I'd love to have your barley, sausage, and tomatoes recipe! That sounds good, but also well-outside my culinary experience Is that a regional dish?
I think this is the part that is the key to answering the question! For some diabetics (even LADA), diet and exercise alone can control diabetes for a while. For most of us, if we live long enough, that routine we've gotten into ceases working effectively after a period of time elapses, and adjustments are needed. Sometimes that adjustment is more exercise or different food, and sometimes it's using medications.
Often, when I hear this question, I tend to clarify and ask if it needs another clause on the end. Are we really being asked:
"can diet and exercise alone control diabetes, for the rest of my life?
And the sensible answer to that question is: "Maybe, but probably not." Another way it is phrased online is "can diabetes be reversed or cured with diet and exercise?" Lot's of scammers would have us believe so, but most of us at this point have figured it out.