Benefits of Fasting
If you’re wondering why everyone is talking about fasting lately, it’s because the science that supports it being beneficial to our health, fitness, and mood just keeps getting stronger and stronger. In this article, we’ll walk you through the MovementLink LIfestyle protocols with time-restricted eating and prolonged fasts (which are both sometimes called intermittent fasting), why we implement these into our lifestyle, and tips on how we do it. At the bottom of the page, we’ll add links that will help you deep dive into the topic with some of our favorite scientists.
The MovementLink Lifestyle Fasting Protocols:
We consume all our daily calories within a 6-8 hour Time Restricted Eating Window (also sometimes called intermittent fasting).
We include a Prolonged Fast, 72 hours in length, 1-4 times a year (also called intermittent fasting).
We don’t consider drinking water, tea, black coffee, or electrolytes as breaking our fasted states.
Before we jump in, let’s start with a way of thinking about this that has helped drive our decision making. We are either in a fed state or a fasted state and there are different levels of hormones and genes that are turned off or on depending on which of these two states we are in. In a fed state, our body is typically in cell growth mode and when we are in a fasted state our body is typically in cell repair mode. Both of these modes are important and we want to be sure our lifestyle includes both and an eating window helps us optimize the amounts of time we spend in each. So, when we are thinking of time restricted eating, we like to think of it as being strategic about when and how long we spend in fed and fasted states. In this article we are going to focus on the benefits of our strategic, fasted states.
Time Restricted Eating
The first consideration that we tend to center a lot of things around is our circadian rhythm. Light is the number one influencer of our body’s internal clocks, but when we eat is the number two factor that determines when our body preps us for sleep and when it makes us awake. By “feeding” our body the correct information about what time of day it is, our body can better lend itself to being maximally awake or maximally asleep. Another circadian rhythm benefit is that our gut’s enzymes typically pack it in for the day after having been active for around 12 hours. If we are consuming calories outside of a natural window, not only does our body get confused about what time of day it is, but your body’s digestion is not geared up to handle food well outside of the eating window. It’s not just what you eat, it’s when you eat. A fun side benefit of the impact on our internal clocks is that when we are are consistent with our eating windows, we can actually temporarily shift them by an hour or two and trick our body to do what we need it to do: if that’s going to sleep earlier one night, staying up later, or just wanting to negate some of the effects of jetlag.
Additionally, because we have these longer periods without new sources of carbohydrates and sugars, which are the fast burning fuel sources, our bodies have to become more metabolically flexible, which basically means that our body is better at being able to use energy stored in fat cells as fuel. Not only do these longer periods of reduced carbohydrate intake also improve blood sugar levels and help cells stay sensitive to insulin, being metabolically flexible makes our energy levels much more stable and our body must be able to tap into the energy in our fat cells if we are looking to lose body fat.
While fasting, levels of human growth hormone are also elevated. This isn’t just cool for those looking to build muscle right now, this is important because as we age, growth hormone decreases making it harder and harder to maintain muscle mass and lose body fat which is extremely important as we age. We don’t know any 90 year olds who wish they had less muscle mass, so everyone needs a good buffer zone of muscle mass, so they have adequate amounts to continue being active in their last decade.
For those who are interested in reducing body fat, time-restricted eating can be an amazing way, along with our other MovementLink Lifestyle nutritional protocols, time restricted eating has been shown to reduce body fat, even without calorie counting; probably because it removes a lot of snacking and caloric drinks, especially late-night, which adds calories and get you out of your natural circadian rhythm impacting sleep.
What about lifespan? Well, time-restricted eating promotes a decrease in mTOR, an increase in AMPK, and sirtuin gene activation. I’ll refer you to Dr. David Sinclair (video at the bottom of the article) for the details, but, in short, fasting mimics tough times which trigger genetic pathways that support being younger longer.
Maybe the coolest sounding benefit is autophagy, where your body will prioritize cannibalizing cancerous, dead, and senescent cells before any healthy cells are touched. Effectively, autophagy is a process that cleans house and makes way for new, healthy cells. There seems to be some autophagy that happens with an eating window, especially if you can get into a fasted state while you are sleeping, but autophagy really kicks into high gear at around the 3 day mark - which is where our prolonged fasts come in.
Prolonged Fasts
Like we said above, there is one major thing we are after with our prolonged fasts and that is autophagy. There is some fasted sleep autophagy that occurs with time restricted eating, but at about the 3-ish day mark, our body really goes hard into the clean up and protection mode. AS cells replicate and age, their DNA and their epigenome (their DNA reader) gets damaged, mutating the cell. As genes get turned on and off that are not supposed to, cells stop doing their job like they are supposed to. The body has a way of identifying these cells and shutting them down, so that most every cell that has an issue gets shut down before it can do too much damage. But, these damaged cells, called senescent cells, cause inflammation, which in turn speeds up the aging process, and clearing these cells out has great health implications. Autophagy is the body prioritizing cannibalizing these senescent cells and other damaged cells for energy and then when we re-feed with quality food, our body can build back stronger.
How do we implement our Eating Window and Prolonged Fasts?
We commit to a Daily Time-Restricted Eating Window
We choose a duration, around 6-8 hours.
We then select our start and end time, but under these conditions:
We choose a window that can be consistent day-to-day (understanding we don’t have to be perfect).
We make the start time at least 1 hour after waking up.
We make the end time at least 3 hours before bed.
If possible, we eat our first meal before we workout. This is not because we should not workout fasted - we think that is fine and we happen to do that a lot on weekends when we workout earlier than we do on weekdays. This is for blood sugar regulation. There are two times that our body does a better job of handling higher carbohydrate meals without spiking blood sugar, the first meal of the day and the first meal after a workout. It is not necessary, but an additional advantage to have two meals each day for which our body can more easily clear blood sugar.
Within our eating window, we eat 3 meals, spaced at least 2 hours apart.
This comes from our MovementLink Lifestyle Nutrition side of things, but it's because we try to center our diet around eating, each day, somewhere between 0.7 to 1g of protein per pound of the body weight we’d like to weigh. Protein, unlike fat and carbohydrates, isn’t really stored in the body as protein, so if you cannot absorb it right away, your body doesn’t really use it to rebuild your body. There is also only so much protein you can absorb per sitting (about .33g of protein per lb of bodyweight). Because we care about growing and maintaining muscle mass for many reasons associated with quality of life and since we can only absorb about ⅓ of the total amount we are looking for in a day during each sitting, the math works out for us to shoot for 3 meals each day, each with ~0.25-0.33g of protein per pound of bodyweight.
If you don’t think 6 hours is long enough to eat 4 meals, here’s how you may space it out example:
1 PM - Meal
4 PM - Meal (Smaller depending on goals)
7 PM - Meal
We’ve seen people overeat (although it was just temporarily) on a shorter window because they were very hungry going into their first meal. So, we plan our 6-8 hour eating window, but then start with a 12 hour window and gradually shrink it down each week.
Once a quarter, we implement a prolonged, 72 hour fast. We have water, tea or black coffee, and some electrolytes, but that’s it. We try not to plan anything with high stress or do any extremely fatiguing workouts, but understand that there is never a perfect time to schedule it. We stay active and can even workout a bit,but keep it on the easier side - it’s just 3 days. The goal of these 3 days is not workout gains, it’s autophagy and resiliency.
A few considerations for athletic performance:
Now this information may sound exactly counter to everything you have ever heard about eating and training, so we’ll discuss this a bit more, but first let’s look at it from this perspective: most diet advice linked to training is from professional bodybuilders, powerlifters, and other professional athletes whose only goal is performance. The MovementLink Lifestyle is about extreme health and fitness, so while they may be willing to sacrifice long-term health to peak right now, we are not. But, we do want an extremely high level of fitness, so let’s look at a few things to consider:
When looking for the bro-science window of gains, research shows that there is no muscle building difference between consuming protein right after a workout vs getting the same total amount of protein within the day. This is likely because muscle protein synthesis occurs for up to a couple of days, so muscles are ready to recover as long as they are getting their fuel eventually.
Now, if you are participating in two-a-day workout programs, at a competition or event, or just doing multiple high efforts within the same day, eating carbohydrate and protein after a workout can have a major benefit to recovery for your next session. In scenarios where this is a consistent thing, you’ll want to work your eating window around your training schedule to be sure you are eating soon after your first workout.
What about eating 6 meals a day. I’ve heard that’s healthy? Well this is a strategy that seems to be popular with the powerlifters because it is a great strategy to maximize protein intake. Because you can only absorb so much protein in one sitting, to maximize your protein intake during the day, you have to spread it out across as many meals a day as possible. Some will even wake up in the middle of the night to eat. When balancing performance and healthspan, maximal protein intake is not the goal. We are fans of protein, we center our diets around it, but there’s a balancing act that needs to be played since we are playing the long game. We eat enough protein to gain and maintain muscle mass, but are trying to find the minimally effective dose because high protein deactivates longevity pathways.
Deep Dive with our Favorite Experts:
Article: Chris Kresser - Intermittent Fasting: The Science Behind the Trend