If you are like most people, then you’ve heard the buzz recently on fasting but don’t quite understand the process.  If fasting is nothing more than not eating food, you could be left wondering why anyone would think this concept is a good idea or why it has developed a large, trendy following.  However, the science of fasting is starting to come to light and the health benefits are being elucidated.  It seems like this ancient ritual has hit a modern day stride.
Fasting has been part of my religious tradition for millennia, but, I admit, I have rarely practiced it.  As an evangelical Christian of the reformed tradition, I have always viewed fasting as one of those extra things you could do but it wasn’t required for salvific faith.  So over the years I would engage in types of fasting such as abstinence from particular foods during the Lenten season but never with a mindset that it might be beneficial for my physical body or that it would be very easy.  In fact, it was supposed to be hard.  I viewed it as solely an act of self-denial that was meant to sharpen my appreciation and understanding of Christ’s self-denial and sacrifice.  For me, giving up food was always a challenge.

This article from Science does a good job a describing the four basic types of fasting methods that are commonly researched.  In my practice, I typically only utilize two of them for myself and my patients.  I encourage time restricted feeding (TRF or sometimes called time restricted eating, TRE) for virtually all of my patients from day one.  As patients progress or if they have more metabolic challenges to overcome like diabetes, I will layer on intermittent fasting (IF) to their therapy plan.  Of note, the last two patients I’ve had who reversed their diabetes utilized both TRE and IF regularly.
The other two types of fasting are not as well utilized in my practice for separate reasons.  Calorie restriction has long been the cornerstone of weight loss therapies however we also have a long history of poor success with these programs.  It turns out that humans have a really hard time not eating enough food indefinitely.  Go figure.  These programs often fail because our lack of willpower to deny ourselves something we need to survive for an indeterminate time.  That is why fasting on an intermittent basis works.  We can deny ourselves for shorter periods of times, even a few days in a row, without the same psychological stress of long term food denial.  So, while calorie restriction has its scientific success stories, from a practical standpoint, I don’t find it useful in my practice.
The fasting-mimicking diet is a fascinating plan which I have yet to incorporate in large scale to my practice.  The 5 day time frame of very little food intake is a big step for many patients.  The results are impressive in animal models and the regenerative powers of such a program are hard to ignore.  I hope as our experience in fasting grows that I’ll be able to incorporate this into the appropriate patient’s therapeutic strategy.
Now, let’s go back to the two types of fasting protocols I regularly prescribe.  Time restricted eating is a very simple program where patients develop a diurnal pattern of eating for a set number of hours followed by abstinence of all food and drink save water for the remainder of there 24 hour cycle.  In several observational studies on eating schedules it has been found that many people eat some type of food every few hours from the time they get up to right before they go to bed.  That accounts for up to 16 hrs out of every 24 that we’re ingesting something.  The 7-8 hour window of bedtime and sleep is the only time they don’t consume food.
F3.largeWith TRE that 7-8 hour window of fasting is stretched so that the minimum fasting time to be considered TRE is about 12 hours.  Biologically, many unique activities begin to occur after 12 hours of fasting that don’t occur while we are in the fed state.  As the duration of fasting grows, the cellular changes continue to expand such that after 13-14 hours of fasting several thousand fasting-only cellular activities are occurring.  If we never reach this threshold, then we can never see the effects.
For most all of my patients, I recommend TRE of about 12 hours as a basic step.  It’s not too hard either.  Most patients have to decide not to eat again after dinner by avoiding their bedtime snack.  Breakfast may need to be pushed back to sometime other than upon awakening in the morning.  Otherwise, many patients don’t require much adaptation.  This type of fasting doesn’t require much in the way of nutrient change either.  Therefore, as patients learn to change their nutrition some simple changes in timing can be incorporated too.
As patients progress in our dietary education program and adopt our whole food, low carbohydrate, high fat approach I encourage them to incorporate intermittent fasting (IF) into their weekly schedule.  By the way, the graphic above lists the low carb, high fat (LCHF) approach as ‘obesogenic’.  This is blatantly wrong on several levels but I won’t address it in this post.  Not coincidentally, as this nutrition program takes root in a person’s daily life, their body begins to normalize hormonal production of insulin, grehlin, and leptin.  These regulatory hormones help us shed or store weight and strongly influence the hunger sensation.  Normalization allows for weight loss which prompts reduced hunger.   Consider this, if stored weight in a fat cell is being released into the blood stream and your body is now tuned to utilize that for fuel, wouldn’t the need for finding food to ingest lessen?  It does, dramatically.
As patients adopt and adapt to the whole food, LCHF plan, they naturally adopt varying degrees of TRE and IF.  They often forget to eat.  They get busy working on something and without the hunger drive to kick in they opt to work through the day instead of stopping for lunch.  It’s not that their mechanisms are broken, it’s just that their fuel tanks are so much bigger now.  They don’t run out nearly as easily.
As this progresses, I encourage my patients to find one 24 hour stretch of time that they can fast.  Often the best time to do this is the roughly 24 hours that begins after a dinner meal and ends prior to the next meal.  By skipping after dinner eating and snacks, we can wake up with 10-12 hours of fasting already out of the way.  We’re well into the cellular machinery that makes fasting easier.  Continuing this until the dinner meal will be less challenging than you think.F4.large
I’ve talked a lot about the types of fasting I use in my practice and touched slightly on how to initiate them.  However, there are many factors involved which I obviously can’t cover in a blog post.  Please don’t take this as specific medical advice for you in your situation as many other factors need to be considered.  If you’re on medications that are influenced by fasting, you’ll need advice on how to adjust them.  If one fails to appropriately adjust their insulin, for instance, it could be disastrous or even deadly for someone attempting to fast.
If you’re interested in adding fasting to your dietary regimen, then give me a call.  As a DPC patient you already have my phone number and email so feel free to contact me anytime.  The DPC dietician, Carly Slagle, and I will guide you through a program that makes sense and allows you to hit your health goals.  If you aren’t a member of our DPC program, then consider signing up.  It’s hard to imagine just how healthy you can be until you start to see the progress that so quickly occurs with good nutrition.