Intermittent Fasting
Intermittent fasting (IF) has become a popular dietary protocol in recent years, gaining incredible popularity for its role in inducing positive physiological and biochemical effects in the body. The diet typically involves a period of time in which there is an absence of caloric intake, be it food or drink.
The benefit of the diet regime arises from what happens in the “fasted” state. The “intermittent” part is simply one possible way (of many) to include fasting into a dietary regime.
Fasting may be a convenient dietary regime for travellers whose busy schedules may fit well into an intermittent fasting window. Rather than sitting at home in front of the fridge or pantry, being on the go may help pass the hours during the fasting window.
Benefits of Intermittent Fasting
Boosts Growth Hormone. Fasting has been shown to significantly boost human growth hormone (HGH), the benefits of which are fat metabolism and an increase in lean muscle mass.
Improves insulin sensitivity. We want to be insulin sensitive. This means that our body reacts quickly to higher blood sugar and is able to move that sugar out of the bloodstream. If we have “low” insulin sensitivity, we do not do a good job at removing high blood sugar levels, which can (if left uncorrected) ultimately lead to Type II diabetes.
Helps clean our body at the cellular level. We all have a built in way of cleaning out old cells and proteins that gum up our body; it’s called autophagy. One might compare it to running a deep scan on our computer, ridding the computer system of old or corrupt files and leaving only the useful and functioning ones.
Boosts our brains. Intermittent fasting has been shown to protect our brains and boost brain function (especially memory), as well as reducing neurodegenerative disorders.
It’s heart healthy. Evidence shows that fasting may improve blood pressure and improve blood chemistry, with respect to “bad” cholesterol (LDL).
Reduces inflammation. Fasting has been shown to reduce overall inflammation in the body. See our feature on inflammation to understand how it has become the number one global health concern with respect to chronic disease.
Our modern American dietary regimes, with food at our fingertips, means that we often eat several meals and snack in-between, never coming close to a fasted state, which was so much a part of our evolutionary biology.
Fasting comes in many forms but always includes a period of food restriction (non-caloric liquids, like water are still consumed).
There are several ways to achieve the benefits of a fasted state. One of the most popular is “intermittent fasting”, which itself has many variations, the most popular of which is the 16:8 regime. In this schedule, the individual can only consume food during an 8 hour window, leaving 16 hours a day with no caloric intake. However, we can take credit for the time we’re sleeping, during which we aren’t eating, of course. As an example, if we stop eating at 8pm, we would skip breakfast, and begin eating again at 12pm (noon). When you think about it this way, it’s not too difficult.
There is some evidence that shifting the 8 hour eating window earlier so that we are not eating close to our bedtime is even more beneficial, a technique that considers how our metabolism follows our circadian rhythm.
Our modern American dietary regimes, with food at our fingertips, means that we often eat several meals and snack in-between, never coming close to a fasted state, which was so much a part of our evolutionary biology.
What Happens When You Fast?
A 2019 New England Journal of Medicine Review has become highly cited for its in-depth review of what happens inside our bodies when we fast.
About 10-14 hours into a fast, we have typically used all available liver glycogen stores. To get the energy we need, we start to release free fatty acids (FFA) into the bloodstream from our adipose tissue. The liver then converts the FFAs into keytones, which can be used as fuel in the body. Not only are we now burning fat as fuel, we begin a complex multi-organ response that results in substantial repair, reduced inflammation, and stress inoculation. It is almost if being energy depleted causes our bodies to remember how to function at a higher level, with improved mitochondrial function and stress defences.
The authors of the study note that it’s not only the fasting period that is important. They also studying the switching back and forth between fasting periods and feeding periods, and noted that this “metabolic switching” can remodel our tissues.
de Cabo, R. and Mattson, M. N Engl J Med 2019; 381:2541-2551
DOI: 10.1056/NEJMra1905136
Common Types of Fasting
Time-restricted eating. Fast for 16 hours; eat for 8 hours. Repeat. Known as 16/8. Can also be 14/10.
Eat/Stop/Eat. An example is not eating for 24 hours once a week. (Often dinner to dinner).
Caloric Reduction. This involves reducing total caloric intake. Often not done every day.
Whole Day Fasting. One meal a day, which means you are fasting for almost 24 hours a day.
Risk Associated With Fasting
Always seek the advice of a medical professional. Fasting may not be appropriate for those on certain medications, who are pregnant or breastfeeding, or have blood sugar issues. Always consider the combined effects of sleep deprivation, fasting, and unintentional dehydration, while traveling. Fasting can also reduce cognitive sharpness during the fasting period, so those who have to give presentations, have important meetings, or who act as an aircrew member or first responders, should opt for fasting practices that do not impact work periods. Always speak to your doctor prior to starting a fasting regime.
Why Fasting for Travellers?
Traveling brings with it unique schedules and environments. Sometimes, we find that our normal dietary routines are disrupted. Rather than snack on food that may not be healthy, travellers may choose to incorporate some methods of fasting during travel or during their vacation stay. For example, some travellers have employed the 16/8 method in locales where the breakfast foods are normally simple pastries but lunches and dinners are more delectable and extravagant. Fasting from 8pm to noon the next day (and missing the pastry) may not be a terrible inconvenience if one can look forward to fantastic meals in the midday and evening hours.
This article does not constitute medical advice. Always seek the opinion of a medical professional before starting a nutrition or fitness program.