High Blood Pressure and the Low Carbohydrate Diet

Ketogenic Diets Effectively Lower Blood Pressure by Dana Carpender
Photo by Marcelo Leal on Unsplash

Originally published 10/4/2000, Updated 09/19/2019.

  What You Need to Know

  • A low carbohydrate diet not only does not increase blood pressure, but it actually lowers it for many people.
  • A low carbohydrate diet is naturally diuretic, so be careful with water pills, and make sure you drink an adequate amount of water.
  • Potassium and magnesium are the two main minerals that are affected by the water loss inherent in low carbohydrate dieting.

Christy DeBoerHello, fellow low carbers. It’s nice to be back. 

I decided to pick out a question on high blood pressure and the low carbohydrate diet for this article. The question has been asked several times by different people, and I think that it’s an important one.



Can A Low Carbohydrate Diet Cause High Blood Pressure?

There are many things that happen to your body to cause your blood pressure to increase. I have been asking this question of physicians that I know, and the consensus is that they feel that obesity is a much greater risk factor than any diet. They would prefer that their patients lost the weight on a low carbohydrate diet and just monitored their blood pressure to make sure that it did not get dangerously high. There was also a general consensus that they actually saw their patients’ blood pressures decrease when they followed a low carbohydrate regime.

What About Salt?

What About Salt?
Standard medical advice has always been for people with high blood pressure to reduce their sodium intake. Why would blood pressure decrease when so many low carbers crave salty foods and increase their sodium intake? There is a fairly simple answer to this question. Excess salt consumption can cause excess fluid retention, which can lead to an increase in blood pressure. However, a low carbohydrate diet puts one into ketosis and is naturally diuretic. This helps to reduce the excess fluids in the body, thereby reducing the blood pressure. When your body does not have to pump the extra fluid around it is much happier. Many people on a low carbohydrate diet will notice a significant decrease in their blood pressure as a result of this.

What About High Blood Pressure Medication?

I strongly encourage people who take blood pressure medication to monitor their blood pressure frequently. With the combination of the low carbohydrate regime and the subsequent weight loss lowering the blood pressure, and the blood pressure medication lowering the blood pressure, problems could arise where the blood pressure could actually dip too low. I find that a lot of people who lose weight on a low carbohydrate diet have been able to discontinue their blood pressure medication completely. I do not recommend people stop taking those medications just because they are on this diet, though. (You should never discontinue taking medication prescribed by your doctor without consulting with him/her!) Merely monitor your blood pressure and, if it gets too low, discuss with your physician the possibility of either lowering the dosage of your medication or getting off of it entirely.

What Are The Symptoms Of Low Blood Pressure?

The main symptom of low blood pressure is dizziness upon standing. It is a feeling of lightheadedness when you get up quickly. It usually happens when you first get out of bed in the morning. You jump up and all of a sudden have to sit back down because your blood pressure is too low. This is one of the first indicators. If you notice that you are having dizziness, are lightheaded, blacking out, passing out, falling down, unsteady on your feet, or confused, you need to make sure your blood pressure is not too low.

How Do You Know If Your Blood Pressure Is Too Low?

When you are monitoring your blood pressure it should not drop more than 20 points below it’s normal. For example, if you normally run a blood pressure of 120/80, a drop to 100/60 would be too low of a drop for you. This could indicate that your blood pressure is dropping too quickly. Any blood pressure below 100/60 is troublesome.

There is always the exception to the rule, however. There are a few people who always have a blood pressure of less than 100/60. So for them, I would watch and see if it drops 20 points and call that too low.

Why You Still Need To Drink Plenty Of Water

Why You Still Need To Drink Plenty Of Water
Photo by Kate Joie on Unsplash

While it is not good for your heart to have to pump excess fluid throughout your body, it is also not good for you to be dehydrated and not have enough fluid in your system. Low carbers in particular need to consume plenty of fluids, preferably water, to keep themselves adequately hydrated. We not only need the fluids to maintain an optimal balance in our bodies, but we need them to flush the toxins released from our fat out of our systems. Be sure to drink a minimum of 64 ounces of water with an additional 8 ounces for every 25 pounds you want to lose every day!

The Importance Of Vitamins

The Importance Of Vitamins
Photo by pina messina on Unsplash

Along with the loss of water on a low carbohydrate diet is a loss of important vitamins and minerals. Many are flushed from our systems right along with the toxins produced by our weight loss. It is important to take a good multivitamin. Be sure to take one that has both potassium and magnesium in it. Potassium and magnesium are the two main minerals that are affected by the water loss inherent in low carbohydrate dieting.

Have you been experiencing leg cramps since beginning a low carbohydrate diet? If your answer is yes, then you most probably have a deficiency of potassium and magnesium. The leg cramps are a sign that your body is out of balance and needs these minerals.

In Conclusion

  • A low carbohydrate diet not only does not increase blood pressure, but it actually lowers it for many people. If you are taking blood pressure medications, you should monitor your blood pressure more frequently than you may have been doing, and discuss any changes in your medications or dosages with your doctor before you make them.
  • A low carbohydrate diet is naturally diuretic, so be careful with water pills, and make sure you drink an adequate amount of water and take, at the minimum, a good multivitamin containing both potassium and magnesium, since these are the minerals most easily lost.

The best of luck and health to you all.

Until next time,

Christy DeBoer R.N.

DISCLAIMER: The information contained on this website has not been evaluated by The Food and Drug Administration. It is not meant to diagnose, treat, cure, or prevent any disease. Individuals starting any diet plan or who are suffering from any disease or illness should consult with a physician or health care professional.

More articles by Christy DeBoer R.N.

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  1. Melanie Petchak APRN, FNP-BC

    After research I’ve learned that being in ketosis can cause the release of catecholamines ( vasoconstrictors) which can result in elevated blood pressure. This has happened to me and even after losing 40 plus pounds my BP continued to rise despite taking Bystolic ( a beta blocking agent). My physician added Norvasc ( a vasodilator) and it’s now normotensive. As I come off of the keto genic diet I will have to monitor my BP very closely to make sure it doesn’t go too low.

    • I have been low carbing for 17 days and have lost 11 pounds. I take atenolol once a day for htn and have for a long time . My blood pressure was fine before I started this diet and now it’s going up. I do feel dehydrated even though I am drinking over 100 ounces of water per day. I’m kind of worried and thinking of doing another diet. I love this diet though because Im not hungry and it’s easy to stick to.

  2. Darn. I tried and feel tons worse low carb. It is clearly not for everyone.

    • Sorry you do not think it worked for you.

      Tell us more about your experience – how long did you try it, what did you eat, how often, etc.?

      A lot of people who try Low-Carb don’t actually do it correctly.


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