A year ago I walked into a Walmart store to decided to check my blood pressure at the blood pressure monitoring machine they place next to the pharmacy. I was surprised to note that my numbers were high (160/100).
My daily diet was not all that healthy. This is when I read online that weight loss could help. I was heavier too(BMI > 25). I followed a strict diet for about 3 months. It turned out that it did indeed help. Over the 3 month time frame I kept constant track of my blood pressure every day along with my body weight. I charted them over this time frame, and the results speak for itself.

On the left Y-axis is the weight, and on the right is my systolic blood pressure. The chart shows that when I lost 20lbs I was able to bring down my BP. But as I continued to lose weight, the marginal returns were diminishing, almost absent. Some added changes to my lifestyle, like taking a 15 minute walk in the afternoon, has bought down my blood pressure to more reasonable levels. I'll blog about the diet I followed to get this weight loss later.
Summary: Eat right, eat healthy and lose weight :)