The Ultimate Guide to Fasting and Blood Pressure

October 9, 2020

We recommend fasting a lot on this blog, mostly because caloric restriction is one of the few defined modifiers of autophagy, the chemical process of longevity. But, there are some reasons to beware of fasting. In this guide, we’ll go over the relationship between fasting and blood sugar to help you find out if you’re at risk. 


But first, why does blood sugar? Well, high blood sugar levels are a key indicator of diabetes, a serious diet-related ailment. While looking around, you might have seen articles that fasting is actually good for people with diabetes. While the research around this is solid, the link between fasting and improvement of the diabetes condition is still in its infancy, and people with prediabetes and diabetes should consult a physician before going on a fasting regimen.


So, how do you use blood sugar to determine whether it’s safe for you to fast? First, get a blood sugar measurement device like a test meter. Second, go on a short fast, such as a single week of a 5/2 diet. Fasting for such a short time shouldn’t hurt you in any way, though of course if something does appear to be wrong you should stop the fast immediately. Once you finish a week of fasting, your blood sugar levels should be normalized to how they would be if you were doing it long term. Here’s how to read the results:


  • <100 mg/dl - Nondiabetic. You’ll be fine to fast in the long-term.
  • 100 - 125 mg/dl - Prediabetic. In this case you’re in the group that early research suggests this might be good for, so ask your doctor about it before continuing any further.
  • >126 mg/dl - Diabetic. In this case fasting can hurt you, and you should not continue. 


If you find out you can’t fast, don’t be too bummed out. There’s a lot more proven strategies to improve your healthspan out there, such as having a plant-rich diet or even building social relationships. You can read up on our site for all the habits you can do to help boost your longevity!


Old and healthy isn't a myth.
There's so much more to aging than what meets the eye. We're out to make a healthier, happier world.
start your journey