The Powerful Longevity Benefits of Fasting

I’m sure at this point all of us have heard of “intermittent fasting,” which is having a serious moment.  And it deserves a moment, because the health benefits of fasting are incredible, and rooted in thousands of years of culture and experience.

Up until the 1970s, which is about when this country’s obesity epidemic started (thank you fast food, frozen dinners, and packaged snacks), fasting was kind of a way of life.  Until that time, people generally ate at the three prescribed times of day, and while their meal choices may not have been ideal, they weren’t shoveling calories into the hatch all day long.  If we look at our ancestors, they were busy taking care of their farms, or often doing other physically demanding work, and had no access to bags of chips.  They ate maybe three times a day, and sometimes just two, because working through meals was often necessary.  And when they did eat, it was close to the ground—vegetables, fruits, and grains, either from their own land or grown locally, and maybe meat or dairy, but more sparingly. 

Compare that to today, the era of “convenience food,” in which people eat not just three times a day, but are able to snack all day, and into the night (mindlessly in front of the tv).  And not on locally grown produce, but on “foods” that come in packages and are made primarily of chemicals and preservatives.  So not only are we consuming far beyond what humans consumed for thousands of years, but we are consuming fake food.  Moreover, eating is no longer considered a sacred ritual to be enjoyed with family and friends.  It’s, again, a matter of convenience.  How often do you eat standing up while doing something else, or at a computer, or in the car?  Meals used to be a meaningful time for coming together, saying grace, and giving thanks for the blessings on the table.  Now it’s just too easy to grab a burger from the drive-through and call it a day.  All the “convenience” era has done for us is make it convenient to make poor choices for the health of our bodies and minds.

Does this make you sad? It makes me so sad. 

Putting aside the unhealthy food choices for now, the all-day-eating in itself is robbing us of years and years of life.  As renowned researcher and scientist David Sinclair has said:

“If there is one piece of advice I can offer, one surefire way to stay healthy longer, one thing you can do to maximize your lifespan right now, it’s this: eat less.”  David Sinclair, Lifespan.

Caloric restriction has been studied for decades, and the idea is that you eat enough to achieve proper nutrition (that’s key), but not much more, which activates your survival circuit, “telling longevity genes to do what they have been doing since primordial times: boost cellular defenses, keep organisms alive during times of adversity, ward off disease and deterioration, minimize epigenetic change, and slow down aging.”  Lifespan, p. 91.  Calorie restriction not only adds years to your lifespan, but years to your healthspan.  Okinawans were studied in 1978 and found to consume 20% fewer calories than adults on the mainland, and they not only lived longer than their counterparts, but were found to have significantly less disease.

But calorie restriction is hard, and the great thing is, you don’t have to calorie restrict all the time to reap the benefits it offers.  This is where intermittent fasting comes in.  As discussed in more depth in Lifespan, for populations in the world where fasting is a way of life, like in Ikaria, Greece, popularly called “the island where people forget to die,” it is found that fasting is significantly correlated with longevity.  There are a lot of reasons for this, including that fasting results in lower levels of a hormone called insulin-like growth factor-1 (IGF-1), which is linked to lower rates of disease and death.  Fasting also gives your body the break it needs to stop digesting and focus on healing.  And, as mentioned above, a certain level of stress (going without food) activates our bodies’ longevity circuits.

None of this means we shouldn’t be eating plenty of nutritious foods, but instead that we should be changing how much and when we eat.  There are different ways to do this, and it seems from the research that any amount of fasting is associated with positive outcomes.  Here are three methods discussed in Lifespan that are tried and true:

1.  The 16:8 method – this is a method in which you consume food for an 8-hour window (maybe 12:00-8:00), and fast for the remaining 16 hours of the day.  You could also tweak this by shifting the window, or making it a bit shorter so you eat in a 10-hour window and still get 14 hours of fasting.  The idea is to give your body a significant portion of the day to fast.

2.  The 5:2 method – this method focuses on changing your eating habits for 5 days per week, during which you eat 75% of your normal caloric intake.  This method seems like it could work for people who dutifully count calories (which is not me).

3.  Eat-Stop-Eat method – this method is more extreme, and suggests skipping eating entirely for two days per week.  Or it could be modified so you fast for a certain number of days per month. 

And beyond these methods, one way to calorie restrict is simply to stop all the snacking!  And I have to admit, I love snacking.  Thankfully, I typically snack on healthy foods like fruits, veggies and nuts, but I definitely pop in handfuls of cheddar bunnies here and there when I’m making snacks for my kids.  And is that terrible? No.  But, when I think about calorie restriction adding potential years to my life, it makes me think that maybe I limit that kind of snacking to a couple days per week, and am more conscious the rest of the week.  Currently, I’m making a concerted effort to have no snacks after dinner, so I’m limiting my food intake window to about 10 hours (8:00-6:00).  Will I do this even on Friday movie night?  No, probably not.  But, thankfully, perfection isn’t required.  And I think this is what trips people up with respect to any healthy habit—if I can’t do it perfectly, I just shouldn’t bother.  No!  Do what you can! Making healthy choices, around food or any other area of life, is an accumulation of goodness.  It all adds up.

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Ultimately, making the easy, convenient choice isn’t always the right one.  And in today’s consumer-focused world of more, more, more, this certainly holds true.  Abstinence doesn’t have to be associated with total deprivation, especially if it’s intermittent.  We should all harken back to our ancestors and emulate their tradition of enjoying family meals, a few times a day, savoring locally-grown food.  We get one (amazing and miraculous) body. Let’s do our best to treat it right.