Can i prevent high blood pressure by adopting a healthy diet?

Sometimes.: Some high blood pressure is inevitable; as we get older, arteries naturally stiffen some and this can increase BP and even a good diet can't always help. But a healthy diet can certainly delay high blood pressure in those who are suceptible and outright prevent it in many more. Those who are "salt sensitive" will especially benefit from a healthy diet, and weight loss make huge difference.

Yes: Diet and exercise can help you. If overweight, try to attain a normal weight. Some foods like bananas which are high in potassium, can help lower BP in people with high blood pressure.