I am going to share enough here so that you can do your own research, and if necessary, especially if you are taking blood pressure medications or have health issues, can discuss this with your doctor.
If I mention a site, please note that I have no affiliation with the site, I am not benefiting in any way by sharing the site with you, in fact, it is probably a US Government health site. I am not sure if it is accessible around the world.
First I purchased a book called "The DASH Diet for Hypertension" by Thomas Moore, MD. On the cover it says "Lower Your Blood Pressure in 14 Days Without Drugs". I purchased the Kindle eBook. You can probably find it by clicking on one of the books below, then searching at the Amazon site.
Next I did a search online, and found more concise information about amounts to eat, etc., that I could print. I found this at the U.S. Department of Health and Human Services National Inst. of Health (NIH) site, in National Heart, Lung, and Blood Inst. section. You can click the hyperlinked text, or copy and paste the following into your browser - www.nhlbi.nih.gov/health/health-topics/topics/dash/ It gives you the basics, and then along the left you will find links with further information about the diet including "Benefits", "Following Dash", "Healthy Lifestyle", and "Getting Started". They give you a general amount of food to eat within food categories within certain calorie ranges. I chose 1400 Calories to start.
Some things that you have to remember if you are doing this for weight loss is that the examples of foods in the "Vegetables" list, for example, include everything from potatoes to much less carbohydrate-rich foods...so you have to realize that for many people, if you chose to eat only a potato for every vegetable you can eat on a particular day, you're not eating balanced and aren't likely to lose as much weight as if you had chosen to include green beans, salad greens, and other veggies low in or free of carbohydrates.
I also made myself a simple chart to keep a tally of the foods I eat in a day in the calorie range I chose. I have made free printable charts for you to use with various calorie ranges, you will find links to them below.
When doing the diet, my blood pressure levels were normal in the morning, and lower than they were in the afternoon, but not quite down to normal in the afternoon. If I don't stick with the diet, levels are a bit more elevated.
With this diet, you are learning to eat sodium in moderation...I am reading labels more and they suggest that you look for sodium levels of around 5% on whatever foods you eat...you need sodium, just not nearly as much as most eat. Processed and canned foods are notorious for containing too much sodium, so become a label reader. DASH suggests about 2300 mg. of sodium each day.
ALSO, and this is what makes the diet more than just eating lower sodium, if you eat the foods as suggested, you are getting proper amounts of potassium, calcium, and magnesium and other nutrients important for normalizing blood pressure. It is up to you whether you want to supplement as well...but consider the following first.
If you are on blood pressure medications, or being watched by your doctor because blood pressure levels are starting to climb, it's important to let your doctor know you want to start this diet. (I will admit my doctor doesn't feel that the diet works, but she feels that way about many of the alternative approaches I take to health, so unless dangerous for my health, we have to agree to disagree.)
As for the medications, they very likely have you on medications that affect sodium and potassium levels (with unpleasant side affects for some, like me). Doing something like this diet that has further affect on these levels may be harmful, so talk to your doctor.
The diet isn't harmful if you aren't taking medications in my opinion, but that is my opinion, and if you aren't using certain herbs and supplements to regulate you blood pressure...you have to know how to balance it all.
I hope this has helped you understand more about how the DASH Diet works, or has worked for me, and given you a few resources should you like to give it a try, with your Doctor's okay if needed.
NOTE: A serving size is the amount indicated on the packaging, which is often a lot less than we are inclined to eat.
1200 Calorie DASH Diet Chart
1400 Calorie DASH Diet Chart
1600 Calorie DASH Diet Chart
1800 Calorie DASH Diet Chart
2000 Calorie DASH Diet Chart
2600 Calorie DASH Diet Chart
You may also be interested in another article I have written, "How to Replace NutriSystem with your Own Foods".
I hope this page and the printable DASH Diet Charts will be helpful to you.