Fasting #

Why fast? #

Alternate day fasting and periodic prolonged fasting (2-5 days of fasting once every 1-4 months) seem to have a protective effect against many (all?) age related diseases, suggesting that it may also slow the aging process itself. See this review for a good summary of the research: Intermittent and periodic fasting, longevity and disease.

One eye-catching result is this study, where rats lives ~80% longer when on an alternate day fasting regimine.

My Experiences #

Fasting Mimicking Diet - January 2020 #

I started getting interested in fasting after reading The Longevity Diet by Valter Longo. Based on the information in the book, it seemed like fasting provided some easily attainable health benefits, if making it a habit wasn’t too disruptive to my life. In Longo’s own words, the diet is:

Day 1

1,100 calories

• 500 calories from complex carbohydrates (vegetables such as broccoli, tomatoes, carrots, pumpkin, mushrooms, etc.)
• 500 calories from healthy fats (nuts, olive oil)
• 1 multivitamin and mineral supplement
• 1 omega-3/omega-6 supplement
• Sugarless tea (up to 3 to 4 cups per day)
• 25 grams of plant-based protein, mainly from nuts
• Unlimited water

Days 2–5

800 calories

• 400 calories from complex carbohydrates (vegetables such as broccoli, tomatoes, carrots, pumpkin, mushrooms, etc.)
• 400 calories from healthy fats (nuts, olive oil)
• 1 multivitamin and mineral supplement
• 1 omega-3/omega-6 supplement
• Sugarless tea (up to 3 to 4 cups per day)
• Unlimited water

The above components can be divided between breakfast, lunch, and dinner, or they can be taken as two meals and a snack.

Day 6

Transition diet

For 24 hours following the end of the five-day FMD, patients should follow a diet based on complex carbohydrates (vegetables, cereals, pasta, rice, bread, fruit, etc.), and minimize the consumption of fish, meat, saturated fats, pastries, cheeses, milk, etc.

My first FMD experiment happened shortly after reading the book. I attempted a 5 day DIY-Fasting Mimicking Diet (FMD) as described above.

I used eatthismuch to pre-plan my meals for the FMD. I think it would have been much harder for me to adhere to the diet if I did not do this. Here is what I ate:

If my memory serves me well, I remember feeling quite good during my fast, which some minor headaches on day 2-3. I did this during my vacation from work, and I don’t remember working intensely on any particular project during this time, so I wouldn’t consider this a “stress test” of the diet.

Water Only Fast - December 2020 #

Further exposure to fasting proponents, especially Peter Attia (via e.g. his podcast with Eileen White, made me think about the simpler prospect of doing a water only fast. I finally attempted this during a work week in December 2020. My schedule looked like:

• Tuesday:
  • Large Spinach, Tomato, Olive Oil, Vinegar, Italian Seasoning Salad for lunch
  • Some walnuts for dinner
• Wednesday:
  • Only water
• Thursday:
  • 4ish servings of Better Than Bouillion stock concentrate (in water) + steak seasoning
• Friday:
  • 4ish servings of Better Than Bouillion stock concentrate + potassium containing spice mix

Here are the stock ingredients I used:

I felt surprisingly normal during my fast. Especially when exercising - I went on my normal ~3 mile run on Thursday with 25 * 2 sets of push ups and 10 * 3 sets of pull ups interspersed and felt actually better than I normally do. Perhaps this was because of the water/glycogen weight I lost at the start of the fast (~5 lbs, 190lbs -> 185lbs).

There were times when I felt a bit lightheaded also during the fast, but never too seriously. This may have been a bit psychological, since I knew I was fasting.

One thing I also noticed was it was even harder than normal for me to keep warm in my ~65F apartment, especially when sleeping. The Wed-Thurs night I did not sleep very well because of this. Any kind of draft under the blankets was very noticeable and interrupted my sleep. I wearing light sweatpants and a shirt the next night helped a lot (usually I sleep close to naked). On the whole, I would say my sleep was worse during the fast than normal.

I did notice some tingling in my arms/legs, especially when putting a acute force on them. For instance, when doing push-ups, my hands would start tingling. And when putting my ankle on my knee when sitting, it would tingle strongly. Apparently, this is expected. This was reduced when I starting drinking broth.

One thing that I also definitely noticed during my fast was a shift in my brain activity. I felt much more “on” than usual - I had a consistant motivation to be busy in one way or another. However, I also felt a bit more impatient. If a task I was busy doing started to stall, I would eagerly try to shift to another task, or even multitask. This was good for getting lots done, but not as helpful for cracking a difficult problem (e.g. debugging a computer program) I could use this feature of fasting in the future if I need to be particularly productive in this way.

Water Only Fast - June 2022 #

I collected some data during this fast which can be seen at https://docs.google.com/spreadsheets/d/1gp4n59h3I0r1DnM8NQq4ISGtDY9ameoDuqInhsv2WYI/edit#gid=0.

Categories: Health And Longevity

Backlinks: Food,