To a great degree, we can delay the onset of type 2 diabetes. Changing your diet and losing weight have proven highly effective in people at risk, including those with a family history of diabetes, mothers with gestational diabetes, obese people, those in certain high-risk ethnic groups, and people with high blood pressure and high cholesterol. Several nutritional strategies and diabetes-treating medications have also proven effective. However, there are adverse side effects from medications that can outweigh benefits. We now have a better understanding of the evolution of diabetes and it is hoped that we will have safer and durable alternatives soon.
We do know that lifestyle changes (weight loss/diet and exercise) are very effective and carry no practical adverse metabolic or cardiovascular risk. Anyone can be a candidate. A good starting point is to speak with your health care provider.