Can I control diabetes without medication?

Depends . On how severe your diabetes is- speak with your pcp or endo. But there are many well tolerated diabetes meds that might help you keep it mild longer.
Some can but tricky. Some people have very mild diabetes that can be controlled with diet only, but this is rare. Most individuals have had the disease for some time before they are diagnosed and by that point require oral medications or insulin.
Type 1 no. 2 maybe. Type 1 diabetes must be treated with Insulin (plus sometimes other meds). Type 2 can be treated with lifestyle modification early in the disease process, but often the body needs some help from meds.