The Skinny on Intermittent Fasting: One size fits all?
By Marika Geis, BSc, ND
Even if you’re remotely interested in clean living and whole foods, you’ve probably come across the concept of intermittent fasting. It’s all the rage these days and with good reason. It balances hormones, improves sleep, boosts mood and mental clarity, promotes weight loss and increases energy. What’s not to love? But it’s also not for everyone, and the method of intermittent fasting might look differently from one person to the next. One need only to consider the various spiritual traditions that use it as a practice to get a sense of all the different ways it can be implemented. The B’hai faith requires a 19-20 day fast from sunrise to sundown, similar to the Muslim holiday of Ramadan which requires a 30 day fast. In Judaism, we have many obligatory fasting days, the most notable being Yom Kippur. As Roman Catholics we are familiar with the season of Lent which evolved from a one week fast prior to Easter to a month with no meat on Fridays.
Beyond some of the assumptions we can make about what it was like to live thousands of years ago, clearly, we have a long historical record of fasting. Yet we have been conditioned to believe that fasting is something to avoid at all costs. It presumably poses a significant challenge to maintaining health in that the ‘starving’ state poses an unnecessary stress on our bodies. We’ve thus trained our bodies to eat every 2-3 hours out of perceived ‘necessity’. I ask you, how well would that strategy have served us as we evolved as bi-pedal primates over 2 million years? We certainly didn’t have Safeway, corner stores, refrigeration and semi-truck-trailers bringing food from around the globe. Yet we survived and thrived. How? We needed a metabolic strategy to keep us going when food was scarce and one when food was plentiful. Intermittent fasting allowed for the metabolic flexibility required to survive the ever-changing landscape that was our home. Simply put, we are built for intermittent fasting and by training our bodies as we have done in modern times, we lose that metabolic flexibility and herein lies one of the root causes of the so called ‘diseases of civilization’, but I digress…..
Intermittent fasting loosely defined is any period of time without eating lasting more than 14 hours and no more than 24 hours with a ‘feeding window’- the amount of time within 24 hours not occupied by fasting (eg. 16 hours of fasting with 8 hours of ‘feeding’). The easiest way to do this is to simply skip breakfast (as hours spent sleeping are included in the fast) and gradually work up to the desired interval. HOLD THE PHONE!!! WHAT?! You say? Breakfast is the most important meal of the day! It well might be if you’ve trained your body to rely solely on carbohydrates for fuel (like most of us). Your body does not have the metabolic framework to access the energy rich fats in your body and diet and relies on regular doses of carbohydrates to keep going.
Skipping breakfast might very well feel like dying for some, however, once a few of the obvious imbalances have been addressed (a little farther down), intermittent fasting can curb cravings, restore energy, promote deeper sleep, correct inflammation and destroy bacteria and viruses otherwise refractory to treatment. Add to this list the following:
- Improves longevity
- Improves insulin sensitivity – Dr. Jason Fung, nephrologist and co-founder of the ‘IDM Program’ in Toronto, routinely gets insulin dependent type 2 diabetics OFF their insulin injections.
- Lowers cholesterol, triglycerides and glycosylated hemoglobin (HbA1c): a 3-month measure of blood sugar regulation.
- Fighting/preventing cancer. There is some evidence that fasting before chemotherapy can help reduce side effects.
- Increasing growth hormone secretion (which builds muscle/bone and burns fat).
- Normalizes expression of the ‘hunger’ hormone ghrelin, thereby reducing appetite.
- Promotes brain and nervous system health by increasing neuronal plasticity (adaptation) and promoting neurogenesis (creation of new nerves), thus boosting mood, memory, and mental clarity.
- Increases dopamine production. This boosts mood and increases anticipation and response to rewards (meaning we get more enjoyment from less food).
So, how does intermittent fasting work, anyway? ‘Autophagy’ is the process by which weak cells break down dysfunctional components. Remnants are reallocated to neighboring cells and recycled making cells healthier and more efficient. This process of autophagy is what allows for the destruction of bacteria and viruses that would otherwise have either gone undetected or were refractory to pharmacological treatments. Autophagy plays a critical role in managing both the beneficial and detrimental effects of inflammation as mediated by the immune system. In other words, it protects us against infectious disease, autoimmune and other inflammatory conditions.
There are many options to intermittent fasting. There are even benefits to doing it occasionally. Regardless of what you choose, generally speaking, it can be done once to three times weekly safely (barring confounding health concerns, discussed below). Clear fluids are allowed, including bone broth (without the fat- for FASTING ONLY. Otherwise, drink it all up). Intermittent fasting daily is no longer an intermittent fast; your body will adapt to the caloric intake of ‘the season’ and the benefits will be dulled. More isn’t necessarily better either. Play it by ear and see how you feel.
Who SHOULD NOT intermittent fast?
- Anyone with a history of disordered eating: anorexia nervosa, bulimia, orthorexia. Any kind of restriction can trigger old patterns, especially if they are in recovery.
- Absence of menses. It’s very important to realize that the mind needs to register ‘safety’ in order to carry out its housekeeping functions. Having a period is no different. So, if you’ve experienced extreme, rapid weight loss, excessive calorie restriction or if you have a known hypothalamic disorder (part of the brain that orchestrates hormone function), then intermittent fasting should wait.
- If you have to ‘push’ yourself to do it. Feeling hungry is a normal part of fasting, however if you start manifesting symptoms of hypoglycemia (low blood sugar), then this problem needs to be corrected prior to starting any type of fasting program, intermittent or otherwise.
- Adrenal dysfunction. Adrenal glands (the guys that rule our stress response) require a tremendous amount of nourishment. They need to be stable and well functioning, in other words – register ‘safety’ – in order NOT to be a factor when fasting. Fasting can worsen adrenal issues if the body doesn’t first have capacity for this physical stress. Likewise, if you’re experiencing unusual amounts of stress, intermittent fasting should probably wait.
- Thyroid dysfunction – as this is tied to adrenal function. They work in tandem to manage energy and metabolism in the body.
- Sleep changes – this likely indicates a hormonal imbalance or may point to the need for a ‘carb up’ if you’re following a high fat, low carbohydrate lifestyle.
- Gut imbalances (egs: leaky gut, bacterial overgrowth, allergies) – simply MUST be corrected first as too many health issues that destabilize the body stem from this crucial system. Remember that in order for intermittent fasting to be successful, the body must first have all it’s needs met. In other words: safety.
You may have the impression, after reading this list, that no one has the capacity to fast intermittently. I would agree that MANY people struggle with stress, gut, and hormonal issues such that health appears to be the exception and not the rule. However, when we align our body with how it wants to live, not how we think it should live, many of these problems can be repaired given the right intervention. For the lay person, fasting might feel extreme, but I’m wondering if there might be a little room for perspective. Intermittent fasting requires that we remove 1 (sometimes 2) meals a day 2-3 times a week. Out of 21 meals (and for some, more), this style of fasting requires you to limit a grand total of 14% less food in a week (this is if you’re doing it three times weekly, at one meal/fast). Not a big deal. If you’re the person that does intermittent fasting 1-2 times per month, then that number is even less. Intermittent fasting allows you to simplify your schedule, correct insulin resistance, promotes weight loss, and boosts cognitive function. So, if you’ve got the green light, what are we missing, really? And what do we gain? I’ll let you decide.
For the full article you can download it here: The Skinny on Intermittent Fasting.