Could you control diabetes with proper dieting?

Sometimes. The answer to this depends on a few factors: what type of diabetes you have (1 or 2), how many years you have had it for, your starting weight and whether you are overweight to begin with, genetic factors, etc. If you have newly diagnosed type 2 diabetes, are overweight, and lead an unhealthy lifestyle, you can control your diabetes by losing a significant amt of weight w/ healthy diet+exercise.
Can help. Diet, exercise and weight loss will definitely help with type 2 (or even type 1) diabetes -- it's the cornerstone of therapy. However, most people will need medication to help control their blood sugar. Talk w/your doctor.