Friday, October 28, 2016

I Just Did a 5-Day Water Fast was more like 4 1/2 days. But they say that at 3 days is when you've burned through your ready reserves of glucose and that's when the fast really begins.

I'd done a few 24-hour fasts in the past 6 months after hearing a lot about the health benefits, but it was just a couple weeks ago when I was informed of this study that it can yield a dramatic improvement for high blood pressure, my Achilles heel. My bold in the abstract.


One hundred seventy-four consecutive hypertensive patients with blood pressure in excess of 140 mm Hg systolic, 90 mm Hg diastolic (140/90 mm Hg), or both were treated in an inpatient setting under medical supervision. The treatment program consisted of a short prefasting period (approximately 2 to 3 days on average) during which food consumption was limited to fruits and vegetables, followed by medically supervised water-only fasting (approximately 10 to 11 days on average) and a refeeding period (approximately 6 to 7 days on average) introducing a low-fat, low-sodium, vegan diet.


Almost 90% of the subjects achieved blood pressure less than 140/90 mm Hg by the end of the treatment program. The average reduction in blood pressure was 37/13 mm Hg, with the greatest decrease being observed for subjects with the most severe hypertension. Patients with stage 3 hypertension (those with systolic blood pressure greater than 180 mg Hg, diastolic blood pressure greater than 110 mg Hg, or both) had an average reduction of 60/17 mm Hg at the conclusion of treatment. All of the subjects who were taking antihypertensive medication at entry (6.3% of the total sample) successfully discontinued the use of medication.


Medically supervised water-only fasting appears to be a safe and effective means of normalizing blood pressure and may assist in motivating health-promoting diet and lifestyle changes.
A reduction of 37/13?! That's amazing! Everyone talks about how salt causes high blood pressure. But the truth is that reducing salt in one's diet only brings down the systolic (first) bp number by about 3-5 points. That's not nearly enough for me.

So I decided to give fasting a shot. Alas, in Medellin, Colombia (where I did this) it is not easy to find a blood pressure cuff, so I was not able to test my bp before and after.

I began by just committing to fasting for a day or two, but it was going pretty well after two days so I decided to keep going. I found a nice hotel with good wifi for $45/night and re-started my old Netflix membership. For me to resist the temptations of food and drink I need to lock myself into a comfortable place away from the demons alcohol and sugar and greasy, fried Colombian empanadas.

I ate zero food and drank only water from Saturday evening to Thursday morning. I watched a lot of Netflix and rested mostly, taking a nice long walk each day. One benefit of fasting is that the time allows your body to heal and focus on things other than digesting food.

On Day 2 I quit taking my bp pills and on Day 3 I realized that was a good idea because I was feeling a little faint when I would stand up -- a sign of low blood pressure. My doctor told me that feeling faint regularly while taking the pills would mean that I could stop taking the pills. I do not want to be taking blood pressure medication for the next 50 years.

The morning of Day 5, though, I think my blood sugar was also getting quite low. I wasn't feeling good and as I did more research I realized that everyone says a fast of more than 3 days should be accompanied by a physician or at least access to measurements of vitals like bp and blood sugar. As I walked past the free hotel breakfast I noticed it was the most extensive free hotel/hostel breakfast I had seen in months! So I dove in.

My eyes were bigger than my stomach, though, and I didn't yet realize the importance of slowly weening oneself off the fast and back onto solid food. I ate too much granola/yogurt when my body really just wanted fruits and vegetables that are high in water content. Lesson learned.

Today I'm on my second day of recovery and feeling great.

During the five days I rarely felt hungry. Once or twice each day my stomach would grumble. I'd just take a big drink of water and was fine.

Part of the benefit of a fast is mental training. I'm a stronger, more resilient person now because I realize that every time my stomach grumbles I don't have to cram something into it. Over the years I've learned that when I get hungry I really only need a banana or an apple to curb the hunger. In my youth I would eat a huge meal of mostly unhealthy food every time I was hungry. It only took me forty-some years to figure this out.


  1. Fasting definitely reduced my blood pressure. However, I'm not sure by how much or for how long it will stay at this level.
  2. Fasting is uncommon among people I know, but cutting edge science is learning more about the benefits.
  3. After this positive experience, I want to do it again in 6 months or so, but do it with at least a blood pressure cuff handy so I can gauge my actual results.
  4. Benefits of fasting include improvements in:
    1. Hypertension/high blood pressure
    2. Diabetes (type 2)
    3. Anxiety
    4. Depression
    5. Weight loss
    6. Cancer risk
    7. ...and more
Curious? Want to learn more? Here are some places to start.


Ann Vinciguerra said...

Nice work Kirk. I did a three day juice fast during my Jackson Hole days (It was the thing to do in spring mud season) and it just about killed me. Maybe I should try again with some of your tips.

Kirk Ahlberg said...

Ann: if you haven't already done so, start with occasional 24-hour fasts. Those helped me get used to the idea of not eating.