’t need to give up everything they love to eat.

“To deprive someone of the things they enjoy the most is not effective,” she said. “It’s a matter of serving size and recognizing it’s a treat, rather than a daily staple.”

De Lima grew up with fresh treats his mother baked every day for the family. As an adult he would eat “whatever,” chowing down with his friends after his evening comedy shows. He was shocked when his doctor told him to lose 100 pounds. But he worked with friends to make it happen, shifting his diet to things like fish, brown rice and veggies.

“I lost the weight, and I controlled my type 2 diabetes,” said De Lima, now 210 pounds. “I am off the medication. The doctor is happy. … I am very, very happy that I am a part of this (campaign). I hope everyone takes an interest in it. Spread the word to those that haven’t heard. Go take the test.”