Something I hear all too often is the belief that fasting is dangerous, "bad for you" and confusing. With all the documented longevity and fat loss benefits one can get from a full fast, it's disheartening (to say the least) to see people write it off completely.
In this long form article, I'm diving WAY DEEP into all things fasting. We'll discuss extreme caloric restriction (harmful) vs. fasting (healthy), autophagy and Apoptosis (both good), and the type of people that can benefit the most from incorporating fasting into their healthy lifestyle (hint: almost everyone).
Let's get started with Caloric Restriction vs. Fasting. The most important thing to remember here: THEY ARE NOT THE SAME.
I can understand why people get confused, especially if you find yourself in the beautiful vortex of the Clovis Academy. One week I'm preaching about how horrible chronic caloric restriction is for your fat loss goals and the next I'm telling you how great it is to stop eating altogether!
I can almost hear your brain scratching itself… Huh?
This entire topic is nuanced. What works well for one person won't work well for others. It's important to play around with these modalities and find out what works for you. The truth is, like most things in health and wellness, it depends. Before you dive into any new protocol ask yourself one critical question: What is the end goal?
So today, I'm here to explain the difference between caloric restriction and full fasting. My goal is to help you make an educated decision about fasting and if it can help you achieve your goals. Beware, I'm going to get a bit geeky about it…
I want to start by dispelling the blatant and ridiculous lie that fasting is harmful to you or somehow "unhealthy." I believe this assumption snuck up on as we gradually started losing trust in our own bodies... and started trusting big food companies. You know, the ones that tell us we need to eat and snack every few hours. God forbid the dreaded energy crash! We started believing we somehow "knew better" than mother nature and tried to prove her wrong. Let me tell you a little secret: you can't outsmart mother nature, stop trying.
Fasting, as a religious practice, goes back thousands and thousands of years. There is not a religion out there that hasn't incorporated some form of fasting into hyper-spiritual practices.
Fasting, as a way of life, is also how we survived for millions of years. Do you think our hunter-gatherer ancestors "stopped for a snack" in the middle of hunting mammoths? Do you think they grabbed a Larabar to "fuel up" before they started the day? Hell no!
They fasted. Each and every day. Naturally. Because they had to. Because they had to hunt everything they ate. And sometimes they went without food for very long periods. And their bodies knew precisely how to handle it!
Okay, okay. I'll get off my soapbox now. Time to get into the science of why caloric restriction is so much different than fasting.
The primary reason chronic caloric restriction is detrimental to your health and fat loss goals is hormones. Our hormones run the entire show, and when we put our bodies in long-term starvation mode, everything gets messed up. I have an entire episode on this very topic, Hormones: Finding the Balance.
A traditional "caloric restriction diet" (the kind you'll get from about every corporate-gym-personal-trainer-fitness-junkie) looks a bit like this: 800-1,200 calories a day, spread out into 5 small meals consisting of lean protein (like dry chicken breasts) and carbohydrates (like 1 cup of brown rice). Sound familiar? And notice something important here: this diet includes ZERO FAT (a macronutrient human beings can't live without).
On a diet like this, you'll lose some weight for the first month or so (as your body tries to figure out what the hell you're doing) and then, without fail, you'll plateau. You'll stop losing weight or, even worse, start gaining it back. Here's why:
As you continue to keep your body in a state of extreme caloric deficit, your hormones adjust to their new reality. With sporadic feeding… with little to no fat consumption, your body freaks out, goes into survival mode and starts hanging onto every fat cell available.
Remember, we need fat to survive. We will literally die without it. And our bodies are brilliant. Therefore, when we experience long periods without receiving any fat and barely enough calories to function, we begin to hold onto energy stores and shut down specific bodily functions to preserve energy. All because the body is operating under the belief system that essential fat will not be delivered any time soon.
The body is genuinely confused here… because it's still receiving food, so it's not "actually" starving. So, the mechanisms of full-blown fasting don't kick in at all. Let's say your BMR was 1,800 calories per day, and you decide to start giving it just 800. The body will adjust to the new environment and, again, shut down certain organ functions to preserve energy! It will lower its own BMR down the 800 you've trained it to get used to. The new BMR is now firmly set at 800 and weight loss completely stalls. If you start eating over 800 calories per day, the weight you initially lost comes back because you're now "technically" eating a caloric surplus! This is outlined wonderfully in "The Biggest Loser Study."
When you're genuinely fasting (not to be confused with a caloric deficit), the body has built-in mechanisms to keep you healthy! For instance, it spikes noradrenaline which holds your BMR at its proper set point, say 1,800 calories. On top of that, during prolonged fasts, Growth Hormone can spike by as much as 300%, which preserves lean muscle tissue and ensures the weight loss you're experiencing comes from body fat! If the body is still burning it's normal 1,800 calories per day, it has to get that energy from somewhere. Where does it get all that energy?! From your stored body fat. The Holy Grail of fat loss. This entire process is, quite literally, the reason the human body stores body fat to begin with. To help us survive in times of food scarcity! Mother nature is a straight-up genius!
Phew, that was important, so I really hope it made sense…
This, in a nutshell, is why chronic caloric restriction doesn't work.
Now, let's get into why fasting does work and is one of the most natural and most beneficial things you can do for your health and fat loss goals.
Insulin is the #1 driver of fat storage. Period. Insulin is a storage hormone, and it is the primary driver of obesity. If you have chronically elevated levels of insulin, odds are, you will become overweight and eventually obese. If you have chronically elevated insulin levels for too long, you will become Type 2 Diabetic.
Insulin levels drop when we are in a fasted state. Insulin levels rise when we are in a fed state. It's about as simple as simple gets.
So what makes insulin levels rise? Food. Most notably, carbohydrates.
Carbohydrates have the most significant impact on blood glucose levels. Insulin is recruited to clear the glucose from the bloodstream and shove it into muscle or fat cells. The more glucose in the blood, the more insulin is released, the more glucose is stored. This is why you often hear people talk about the Glycemic Index. Foods with a high Glycemic Index impact blood sugar and thus insulin levels the most.
I gave you this short lesson to drive the point home that lowering blood sugar and insulin is the key to sustainable fat loss. You can achieve this by carefully selecting the foods that you eat. This is always a good idea. That's why I started a Paleo nutrition company, to help people navigate their food choices and thrive on a diet filled with nutrient-dense, unprocessed, whole foods. But that brings me to my next point...
Even if you carefully select each and every food item that you consume, the results will not be nearly as robust as full-blown fasting. Fasting is the single most effective way to reduce insulin and blood glucose levels in the body rapidly. The results can sometimes be hard to believe! But again, it is essential to remember that fasting is a therapeutic modality and it must be used responsibly! Is it powerful and beneficial to health? Yes, generally speaking. Can it be completely overdone and lead to negative consequences. Yes, without a doubt. So be responsible!
Autophagy and Apoptosis… What the hell?!
Now I want to get a little nerdy on you and talk a bit more about the two most important aspects of fasting: Autophagy and Apoptosis.
Yes, both concepts involved a sort of "cell destruction" process, but at their core, their mechanisms of action are entirely different. Autophagy and Apoptosis are vital components of long term health. They both assist in disease prevention and increase longevity. That said, it's critical to understand what these functions are and how they work.
That's why I'm here... to let you in on the beautiful benefits of cell destruction! Don't worry, it's not that complicated, and it's not as scary as it sounds. As an added bonus, I'll even give you the insider tips on how to use these tools to optimize your health and speed up fat loss!
Okay, let's dive in.
We'll start with autophagy. The word "autophagy" is defined as, "self-eating."
Auto = “self”
Phage = "to eat"
Autophagy is a process occurring in our cells that can be characterized as a "detox." A clean-out or a replacement of certain parts of the cell. Autophagy does not destroy the whole cell. Instead, it picks at the parts of the cell that aren't working so well, targets them, and destroys them. In a sense, autophagy occurs when your body eats itself. Kinda weird, right? The good news is, the cell gets a makeover! The old, broken down parts are replaced with shiny new parts! Think of autophagy as a NASCAR pit crew for your cells.
Naomi Whittel, the author of Glow15, uses the analogy of a kitchen to explain autophagy at its finest (and not so finest):
"Think of your body as a kitchen. After making a meal, you clean up the counter, throw away the leftovers, and recycle some of the food. The next day, you have a clean kitchen. This is autophagy doing its thing in your body, and doing it well.
Now think of the same scenario, but you're older and not as efficient. After making your meal, you leave remnants on the counter. Some of it gets into the garbage, some of it doesn't. They linger on the counter, garbage, and recycling bin. They never make it out the door to the dumpster, and toxic waste starts to build up in your kitchen. There's food fermentation on the floor and all kinds of nasty smells wafting out the door. Due to the onslaught of pollutants and toxins, you're having a hard time keeping up with the daily grime. This scenario resembles autophagy that isn't working as well as it should."
It would take me a book or two to describe to you all the benefits of autophagy for long term health, so we'll fast forward... I go into more in-depth info in my podcast episode, "Fasting Facts: From Fat Loss to Longevity." If you want to geek out on this stuff, that's the episode for you!
At its core, autophagy metabolizes (uses for energy) proteins (the makeup of our cells). It selects specific proteins that are old and/ or malfunctioning by destroying them.
Now we'll get into Apoptosis, and how it differs from autophagy.
Apoptosis is actual cell death. It is a form of programmed (regulated) cell death that allows cells to self-destruct. The cell self-destructs without causing any harm to its surrounding environment. Apoptosis is a clean and tidy process of your cell breaking down its internal components (proteins and chromosomes) and disposing of them in a way that allows surrounding cells to use the "left-overs" for their own benefit.
Literally defined, Apoptosis means "falling away."
Apop = "away" (or, from)
Tosis = "falling"
Apoptosis is a very healthy, necessary process of the human body. It "keeps things clean" by disposing of pre-cancerous cells, infected cells, and cells with growth abnormalities. Removing these cells helps to maintain balance in the body by getting rid of unnecessary components that would otherwise clog things up. Getting rid of these problematic cells is one of the top hacks for disease prevention, clear skin, fat loss, and longevity. Just think about that squeaky clean kitchen: it's bright, shiny and ready for anything you throw at it.
So, if these powerhouse processes are so crucial to our long term health goals, how can we activate them?
Here comes the insider secret…
The quickest way to hack your body into an optimized level of autophagy and Apoptosis is through fasting. As little as a 12hr fast induce autophagy in the body. Why is fasting necessary? Because when your body is expending enormous amounts of energy digesting your food all the time, it hardly has time for anything else. Let alone initiating amazing processes like autophagy and Apoptosis….
When we give our bodies a break from digesting food all day, from our mid-day snacks and "second-breakfasts," it actually has the chance to catch up, clean house, and provide us the support we need for optimal health and longevity.
If you want to give this a shot, autophagy can begin in the body in as little as 12-16 hours into a fast. Generally speaking, autophagy occurs once liver glycogen has depleted. Depending on the number of carbohydrates in your diet, this could take as long as 24-48 hours. It really depends on the person. If that seems a bit daunting, try your hand at intermittent fasting, which is a great way to dip your toes in the water. I recommend starting with a 16hr fast, giving yourself an 8hr eating window to play with. As you practice intermittent fasting more and more, you will reduce the amount of time it takes to deplete liver glycogen. Thus, you will reduce the amount of time it takes to induce autophagy.
Apoptosis is a bit less understood, and it's difficult to pinpoint when it happens. Apoptosis is more or less "pre-programmed" and is happening all the time in healthy human bodies. After a cell divides a certain number of times, Apoptosis goes to work. That cell self-destructs and is replaced by a shiny new cell! There is some evidence suggesting that during prolonged fasting (72+ hours), the body's ability to identify malignant or pre-cancerous cells is amplified and Apoptosis can carefully select and destroy the most "at risk" cells in the human body. This could be a powerful mechanism for disease prevention.
And finally, let's quickly dive into who fasting is for, and who may want to think twice before seriously incorporating fasting into their healthy lifestyle regimen.
For 90% of the people that come to my inbox, fasting is a wonderful, life-changing solution for disease prevention, fat loss, and health optimization. Overweight and obese individuals gain the most substantial benefits of fasting when they choose a 24hr+ fasting, pulling from the toolbox a host of helpful processes that burn thousands of calories of stored fat hanging out in their cells. Your digestive system has a chance to reset, take a breath and clean out all the muddy water that's been causing you discomfort. The list goes on… and on…
Because I'm not a doctor, I want to put a disclaimer here regarding my passionate belief in the benefits of fasting: Again, I am not a doctor. I do not pretend to be a doctor. I'm not giving you medical advice. Anything I tell you is based on my own personal research, experiments, and experiences. I'm not telling you fasting will cure all your ailments. Picking up the fasting tool kit is a decision you have to make on your own.
That being said, I want to quickly outline who will not benefit from fasting.
Like I said above, on average, 90% of my clients that come to me benefit from a fasting experience. Whether it's a 24hr black coffee fast, a 48hr water fast, or a sustainable intermittent fasting schedule, I have seen incredible results and health improvements from countless clients who try their hand at fasting.
However, there are a few groups I'd like to highlight that I'd recommend stay away from fasting.
- Consult your Doctor if you are on any type of diabetes medication. Fasting can be one of the most influential and transformative hacks for someone with diabetes, virtually curing them of the disease when utilized in the right way. That being said, this kind of fasting treatment must be done under the supervision of a medical doctor, especially if you are on any type of medication. The mechanism of action in diabetes meds is to increase insulin response in the pancreas, which is virtually the opposite of what a fast does for the body. If you are diabetic and are looking to try your hand at a fasting treatment, your doc will have to adjust your meds to make sure you don't go into shock. To be safe, make sure you do this under medical supervision.
- Stay away from fasting if you are breastfeeding or pregnant. Calorie consumption and maintenance is most important for women when they are pregnant or breastfeeding. There are a whole host of hormonal differences and changes. Just don't even try to mess with it. Let your body do its thing for as long as it needs to. You (and your new baby) will thank you.
- Stay away from fasting if you have had an eating disorder in the past. There's a belief that surfaced in the past that argues utilizing fasting for fat loss benefits causes the development of eating disorders and/or unhealthy eating habits in those susceptible to these kinds of things. Personally, I do not believe this to be the case. On the contrary, I think fasting is a great mental reset for anyone who spends too much time thinking about food. I will say, however, if you have struggled with unhealthy eating habits in the past and feel triggered by the concept of withholding or delaying food, rethink fasting before you dive in. Only you can make the decision about this one. Fasting is NOT a tool for starving yourself, and it is not an excuse to "not eat enough." One of the most critical keys to fasting effectively is making sure you're getting enough calories within your eating window, so your body doesn't kick into starvation mode (essentially ruining all the wonderful benefits you just worked so hard to achieve while fasting). If you feel like fasting will send you on a downward spiral, take some time to decide what's best for you.
- Extremely Active/ Stressed Individuals. Fasting has become very popular among Biohackers. The only problem is, Biohackers tend to be very Type-A, driven, and disciplined individuals. They're usually already eating a perfect diet and living with good body composition. Probably training multiple times per week, optimizing their sleep schedules, taking cold showers, meditating and kicking ass at their chosen profession. To be clear, fasting is a stressor. If you're already burning the candle at both ends in your day-to-day life, you probably don't need the additional stress of fasting. Eating a whole food diet with proper macros and optimizing other aspects of your health such as sleep quality and exercise will easily yield you the vast majority of the benefits you'd get from fasting. If you want to learn more about stressors and the dangers of "stacking stressors" check out my episode, "Stress Sucks!"
Finally, I just want to take a moment to reiterate how vital I believe fasting can be in getting you to the level of health you deserve… the level of health I believe everyone deserves! I have been researching nutrition and fitness for over 15 years. I am a Certified Nutritional Therapist, a Specialist in Sports Nutrition, and a Specialist in Fitness Nutrition. I have helped over 600 clients transform their health, and I can safely say that throughout my entire career, my body of work, and experience, I have yet to find a single therapeutic modality more potent than fasting. The results I have seen people achieve through this simple practice that has been available to us, for free, since the dawn of time is nothing short of amazing!