Intermittent Fasting: A Beginner's Guide

Editor’s note: This is a guest post by John Berardi, PhD.

When we were kids, Mom was always looking out for our health. Chew your food. Eat your vegetables. And always eat breakfast because it’s the most important meal of the day.

As busy grown-ups, a good breakfast often falls victim to the time crunch. Who has time to cook and eat a breakfast of champions? It’s so much faster and more convenient to just grab a coffee and a bran muffin.

Of course, deep down we know it’s not right. Not only would Mom disapprove, that pudgy physique in the mirror deserves better, too.

So what’s a guy to do? Get up earlier and make it happen, right? Perhaps not.

Lately, some really fit guys–men with muscles, visible veins, and abs so sharp you can grate carrots on them–are doing something a whole lot different. They’re not eating breakfast. Healthy or otherwise. In fact, they’re not eating at all for extended stretches. And they’re getting leaner, more muscular, even healthier.

This practice is called Intermittent Fasting–IF for short–and it’s challenging everything nutritionists, dieticians, and your Mom ever told you about healthy eating.

Going Against the Grain

Typical dietician dogma involves eating small meals spread two to four hours apart, starting with a nutritious breakfast. This, we’re told, stimulates the metabolism, so we burn more calories throughout the day. It’s also supposed to make us less likely to binge on cookies and ice cream at night.

It’s sound advice that’s been field-tested by thousands of fit, healthy, hard-bodied people.

Proponents of IF, on the other hand, eschew the idea of small, frequent meals. They claim to have achieved quicker fat loss and better health by deliberately skipping breakfast. Some even go entire days without eating.

The experts are skeptical. They call IF extreme, impractical, even harebrained–and yet no one can dispute their results. Or that the number of IF converts is growing.

I was also a skeptic. I built my reputation on recommending small, healthy, frequent meals, starting with breakfast. And that strategy has definitely worked well for most of my clients.

But the track record of certain Intermittent Fasting protocols, both in scientific publications and in real-world practice, seems pretty impressive too. That’s why I decided to put some of these protocols to the test. I wanted to answer the following questions: “Is IF just another fad diet? Or is it something health and body conscious people should consider?”

My Fasting Experiments

To this end, I spent the last 9 months testing the most popular Intermittent Fasting protocols on myself. In the end, I tried 8 different fasting protocols.

At times I was consuming nothing but calorie-free beverages for a full 24-36 hours. (Mercifully that was only once per week.) Other methods had me fasting for much shorter periods, yet more frequently.

While each method was basically a spin on not eating a thing, the varying effects were fascinating. Some methods made me feel energized, strong, and focused. Others simply left me lethargic, weak, and very, very hungry.

Of the 8 different protocols I tried, there are three main variations:

The trial fast: This is where I recommend you start if you’re interested in this approach. Just try going 24 hours without food. I did my first trial fast on a Sunday. I set it up by having a small meal on Saturday night at 10pm, and then didn’t eat again until another small meal on Sunday night at 10pm. (I did drink green tea and water throughout the day.)

The periodic fast: If you survived the trial fast without breaking down and cleaning out the refrigerator, then you can try this. Simply do the trial fast above once in a while. It could be once per month. It could be once per week. (More frequently than once a week, however, is a mistake. I tried to do it twice a week and it was a disaster. More isn’t better.)

The daily fast: This is a more advanced way of doing things. Here we cut the fast from 24 hours to 16-20 hours (say 8pm to noon to 4pm the following day) but we do it every day. Ideally, most days there’s a workout at the end of the fast, followed by some pretty large meals during the 4-8 hour feeding window. (As complicated as this system sounds, I found myself actually gaining muscle and losing fat at an alarming rate.)

So what’s the conclusion? What did I learn?

Well, for body transformation, Intermittent Fasting works. Over the course of my experiments, I dropped twenty pounds of weight, from 190 pounds to 170 pounds, and I was pretty lean to start with. I also reduced my body fat from 10% to 4% (measured via a well-validated ultrasound protocol) while maintaining most of my lean mass. And I kept it off. In addition, I saw some interesting improvements in my health profile.

You can check out my before and after pics below for some visual evidence:

Man showing muscles in different positions.

Man showing muscles in different poses.

Beyond vanity, the reported health effects of an intelligently designed Intermittent Fasting program read like a laundry list of live longer, live better benefits including: reduced blood lipids, blood pressure, markers of inflammation, oxidative stress, and cancer. Increased cell turnover and repair, fat burning, growth hormone release, and metabolic rate. And improved appetite control, blood sugar control, cardiovascular function, and neuronal plasticity.

Wow is right! At this point, if your wheels are turning, that’s a good thing. But be careful. This article isn’t designed to persuade you to try Intermittent Fasting right away. Rather, it’s designed to simply get you thinking about your own eating plan. And, if it needs improvement, how you can think about starting.

Listen to my interview with John about IF:

Fasting Best Practices

If you’re a busy guy, work 50 plus hours a week, and spend most of your free time shuttling kids around and working the honey-do list, working out daily and eating 6 meals a day may be challenging. So skipping a few meals and looking like the Men’s Health cover model may sound pretty appealing.

But not so fast. You can’t just skip meals willy-nilly and get awesome results.

Remember, some of these fasts follow very specific protocols. Just eating haphazardly and then not eating is what gets many people overweight in the first place. But if you’re keen on giving IF a try, here are 9 things that you must first consider.

1. Food choices matter. Just because you’re not eating often doesn’t mean the basic rules of good nutrition don’t apply. Fasting for 20 hours and then spending 4 hours eating pizza, Twinkies, and half your kid’s Halloween loot won’t get you lean. You need to focus on good sources of protein, healthy fats, high quality carbohydrates, and lots of fruits and veggies. (Your mom was right about that one.)

2. Be patient. If you’re a big fan of breakfast, fasting is going to be a major test of willpower–especially for the first few weeks. In my case, the early stages left me suffering from massive stomach rumblings, hunger cravings, and big-time morning moodiness. I did my best to stave off the breakfast cravings with a few cups of green tea or coffee, but I still felt really bad. Luckily, I told my friends and family what was going on, and they’re a pretty understanding bunch. But here’s the good part. It gets better–much better–after 14 days or so. Stick it out. You’re not dying –you’re just hungry.

3. Exercise helps. The best fasting protocols had me hitting the gym as hard as ever, empty stomach be damned. There’s a reason for that –exercise drives the fat loss bus.

4. Timing is everything, but not the only thing. I experienced the best results when I fasted for around 16-hours per day, followed by an 8 hour eating window. I usually ended my 16-hour fasts with a workout. Then I ate my largest meal of the day. However, other less stringent protocols also delivered results. Experimentation is the key.

5. Progress slowly. It’s important to start with the trial fast and allow yourself to get “good at it” before graduating to more frequent or complicated fasting protocols. Many find going just a few hours without eating unbearable. It takes practice and willpower, so be patient. Dominate the easy steps before moving further up the fasting ladder.

6. Don’t overdo it. In my case, after achieving great results with a weekly fast, I tried doubling the frequency to twice a week to see if I’d get twice the results. It didn’t happen. More isn’t necessarily better.

7. Eat meat. I ate upwards of three pounds of meat a day to get my calorie and protein requirements. Now, I’ve always been an omnivore, but during extended fasts, where meals are so infrequent, eating meat is even more important. Of course, you can still do this if you’re following a vegetarian diet. It’s just more difficult to meet your calorie needs for the day.

8. It’s still a lifestyle. There are no diets, only lifestyles. And any diet that you couldn’t theoretically follow for the rest of your life is doomed to failure. During my first few fasts I was convinced that there was no way I could eat like this for life. But after a few weeks, I was loving it, and it was a breeze.

9. Some shouldn’t do it. I think anyone and everyone should attempt the trial fast. Trust me, you learn a lot about yourself when you go without food for a full day. However, for the more regular or more extreme forms of fasting, I’ve found they’re more successful when:

You have a history of monitoring calorie/food intake (i.e. you’ve “dieted” before).
You’re an experienced exerciser.
You’re single or you don’t have children.
Your partner (if you have one) is extremely supportive.
Your job allows you to have periods of low performance while you adapt to a new plan.

Granted, these are just observations. There are folks who have kids, busy careers, and tons of responsibility who love IF. And again, the real rough period usually ends after two weeks or so. However, if it’s not for you, it’s not for you. Again, there are other ways to eat and exercise to develop a lean, strong, healthy body.

Remember the Basics

One more thing. It’s important to remember that there’s no magic pill (or magic eating plan), and when all’s said and done, mastering the basics is still your best approach. What are the basics?

Eating good quality food. Fresh, unprocessed, nutrient-dense food is a must, regardless of eating style. So make food awareness a priority and make the best choices you can afford.
Eating slowly. Rushing through meals impairs digestion and confuses satiety centers in the brain. So slow down. It helps control intake and improve your enjoyment of eating.
Eating reasonable portions. When calories are controlled, progress is made. Overeating is still possible with IF, just as it is with every other eating style. So pay attention to food amount.
Eating when you’re hungry, and not eating when you’re not. Learning to tune into your appetite and listen to your true hunger is important. Using mindfulness during meals is a best practice for healthy eating.
Regular exercise. Of course, exercise and healthy eating are two sides of the same coin. They both help promote health and a lean body but in different ways. So use both.

Interestingly, these things are enough for most people to get in the best shape of their lives. No Intermittent Fasting required. I know that because I’ve been in this business for 20 years and have helped a lot of clients achieve success in fat loss and improving health. Very few of them did any more than the trial fast, but all of them are taught those essentials. So, if you’re a beginner, please start with these.

However, if you’re a little further down the fitness path, I will say this. For a very specific demographic–people with fitness and exercise experience who also consider breakfast 15 minutes they’ll never get back–IF could be a very effective approach. Maybe even the best approach.

Just don’t tell Mom, okay?

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If you’re intrigued by Intermittent Fasting and want to learn more, Dr. Berardi has published an absolutely free e-book on the subject called Experiments with Intermittent Fasting. In the book, he gets into all the different fasting approaches he tried, including details of his exercise programs and his exact eating plans, as well as which ones could work best for you. There’s also a great section on nutrition best practices and self-experimentation.