Seven years ago everybody started touting the benefits of a low carbohydrate diet.  Four years ago the world dropped their carbs even further and everyone went Keto.  Today I can’t seem to open my phone without the words ‘intermittent fasting’ showing up in a news feed, Tweet, or Podcast.

One of the first articles I noticed was how Jimmy Kimmel lost 25 pounds.  He looks really good and has been doing the 5:2 diet where he eats whatever he wants for 5 days and on Monday and Tuesday he restricts his calories to around 500 per day.

The next celebrity-faster I came across was Terry Crews.  In the short video below he talks about how he fasts each day for 16 hours and eats during an eight hour feeding window.  He is very happy with his results after adhering to this regimen for over five years.

A few weeks ago, I learned that Jack Dorsey, the founder and CEO of Twitter, has been having success with intermittent fasting. He only eats dinner during weekdays and occasionally will fast all weekend.

Why are these smart, successful people purposely depriving themselves?  Since there isn’t any money to be made by telling people not to eat, it is going to be a long time before we see a significant randomized controlled trial that proves the benefits of intermittent fasting.  There is a lot of anecdotal evidence from trustworthy people and doctors who have tried their own N of 1 experiments.  I think fasting has become popular for the following three reasons: better cognitive performance, weight loss, and improved health.

Improved Cognitive Performance

In the ultra-competitive world of Silicon Valley, fasting has become popular because many people report sharper brain function and having more energy while fasting.  This could be because your brain and body are running on ketones instead of running on glucose.  If you haven’t eaten in 16 to 24 hours (or more), your body has likely exhausted its store of glucose and you are burning your stored body fat for fuel.  A lot of people report they feel mentally sharper while in ketosis.  Since this is obviously subjective, the only way to know if YOU will feel better in ketosis is to give intermittent fasting a try.

From an evolutionary standpoint, it makes a lot of sense that when you are hungry, your brain and senses would be sharper to help you locate your next meal.  Dr. Jason Fung, head of Intensive Dietary Management, recommends exercising while fasting.  Anecdotally, many people report that their work outs are better in a fasted state.  I tried playing basketball for two hours after eight days without food and I surprisingly felt just fine.

I tried a three day fast, an eight day fast, and I starting eating every other day.  I eventually found the Warrior Diet works best for me and I have been doing it for about a month.  I fast for about 20 hours per day and only eat dinner.  This has saved me an hour a day by not eating lunch and has helped me be more productive at work.  My personal experience aligns with many of the stories you read about on WeFa.st, a site promoting the benefits of intermittent fasting.

Weight Loss

While many people would fast just for better brain function and higher energy levels, it is also an effective method for losing weight: particularly for people who struggle on other diets.  One of the reasons I think it works for me is that I have trouble controlling my portions once I start eating.  When I would allow myself two meals a day (I haven’t eaten breakfast in years), I would go full on pig-mode twice per day.  Since I now only eat dinner, I am eating less calories.

Many people find it easier to restrict WHEN they eat than to restrict WHAT they eat.  I don’t think we fully understand the science, but there are a lot of people achieving great results with intermittent fasting while continuing to eat what they want.  I personally have been able to eat more carbohydrates while intermittent fasting, but I still put on weight if I eat really bad food.  A quick search on Google leads you to the following success stories:

Dr. Kevin Gendreau lost 125 pounds

Dr. Tro Kalayjian lost 150 pounds

168 Success Stories and Counting

There is even a popular Instagram channel where you can watch videos of Blake Horton eat insane amounts of food while staying thin with his intermittent fasting routine.  While I find videos like the one below to be entertaining, I suspect the long term effects of eating that many processed carbs is not good for you.  Professor Tim Noakes has run more than 70 marathons and used to advocate carb-loading before he developed type two diabetes later in life.  My personal belief is that eating a whole-foods-based low-carbohydrate-diet while intermittently fasting is optimal.

https://www.instagram.com/p/Bv1wdPSHHFb/?utm_source=ig_web_button_share_sheet

Since there isn’t a lot of profit in telling people to only eat once per day, don’t expect to see a multi-million dollar study that definitively shows all of the health benefits of fasting.  There are hundreds of people that have shared their successes on the internet.  Either they are all part of a grand conspiracy or there is something to this.

Improved Health

The last reason everyone seems to be intermittent fasting these days is to get healthier and live longer.  If you find yourself learning more about fasting, it will not take you long to discover Canadian Doctor, Jason Fung, who runs the Intensive Dietary Management Program.  Their website is loaded with testimonials of people reversing their type two diabetes and fatty liver disease by following a low-carb diet and intermittent fasting.  Fung literally wrote the book on fasting and his clinic offers online coaching to help people regain their health.  I didn’t think an entire book telling you not to eat would be very interesting, but after my wife bought it, I decided to read it and I am glad I did.

In addition to battling diabetes and fatty liver, this article has links to several academic papers that claim intermittent fasting can help you:

reduce inflammation
improve pancreatic function
reduce your risk of heart disease
increase human growth hormone
regulate gherlin (the hunger hormone)
make you more insulin sensitive

The main health benefit of intermittent fasting seems to come from autophagy (self-to eat). This video does a good job explaining the complicated biology that goes into your body processing (eating) your damaged cells to repair itself.

While Angus Barbieri was able to go without food for 382 days and lost 276 pounds, that is probably not what you need to try.  If I have peaked your interest in anyway, I suggest clicking on some of the links above to learn more about fasting.  Eating only dinner is working really well for me and my wife, but it hasn’t been that long.  If you decide to give it a try make sure you are under a doctor’s supervision.