Intermittent Fasting 101: The Basics And The Science For Beginners

Hey there, Vic here and today I have a guest post from John “Roman” Romaniello.  Roman is a New York City based personal trainer who has been featured in Men’s Health, Shape, and Good Morning America.  One of his specialties is stubborn fat loss through hormone optimization and one of his favorite tactics for getting those hormones in-line is intermittent fasting.

I’ve experimented with intermittent fasting myself with good results.  But my expertise on this subject is no where near the level of Roman’s.  And with that, I’ll let Roman take it away. . .

INTERMITTENT FASTING may well be the most discussed dietary concept on the Internet right now.

Like many other “breakout” diets, intermittent fasting (IF) is growing by leaps and bounds; however, unlike most of the other diets, IF is gaining ground despite that the practice challenges many long-help assumptions about nutrition.

In fact, practicing IF forces you to eat in direct opposition to those assumptions, and that—along with the results—it what’s generating all the buzz.

Before we get into the why and the how, let’s first discuss the basics of the what.

What is Intermittent Fasting?

The most accurate definition is the simplest one: IF is merely alternating intervals of not eating (fasting) with times where you are allowed to eat.

Or, to use IF parlance, you alternate a fasting period with a feeding window.  How long each will be varies depending on which “type” of IF programming you select—and there are several.

The differences come from expanding the fasting window.  The fasting period on specific plans can range from 16 hours all the way up to 36 hours (with several stops in between), and each of those specific plans will have benefits.

It’s also important to note that every one of us does some form of fasting, whether you realize it or not.  The least technical-while-still-being-accurate definition of fasting is simply “not eating,” so anytime you’re not eating, you’re fasting.

Most of us aren’t on a structured timetable of meals where the window of fasting is constant, so rather than fasting intermittently, we’re fasting haphazardly—and there’s no benefit there.

The exception for most people is sleep.  When you’re sleeping, you’re fasting; therefore most of us have a fairly rigid fasting period of 6-8 hours per night, until we eat in the morning.  It is for this reason, by the way, that our morning meal is called “breakfast,” as you are literally breaking your overnight fast.

Which brings me to my next point. . .

The Most Important Meal of the Day? Intermittent Fasting Science Tackles the Insidious Scourge of Breakfast!

Breakfast is sort of a hot topic in the IF world, and in fact seems to be the first point of contention for people looking in on intermittent fasting from the outside.  Don’t we need breakfast?

Intermittent Fasting proponents tend to say no…which flies in the face of much of the dietary advice coming from every authority from Registered Dietitians to MDs.  But the IF proponents… these dudes hate breakfast.

Here’s why: for years, we’ve been told that breakfast is the most important meal of the day.  In fact, many people are often scolded by their physicians for skipping breakfast—particularly people who are embarking on a plan to lose weight.

There is some credence here, by the way: a study conducted in 2008 showed that participants who ate a calorically dense breakfast lost more weight than those that didn’t.  The espoused theory for the results was that the higher caloric intake early in the day led people to snack less often and lowered caloric intake overall.

The value of that study has been questioned for many reasons, not the least of which is that despite the fact that roughly 90% of Americans eat breakfast, close to 50% of Americans are overweight.  If eating breakfast is the first step to weight loss, then something else is going wrong.

More evidence seems to support the breakfast idea, though. There are some epidemiological studies that show a connection between skipping breakfast and higher body weight.

However, the crux of the breakfast study is ultimately that a larger breakfast leads to lower overall caloric intake. That is, the argument for a larger breakfast ultimately boils down to energy balance; if that study is reliant on the position that weight loss comes down of calories in versus calories out, then the make up of the food shouldn’t matter.  But clearly, something else is going on.

The only real argument that the breakfast crowd has is insulin sensitivity.  As a very basic note on what this is and why this matters the more sensitive your body is to insulin, the more likely you are to lose fat and gain muscle.  Increasing insulin sensitivity almost always leads to more efficient dieting.

Getting back to it, supporters of eating breakfast declare that as insulin sensitivity is higher in the morning, eating a carbohydrate rich breakfast is going to have the greatest balance of taking in a large amount of energy without the danger of weight gain.

This brings us back to IF.  You see, insulin sensitivity isn’t higher “in the morning”; it’s higher after the 8-10 hour fasting periods you experience if you sleep.  Or more specifically, insulin sensitivity is higher when glycogen levels are depleted; as liver glycogen will be somewhat depleted from your sleeping fast.

Intermittent fasting takes that a step further: it seems that extending the fasting period beyond that 8-10 hours by skipping breakfast (and therefore further depleting glycogen) will increase insulin even further.

Insulin sensitivity is also increased post-exercise (due to further glycogen depletion in addition to other mechanisms), and so I feel it makes to most sense to compound benefits by training in a fasted state and then having your first meal after training.

Ultimately, this all means that there’s nothing special about breakfast and no need to eat first thing in the morning—the first meal you eat to break your fast will be exposed to the benefits of increased insulin sensitivity.

On the other hand, there’s nothing inherently evil about breakfast, either; that is, even if you practice some form of fasting, you can still eat breakfast.  Remember, the more important part is the length of the fast, not the time of the fast.  Skipping breakfast just happens to be the easiest way to implement a fast.

A discussion that mentions skipping breakfast—or any meal, really—will invariably lead into a discussion of meal frequency, which leads me to my next point.

On Frequency: Intermittent Fasting Crusaders Battle the Myth of Six Meals

And now we come to what seems that over the past 15-20 years, hundreds of diet books have been printed, and no two were identical.  In fact, some of them have been in direct opposition to one another.

Calorie-restrictive plans like Weight Watchers certainly don’t agree with plans like the Atkins diet, the first iteration of which allowed dieters to at all they want, as long as they kept carbs low.

Similarly, carb conscious plans generally call for products like yogurt or cottage cheese to be used as portable sources of protein, but many plans to reject dairy products altogether.

Despite the incredibly disparate natures of so many of these diets, the one thing that has been consistently suggested in most books published over the past 20 years is the frequency of meals.

If you’ve read a diet book, seen a nutritionist or hired a personal trainer at any point during that time, you’ve probably been told that in order to lose weight, you need to eat 5-6 small meals per day.  (Note: this suggestion is sometimes phrased as “3 meals and 2 snacks.”)

This style of eating, commonly referred to as the frequent feeding model, is popular with everyone from dieticians to bodybuilders, and has been repeated so often for so long that it’s generally taken as fact.

Which it isn’t.

In fact, the reputed benefits of eating small meals more often have never been scientifically validated.

The first and most commonly cited of these is that eating frequently “stokes the metabolic fire.”  Put less colloquially, the theory suggests that since eating increases your metabolic rate, the more often you eat, the more your metabolic rate will be elevated.  That’s true, but it doesn’t lead to more fat loss—in fact, it’s been scientifically borne out that there won’t be a difference at all.

When you eat, your metabolic rate increased because of the energy required to break down the food you’ve taken in.  This is called the Thermic Effect of Food, or TEF.  So, while you’re be experiencing energy expenditure due to TEF every time you eat, the net effect is no different regardless of how many times you eat, as long as the total amount of food is the same.

You see, TEF is directly proportional to caloric intake, and if caloric intake is the same, at the end of the day, there will be no metabolic difference between eating 5-6 meals or 2-3.  In fact, as long as the total calories are the same, you can eat ten meals or one meal, and you’ll still get the same metabolic effect.

Further, one study has shown that eating more frequently is less beneficial from the perspective of satiety, or feeling “full.”  Which means that the more often you eat, the more likely you are to be hungry—leading to higher caloric intake and eventual weight gain.

Intermittent Fasting guru Martin Berkhan has summarized this study, it’s meaning, and the effects of such things quite well, but suffice it to say that it seems people who eat larger meals less frequently take in fewer calories and are more satisfied doing so.

A smaller number of meals obviously fits well into fasting protocols—if you are condensing the amount of time you’re “allowed” to eat into a small window of 4-8 hours, having more than 2-3 meals becomes impractical at best and impossible at worst.

Calories, Hormones, and Eternal Life (Okay, Not Really): The Benefits of Intermittent Fasting

Obviously, above and beyond the debunking of long-believed myths, there are numerous benefits to Intermittent Fasting that make it so popular.

Firstly, as we’ve established thus far, people who practice IF eat less frequently.  In addition to feeling hungry less often, and more full when they do eat, these people benefit in terms of practicality and logistics.

After all, eating fewer meals means fewer meals and/or buying fewer meals.  In addition to saving you time (and, probably, money), this also means that you exposed to flavors less often, and are therefore less likely to get bored and eat something you shouldn’t.

We’ve also mentioned that eating less frequently tends to result in eating fewer calories overall, but that’s a pretty important point so it bears repeating: eating less frequently tends to result in eating few calories overall.

And speaking of caloric restriction: that brings us to another benefit.  IF plans that require full day fasting drastically reduce your calorie intake, so if you are using a style of IF which requires you to fast for 24 hours twice per week, you’re reducing your food intake by about 30%.  It’s not hard to see how that would lead to weight loss.

Going a little further, by restricting calories, you’re forcing the body to look elsewhere than the gut for energy, which can encourage cellular repair. That is, a cell will turn to its own damaged proteins for energy.  While that cycle would be bad in the long term, keep in mind you’re only fasting for “brief” periods; when you eat again the cell will use the new cell-stuff replace the old cell-stuff that’s been consumed.  All told, this phenomenon—which, again, stems from caloric restriction—can generally help prevent both disease and age.

For something more specific: one study out of the University of Utah showed that people who fasted just one day per month were 40% less likely to suffer from clogged arteries.

While there’s certainly a lot to be said for caloric restriction, it’s important to keep in mind that intermittent fasting isn’t just about eating fewer calories—there are also hormonal benefits that lead to improved body composition.

For starters, there’s the improved insulin sensitivity that comes with fasting, especially when paired with exercises, as we’ve covered; however, fasting has other hormonal benefits, including (but not limited to) an increase in the secretion of growth hormone (GH).

Growth Hormone has a myriad benefits—a discussion of which in full is beyond the scope of this writing—but for our purposes it’s enough to say that the more GH your produce, the faster you can lose fat and gain muscle.  Additionally, GH tends to offset the effects of cortisol, which is (in part) related to belly fat storage; so it seems likely that fasting can help you lose belly fat, at least indirectly.

Still not satisfied?  Well, if you need another benefit, fasting reduces inflammation as well, which can have implications for improved immunity as well as increased fat loss.

Wrapping Up: 

The most important thing to remember about Intermittent Fasting is that it isn’t a “diet” it’s a way of eating, a nutritional lifestyle that will allow you to reach your goals in an efficient and convenient manner, and then hold onto your physique once you achieve them.

And while IF isn’t for everyone, nor is it a perfect plan, it’s certainly an effective way to lose weight.

In addition to the hormonal benefits inherent in the practice, you’ll also feel more satisfied with your food, feel hungry less often, and probably save some money on food!

Moreover, you may live longer…if, you know, you’re into that.

So, even if you never try IF, you can at least appreciate that it’s forced the fat loss industry at large to re-evaluate the “truths” we tend to cling to.

Perhaps it’s for this reason that Intermittent Fasting seems to be generally received with appreciation and acceptance, while low carb diets, Paleo eating and absurdities like the “Twinkie diet” all have people on both sides of the line either praising or lambasting them.

That is, Intermittent Fasting is well received once people see the research.  And there’s a simple reason for that: it works.


Thanks, Roman!  Over the course of the past few years I’ve often used a 20 – 24 hour fast once per week to aid fat loss.  Currently I’m experimenting with training in a fasted state and limiting my overall “feeding window” to eight hours each day.  From my own experience, I know that intermittent fasting can be an effective fat loss tactic.

Have you tried intermittent fasting?  What were your results?  Let me know in the comments below.

Train Hard!

~ Vic


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10 Responses to “Intermittent Fasting 101: The Basics And The Science For Beginners”

  1. Craig says:

    I use to eat one or 2 times a day. But i put on weight. I have found on the foods you picked was very good for change. F or now i dont get acidy and bloaded any more in my tummy. I fill much better, pasing blood tests at doc’s. I have breaky every morning now, eggs unions and tomatoes. morning tea with 1 peace of friut. lunch salid with crushed almonds so i get the potein to give filling. afternoon 1 friut water or tea. tea time lots of veg fish or meat to go with it low fat. I rotate fish and meat every day so i get all my vito’s. Then wait till next day to eat. I find by if you eat, right, by eating every 2 to 3 hours in day time. the body wont store up fat. For it knows it will get a meal. If you starve, it will store up. the body is smart, it will make back up.With fat.
    Oh, I got the email on fish tablets and your right there a must they do help loss weight. I,ve lost 4 kilo so far in 1 week. love the food. Yum yum.
    Hope it helps


  2. Rick says:

    I have tried intermittent fasting on two occasions and both times I had the same experience. It was incredibly hard to do, I experienced a level of hunger that had me literally dreaming of food, and it did not help with my weight loss in any discernable way. I found that I made up for the calories I didn’t eat when fasting by eating more when it was finally time to chow down.
    Having said that there’s an excellent article about the anti-inflammotory benefits of IF here:

    If I were to try it again it would be for this reason – not to try and reduce caloric intake.


  3. Alison says:

    I find the conversation enlightening and interesting. It certainly challenges you think about what and how you eat. That being said, how do you Vic define “fasting”. Do you permit yourself to only consume water during the awake fasting hours?


    vicmagary Reply:

    I personally will drink water, black coffee, or unsweetened tea (often herb tea).


  4. Cyndi says:

    Moderation is the key for me – and also a better definition of fasting? are we fasting from solid foods? allowed to drink protein shakes or juices, tea or coffee — or only H2O? that will make a huge difference. I have found that if I can have coffee, tea or juice while fasting from solid foods – things aren’t so difficult. I have also found a natural tendency to fast. Some days, especially on a Saturday or Sunday, I will get up, have my coffee, go exercise, and then eat. So essentially fasting for a good 16 hours most times. I believe it does extend your life and does allow you to appreciate the real feelings of hunger which many people “forget”. This in turn makes me really appreciate good food and want to eat some good nutritious food – which my body then seems to be craving. My two cents…


  5. Regina says:

    When I was in college (several yrs ago) I went on a weight loss plan (my own) of eating one meal a day. I could eat whatever I wanted and didn’t count calories but only ate once a day then about every three or four days I totally fasted. I lost 35 lbs but I felt like complete crap! I was constantly shaky and had no energry at all to exercise. Lost weight, no doubt, but no way do I believe it was “healthy” to do it that way because of the way I felt. And, of course, after a few years the weight all came back because I could not sustain that. Years later I went on another weight loss plan of eating three meals a day and exercising in the eve right after eating dinner. I was running 5 miles a day and eating 1200 to 1500 calories per day. Again, lost the 35 to 40 lbs. This time I felt great, lots of energy. I have been a yo yo dieter, I got out of my exerciser routine and then dropped it all together and over three years but the 40 lbs back on again :( In my opinion the exercise is a big part of it, I was maintaining as long as I was exercising. Almost 2 mnths ago I was sick of myself and started the 31 Fat Loss Cure and I love it. I have lost about 20lbs and I am working out again. If I fast, I have NO ENERGY and either can’t exercise at all or only half (butt) do it. That is the main reason I exercise in the eve and not the morning. I usually have my last meal around 6:00pm go exercise, then eat nothing else. It is usually about 8:30 or 9:00am that I eat breakfast the following morning so I guess in a way I am “fasting” more then 12hrs everyday. I can just say for me, fasting for a day a week just would never work for me and I just can’t believe it is healthier for me because I feel so terrible if I do it. Very interesting concept though.


  6. Paul says:

    I have found the dinner to dinner fast easier (though not necessarily easy). I fast after dinner on Sunday until dinner on Monday (actually my rule is 5:00PM), so basically a 22 hr fast. I appreciate this information as it will now be even easier because of these health benefits that I was unaware of!


  7. Sandy Cooper says:

    I have done a variety of fasts over the years (3 days water only, 24 hour water only, 21-day fruit and veg fast, 40-day fruit and veg fast), but I do them for spiritual reasons. I do feel that IF has both health and spiritual benefits, otherwise, God would not have directed people to fast. Besides, simply telling my body “no” is a great exercise in self-control and keeps me from becoming a spoiled brat :) .

    Currently, I’m working through P90X2 which has 2 rest days built in to each week. I am considering a total or partial fast on one of my rest days each week to increase the rate of fat loss. I don’t have a ton to lose, but I’d like to accelerate the process while working through this physically challenging program.

    I appreciate all the information provided in this post. Very, very helpful.



  8. Carroll says:

    Our chuch declared a 40 day fast several years ago and I will tell you, it was the hardest thing I ever did! In addition, there was to be no meat to the fast. Basically, water, juice, black coffe or tea during the day, and a big meal of beans or all kinds, fruits and veggies early in the evening. Without almost any exercise, most of us lost 20 or more pounds in the 40 days. I don’t belong to that church anymore, but I can remember how good I started feeling near the end. Fasting is now hard for me because it messes with my blood sugar and gives me headaches.

    Thanks for the information.



  9. Ron says:

    I can imagine that fasting is just easier for some people and harder for others. Most of the time I don’t need to loose much weight if any, so I don’t know what it is like to loose a lot of weight. Years ago I went on a one month Spirulina fast during which time I consumed one teaspoon of Spirulina powder in a glass of fruit juice, three times a day. I could drink as much water or juice as I wanted. I had no difficulty with it at all other than the memory of the taste of food that I missed. I lost about 5 to 10 pounds and otherwise was in a state of lightness and could continue working the whole time. Since then I have tried to do it serveral other times but only got to about the 15th day and gave up, not because I was hungry but because of the desire to taste food.
    Last August I took 3 weeks off to successfully complete a 3 week conversion to Living on Light. It would take too long to explain here so anyone interested can just Google it. Basically it is the understanding and belief that we really to not need food at all to live. Many people have converted away from eating food and I wanted to try it out. During the whole 3 weeks I ate absolutely no food. For the first week I also had no water but was allowed to drink diluted water and juice during the last two weeks. This is definitely not something to try without thorough research and preparation as it could be life threatening without a proper understanding.
    My point is, that as a result of this experiment I now personally have a completely different understanding of what food does for us. I went back to eating after about 4 or 5 weeks for a coulpe of reasons. My weight wasn’t stabilizing fast enough for me, as I thought it should, and secondly, it is a real hassle socially when you are the only one not eating at an event and having to explain why all the time. I did not feel hungry.

    At the moment I am still trying to find a good balance of Bikram Yoga, your weight exercises and days off for rest. I still enjoy the rest days the most.


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