What Is Intermittent Fasting?

Chapter 1

Intermittent fasting: An introduction

Some people say intermittent fasting is “like magic.” But sifting through all the different intermittent fasting schedules and the mountains of research on fasting is a major undertaking. In this FREE ebook, we’ve done the heavy lifting—so you can decide whether intermittent fasting is right for you.

Maybe you’ve had this experience. A friend becomes evangelical about intermittent fasting (IF), telling you: “It’s sooooo easy. I just don’t eat until 3pm.”

Your friend has never felt this good. They’re buzzing with energy and focus. And they look incredible.

This fasting thing? It’s working for them. You think, ‘Hm, maybe I should give this a try?’

And almost as soon as you’ve had that thought, another friend comes along with their IF experience.

“Ugh, this stupid IF diet,” the other friend says. “I’ve. Never. Been. This. Hungry. In. My. Life.”

That friend seems drained, stressed, angry—like the main character in a Snickers commercial.

So maybe… IF isn’t for you, after all?

Such conversations can lead any thinking person to wonder:

• Does IF even work? And what, technically, is IF anyway?
• Who should try IF? Who shouldn’t?
• What are the pros and cons?
• Of the many different IF schedules—16:8, 20:4, 5:2, among others—which one works the best?

In this FREE ebook, we’ve answered the top intermittent fasting questions.

You’ll find everything you need to decide whether IF is a good fit for yourself (or a client) and, if so, how to use IF for best results. Read it in order. Or start with what attracts your interest first. It’s all good.

Our team has deep, personal intermittent fasting knowledge.

If you’ve never heard of Precision Nutrition, then you might be wondering:

‘Who the heck are these folks, and why should I trust them?’

Briefly, Precision Nutrition:

• Is the home of the world’s top nutrition coaches.
• Offers the #1 most recommended nutrition coaching certification program in the world, according to third party data.
• Has helped over 150,000 clients transform their bodies and lives.

But there’s more.

Most of our team members treat themselves like lab rats.

(You might think of experimentation as an essential ingredient in the Precision Nutrition culture.)

They’re constantly trying a variety of nutritional strategies. And intermittent fasting is no exception.

Several years ago, John Berardi, PhD, our company co-founder, and Krista Scott-Dixon, PhD, our director of curriculum, experimented with intermittent fasting for several months.

Along the way, they kept meticulous notes on everything from scale weight, body fat percentage, and blood/hormonal markers, to lifestyle considerations like energy levels, cognition, and pain-in-the-ass factors.

Throughout this ebook, we’ll reveal what they discovered—and how it can help you nail the art of intermittent fasting.

(And, don’t worry: In addition to their personal experiences, you’ll find plenty of science and research.)

We’re not here to talk you into or out of any diet—including intermittent fasting.

But if you’re going to try IF, we want to help you do it right.

Dr. Scott-Dixon and Dr. Berardi both learned many IF lessons the hard way.

(And yes, they’ve revealed those humbling experiences in this ebook.)

Based on their takeaways, they developed a way to find your intermittent fasting sweet spot: just enough IF to get awesome results, but not so much IF that your dog’s kibble looks appetizing.

By coupling their fasting experiments with the latest science, we’ve created a comprehensive resource that can help you and your clients:

• Decide whether IF is right for YOU.
• Maximize the benefits of IF and minimize the risks.
• Figure out which protocol to try.
• Personalize IF to your goals, needs, and life in general.

There are two ways to use this ebook.

If you’re a trainer, coach, or other health and fitness professional:

• Get curious about the science behind IF. You’ll find that in chapter 3. The more you understand, the better you can communicate with clients who have questions about it.
• Consider having a resource for clients who are interested in trying IF. And please feel welcome to point clients to any part of this ebook if you think they’ll find it helpful.
• Monitor and support clients closely. If your clients are trying IF, be available to talk through any challenges or prevent problems before they happen.
• Recognize which clients, if any, IF might be appropriate for. There’s no “one-size-fits-all” protocol. Understand who IF might—and might not—work for, and be responsible to the people you serve.

If you’re interested in trying IF yourself or simply want to learn more about it:

• Go slowly. There’s no rush. We’ll show you how to get started and how to personalize intermittent fasting for your needs.
• Know yourself. Pay attention to things like your energy, sleep, recovery, mood and mental state, behaviors, and relationships. If you notice problems, deal with them immediately. “Faster/harder/more” is almost never the answer.
• Consider coaching. Having ongoing supervision, support, accountability and guidance is usually a good thing.
• Check out our self-experimentation guidelines. In chapter 8, we’ve given you a step-by-step process that you can use to navigate your own IF exploration.

About the experts

Helen Kollias, PhD, is Precision Nutrition’s science advisor. An exercise physiologist, Dr. Kollias earned her doctorate in Molecular Biology from York University in Toronto, specializing in the area of muscle development and regeneration.

In addition to teaching exercise physiology, molecular biology, and biochemistry at the university and college level, Dr. Kollias has held research positions at some of the most prestigious institutions in the world, including Johns Hopkins and Toronto’s Hospital for Sick Children. Her work has been published in 10 scientific journals.

John Berardi, PhD, is the co-founder of Precision Nutrition.

He holds a doctorate in exercise physiology and nutritional biochemistry from the University of Western Ontario and an MS from Eastern Michigan University.

The author of the best-selling book Change Maker, Dr. Berardi’s been recognized as one of the top exercise nutrition experts in the world. His work has been published in numerous textbooks, peer-reviewed academic journals, and countless popular exercise and nutrition books and magazines.

Krista Scott-Dixon, PhD, is Precision Nutrition’s director of curriculum. She leads the development of PN’s educational programs and courses, including the Precision Nutrition Level 1 Certification and Level 2 Certification Master Class.

Dr. Scott-Dixon holds a doctorate in Women’s Studies from York University. With more than 20 years of experience in research, adult education, curriculum design, and coaching and counseling, Dr. Scott-Dixon has written several books, dozens of popular articles, and many academic publications.