What is Intermittent Fasting and How is it Done?

(Last Updated On: December 13, 2018)

Intermittent fasting is one of the most discussed dietary concepts right now. Just like many other diet concepts, intermittent fasting (IF) is growing by leaps and bounds; however, unlike most of the other diets out there, IF is gaining ground even though it challenges many traditional assumptions and practices. I can attest that it has changed my overall concepts on what I think about nutrition.

I stumbled upon IF when I received an email from the great minds at Precision Nutrition. I realized that IF forces you to eat in direct opposition of my past assumptions, and that along with the results is why more and more people are experimenting with this new form of eating. I am a firm believer that this is not just some trend. It’s a massive shift that will change the way people eat, make their lives easier and more convenient, and reshape their bodies.


Intermittent Fasting Definition 

The most accurate definition is the simplest one: IF is alternating intervals of not eating (fasting period) with times where you are allowed to eat (feeding period). How long each window lasts depends on the method that you choose to use and there are several ways you can implement IF into your lifestyle. That is the beauty of it and why it works so well.

Each option has its benefits. The choice really depends on your personal preference and lifestyle. In general, each plan is about 16-36 hours with several stops in between with each strategy offering its own unique benefits.



Why Use Intermittent Fasting?

 Intermittent fasting provides two very important benefits that both relate to long term weight loss:

  1. Fasting puts your body into the most efficient fat burning environment possible by stimulating your fat burning hormones and suppressing your fat gaining hormones.
  2. Fasting is the ultimate lifestyle that people can maintain to stay leaner in a much easier fashion. It also allows you to push a reset button on your eating and it never leaves you feeling guilty if you overeat. If you decide to engage in IF, you can eat large calorie meals and not worry as much about the consequences. Since you fasted for a period of time you have limited the times that you can consume food, thus reducing your overall caloric intake.


8 Benefits of Intermittent Fasting


1 Intermittent fasting is the easiest way to restrict calories

Intermittent fasting is the easiest nutritional lifestyle that allows you to stay within your target calories without endless hunger pangs. It even gives you some elbowroom to make mistakes.


2 Intermittent fasting gives you more appetite control

Hunger isn’t driven by physical needs as much as cognitive factors. Oftentimes you’ll find yourself eating when you think you’re hungry, but it’s not when your body really needs food. In fact, your body has a tremendous capacity to store food and energy and work efficiently.  We negatively affect that process by stuffing ourselves with food when it’s not needed or wanted.  There is no benefit to frequent eating. You are actually training your body to be hungrier. Eating frequently does not increase the metabolism


3 Intermittent fasting makes you more productive

One study found that healthy young adults who ate as little as 300 calories over a two-day period experienced no decrease in brain tests and cognitive performance (including vigilance, choice reaction time, learning, memory and reasoning), activity, sleep and mood.


4 Intermittent fasting reduces your glucose/sugar levels

When trying to lose weight and burn fat, lowering your blood sugar is important to avoid pre-diabetes, diabetes, insulin resistance and most importantly becoming overweight. The norm in the fitness industry is that by eating 5 to 6 frequent meals a day you would regulate blood sugar levels. This has been proven to do the exact opposite. By fasting you could decrease your sugar input by anywhere from 15-30%. This improves your ability to burn fat and improve your insulin sensitivity.


5 Intermittent fasting increases fat oxidation

Fat oxidization refers to your body’s ability to use stored fat to produce energy, a process that normally happens during exercise. When using IF, you are increasing your body’s ability to use your stored fat as energy. This means that when you are burning calories more of those calories will come directly from fat.


6 Intermittent fasting is the fastest way to eliminate waste from the body and lower inflammation

Short term fasting actually helps you eliminate waste in your body and can speed up the healing process by lowering your inflammation levels. Metabolic inflammation is the inappropriate activation of your immune system, which can disrupt many of your body’s systems and can have severe effects on weight retention and weight gain. And this is important because nearly half of Americans have metabolic inflammation without even knowing it.


7 Intermittent fasting helps unleash the power of growth hormone

This is the biggest benefit that you will give yourself when adopting an IF lifestyle. You increase your ability to stimulate your fat burning hormones at an optimal level. Here, the biggest player is growth hormone.

Growth hormone is a protein-based hormone that is produced by the pituitary gland. It stimulates growth of cell reproduction and regeneration in humans and animals. GH is research-proven to be the best fat burning, anti-aging and muscle building hormone your body produces. Growth hormone incinerates your fat and denies fat cells from ever forming. Growth hormone helps you build muscle and helps make you look younger.


8 Intermittent fasting helps you never feel hungry again

The hormone Ghrelin is another very important piece of the fat loss puzzle. As we all have experienced, hunger is one of the hardest parts about eating correctly. Many people also experience irritability and mood swings if they don’t eat. Ghrelin also affects these feelings. Every time Ghrelin is secreted in your body it creates a hunger response. The more times you delay your hunger response you train your body to handle the hunger inducing effects of Ghrelin.

Increased production of Ghrelin also means you increase more growth hormone in your body as well. The more you are able to delay your hunger response and incorporate periods of short term fasting into your lifestyle, the more growth hormone and Ghrelin you’ll have pumping into your body.


        Fitness transformation Jen Mezzetti

The Various Ways to Implement Intermittent Fasting

There have been many Intermittent Fasting methods presented and studied by various people. I am going to briefly outline each method. I feel all of the IF methods have their benefits. I am a firm believer that there are always a few different ways to get the job done, and it all depends on the person and their lifestyle. Keep in mind that IF is not for everyone, but I do feel everyone should at least give it an honest effort.

Take a look at each method and try a couple of them to see which one works for you. Later on, I will talk about some of my own experiences. I will also refer you to Dr. John Berardi’s Intermittent Fasting book, as he beautifully outlines some of his own experiences, as well as some studies on the various methods of IF.


Alternate Day Fasting (ADF) By Dr. Michael R. Eades 

(36 hour fast / 12 hour feed)

With this plan you simply eat every other day. So on Monday, you’d eat within a 12-hour window, say, 8 AM to 8 PM. Then you’d fast overnight on Monday, and all day/overnight on Tuesday. You’d eat again from 8 AM to 8 PM on Wednesday. And so on. Alternate day fasters are encouraged to make good eating choices, but they’re allowed to eat what they want on the non-fasting days.




Some IF proponents believe we should behave like our evolutionary ancestors did. As humans evolved to get their food and exercise randomly, so should we. This brand of IF includes eating unprocessed “evolutionary friendly” food (think Paleo-diet type), randomly cycling daily caloric intake, and randomly skipping a breakfast or dinner meal once or twice a week. The rules are very flexible. (It is random, after all.)


Eat Stop Eat by Brad Pilon

 (24 hour fast, 1 or 2 times per week)

On this plan, you fast for a full 24 hours once or twice per week, eating sensibly (higher protein, minimizing processed foods, etc.) the rest of the week. It’s flexible: You can choose whichever 24 hours you want. Want to fast from breakfast to breakfast? That’s cool. Just eat breakfast on Monday, and don’t eat again until breakfast on Tuesday. Want to fast dinner-to-dinner? That’s cool too. Eat dinner on Wednesday, and don’t eat again until dinner on Thursday.


Leangains By Martin Berkhan

(16h fast / 8h feed)

This brand of fasting is based on an 8-hour feeding period followed by a 16-hour fast. However, it also layers a few other food rules on top. The diet should be high in protein, should cycle carbohydrates, should include fasted training, and should use nutrient timing (eating the bulk of your calories during the post-exercise period). On this plan, you fast from, say, 9 PM on Monday night until 1 PM on Tuesday afternoon. If you were going to exercise, you’d do so just before 1 PM on Tuesday, with 10 g BCAAs (branched chain amino acids) during training. After training, you eat 2-3 meals before 9 PM, with your biggest meal coming right after exercise. The fast begins again on Tuesday evening until Wednesday at 1 PM, and repeats every day.

Old school eating myths


Warrior Diet by Ori Hofmekler

(20 hour fast / 4 hour feed)

On this plan, you fast for 20 hours each day, working out during your fasted state. Then, eat your daily food intake within the 4-hour feeding window. After that 4-hour feeding period, fast again for 20 hours. Generally, most people place their 4-hour feeding window at the end of the day, as it’s more convenient for family dinners and after-work training sessions. However, the 20 hours of fasting and 4 hours of feeding can occur any time during the day.


My Intermittent Fasting Experience

I have totally loved experimenting with Intermittent Fasting and now practice it almost daily. I first became intrigued with it after I did a 5-day cleanse where I fasted for 5-days and took a colon cleanse supplement to start the New Year. As I continued to learn more about IF from Dr. John Berardi, Mark Sisson, and Neghar Fonooni, I quickly became a believer. After a while, I realized that almost every top guru in our industry was having some major success with his or her clients. So now I have been helping my clients understand and believe in the benefits of such a lifestyle.

I started by performing the Eat Stop Eat method developed by Brad Pilon. At first I thought this was the easiest way to go for me. I always did it on a busy day like Monday, and after the fasting window, I usually ate more food than I should have. This made it perfect to push the reset button and start the week off right. I felt my digestion improve and my hunger became under control. I was hooked! I would go the full 25 hours without food, and only consume cod liver oil, branched chain amino acids, Juice Plus and plenty of water.

I now have begun to practice the Lean Gains method by Martin Berkhan. I have found that this method makes the most sense for me. I am someone that does not need to eat before I workout. Quite honestly, I feel that if someone is healthy and already active, they should have no problems working out on an empty stomach, or with just a scoop of BCAA powder. But I do understand there are certain cases where some people just need a little fuel in the tank.

With the Lean Gains method, I would typically have my last meal between 7pm and 8:30pm. I would wake up and take my BCAA powder and Juice Plus with plenty of water, and another scoop of BCAA powder after I workout. My first meal of the day would be a super shake between 12pm and 1pm. I would then eat another high protein and fat meal a couple of hours later, and then dinner when I got home. This has made my everyday eating so simple. I am satisfied, have great energy, my digestion is great, and I don’t miss eating breakfast at all. It is super convenient, and takes way less food prep time. I basically just have to prepare a super shake, a small snack and dinner.

Below is an example meal plan of the Lean Gains IF method



Fast throughout the morning. Drink plenty of water and/or green tea.


Consume 1 scoop of Modern Branched Chain Amino Acid (BCAA) supplement before and after workout.

Meal 1

  • 2-3 scoops whey protein powder
  • 1-2 tablespoons Carlson’s Cod Liver Oil
  • 1 heaping tablespoon of Vitamineral Greens
  • You can add some fruit if you would like, but I just skip it for convenience

Meal 2

  • 6-8oz. meat OR 1 cup Greek yogurt
  • 1-2 cups vegetables
  • 1-3 tablespoons of almond or peanut butter

Meal 3

  • 6-12 oz. of meat
  • 1-2 tablespoons of some kind of fat such as extra-virgin coconut oil or extra virgin olive oil
  • Small serving of some type of functional carbohydrate such as quinoa, potato, or sprouted grains
  • 1-2 cups of vegetables


  1. Intermittent fasting is the most efficient and effective way to put your body into a natural fat burning, muscle building, metabolism-increasing environment.
  2. Intermittent Fasting gives you the ultimate appetite control by controlling the hunger effects of Ghrelin.
  3. Intermittent Fasting offers you the ultimate caloric “wiggle room” in your daily nutrition.


Fat Loss Forever Nutrition Manual By. Roman Fitness Systems

Experiments with Intermittent Fasting by Dr. John Berardi with Dr. Krista Scott-Dixon and Nate Green