Intermittent fasting is all the craze right now, among fitness and health enthusiasts young and old. Yet, it’s nothing new. In fact, it’s been used—though likely unintentionally—for longer than you and I have been alive.
Our hunter/gatherer ancestors fasted simply because food was scarce. Since they had to find their food before they could eat, if the food was too fast, well, you could be waiting a while. Makes you grateful for the grocery store. Of course, that convenience can be a drawback with the overabundance of many unhealthy foods.
Intermittent fasting has been gaining popularity today as an effective way to control food intake. As you are well aware, we have a lot of food available and many are eating it. Ironic, right?
Before I get ahead of myself, let me explain what fasting is and the benefits of the intermittent fasting strategy.
Fasting is simple: it’s the voluntary abstinence from eating food and/or drinking calorie-containing liquids for a specified period. I highlight the word voluntary because there’s another extreme form of involuntary abstinence from food, and its called starvation.
As I mentioned earlier, fasting’s not new, nor was it originally implemented for weight loss. In fact, Judaism, Islam, Christianity and other religions have been using fasting for centuries. For Islam, it’s most common during Ramadan.
For Christians, fasting dates back to the Bible’s Old Testament. Many Christians observed a 40-day fast during Lent (before Easter) and Advent (before Christmas). Roman Catholics have modified their fasting ritual to include only Ash Wednesday and Good Friday.
In Hinduism, fasting is traditionally observed on certain days of the week or month, such as Purnima and Ekadasi.
While people have fasted for hundreds of years, intermittent fasting is now being used to improve health and body composition. You see, strategically including intermittent fasting into your lifestyle has a potential multitude of health benefits. Even a single fasting interval (e.g., overnight) appears to reduce insulin and glucose as well as other markers for certain diseases.1 This explains why patients are required to fast for 8 – 12 hours before blood draws: to achieve steady-state fasting levels for many metabolic substrates.
Several studies suggest intermittent fasting may have some benefits that directly affect metabolism and potentially longevity.2 When you combine calorie restriction with intermittent fasting, research indicates it may prolong the health-span of the nervous system by affecting fundamental metabolic and cellular signaling pathways that regulate life-span.3
Many of us eat out of habit (the clock says it’s time to eat), out of convenience (it’s there), or because our hunger hormones tell us to do so (I’m hungry). In the case of the latter, the body gets used to cyclical feeding patterns. As a result, many of us experience hormonal hunger, which isn’t true, deep hunger. Rather, it’s just because the body is expecting food. I personally think intermittent fasting gives us the opportunity to realize what REAL hunger feels like.
With intermittent fasting, when we experience hormonal hunger—which is sometimes purely psychological—we are forced to sit through it and let it pass. This teaches us that hunger isn’t an emergency and will pass, even if we must endure three hours (gasp) without food.
What’s more interesting is that hunger hormones are trainable. In other words, you may have noticed you get hungry at the same times every day—regardless of what you eat for lunch. Intermittent fasting can help re-train your hunger hormones, putting you in the driver’s seat of your appetite.
Furthermore, fasting reminds us that eating is a privilege. Not everyone can eat every two to three hours or even daily. Moreover, eating’s a responsibility, in the sense that what we put into our bodies is fuel and we’re reminded during intermittent fasting.
Essentially, our bodies are our vehicles. Do you want to opt for low-grade/low-octane fuel because it’s cheap? Or, do you want to high-octane rocket fuel that will fuel you and your goals properly?
In addition, intermittent fasting reminds us of ever-present food marketing. It’s everywhere! No wonder we think we need to eat all of the time! Our sensory perceptions are heightened each time we see an ad for food or drive by a fast food joint.
Here is a list of all of 10 potential health benefits of intermittent fasting:
There are several ways you can incorporate intermittent fasting. One of the most popular is Time-Restricted Feeding (TRF). As the name implies, TRF involves extending the amount of time you fast each day, while restricting your window of eating time. Most TRF programs involve a feeding window of 4 – 8 hours with a fasting period of 16 – 20 hours.
The most-studied form is Alternate Day Fasting (ADF). ADF consists of a fast day (which involves either a complete fast or up to about 500 calories) alternated with a feed day (where you eat according to your hunger). The rationale behind ADF is that many people have a difficult time with daily caloric restriction, and with ADF, you only restrict calories every other day. ADF has been shown to be a safe and effective approach for weight loss and is at least as effective as daily caloric restriction. Even more, ADF has been shown to improve markers of heart health and insulin sensitivity.
The most popular ADF diet is The Every Other Day Diet based on research by Dr. Krista Varady. In addition, there are other popular intermittent fasting diets that are based on ADF, such as Eat Stop Eat and the 5:2 Diet. Instead of alternating fast and feast days, these diets simply involve scheduling two fast days each week. They’re a bit more practical and easier to follow than the standard ADF protocol.
Finally, one additional form of intermittent fasting is the Fast Mimicking Diet (FMD). FMD is based on research conducted by Dr. Valter Longo and colleagues and involves fasting for a single 5-day period during a monthly cycle. The rest of the time, you eat normally.
During the five-day FMD period, you don’t actually have to fast. You simply follow a low-calorie diet (about 33 – 50% of your normal intake) that’s also low in protein (about 9 – 10% of your normal protein intake) with the rest of your calories split between carbs and fats. The benefits of this intermittent fasting strategy are:
I’ve personally used a modified version of the 5:2 Diet with Time-Restricted Feeding to remarkable success. On non-weight training days (2 days a week), I fast at least 16 hours, with the goal of hitting 20 hours with no food (just black coffee and water). I try to get in 30-40 minutes of cardio on those off days – and reduce my protein (protein cycling) and focus on healthy fats and fibrous carbs (veggies). I can lose ½ – 1 lb. of stored fat each day! The other 5 training days I eat clean – but add in 2x my lean body weight in grams of protein and only consume carbs an hour before, during and after my weight training session. Healthy fats are the staple of calories (along with the protein requirements to build muscle) of my diet.
Once a week (on a heavy training day), I’ll add an extra 500-1,000 calories (cheat meal) – of my favorite foods (pizza, chocolate cake) – generally right after heavy-leg or back days!
So, there you have it! Fasting is not only good for you mentally, but also physically. Retrain your system with days of fasting and then enjoy what you like and you’ll see better healthy results all around. Now, for my pizza… I chose the right day to write this article!