The Beginner’s Guide to Intermittent Fasting

“…But Tony the Tiger tells us that breakfast is the most important meal of the day!”

This rule has become so commonplace throughout the health and fitness community that it’s readily accepted as fact:

“Want to lose weight? Make sure you start off with a healthy breakfast, so you can get that metabolism firing first thing in the morning!  Eat breakfast like a king, lunch like a prince, and dinner like a pauper.”

“Want to lose more weight? Make sure you eat six small meals throughout the day so your metabolism stays operating at maximum capacity all day long”.

There are even studies that show those that eat earlier in the day lose more weight than those who ate later in the day or skipped a meal.

So, eat breakfast to lose weight and obtain optimal health.  Case closed…right?

Maybe you’re not getting the whole story. As skeptics, what we need to ask: what if there’s science and research that promotes SKIPPING BREAKFAST (the horror! blasphemy!) for optimum efficiency, maximum muscle retention, and body fat loss?

After firmly being on “Team Breakfast” for 28 years of my life, I’ve skipped breakfast for the past three months and might never go back to eating it.

I want to share with you a concept about skipping breakfast (and other meals), and how your health will benefit as a result.

Tony ain’t gonna be happy, but today we’re talking about intermittent fasting.

This is a topic that is very controversial, as it turns a LOT of conventional wisdom on its head. This is why this article is filled with more sources and citations than Jim Carrey’s glove compartment.

What is intermittent fasting?


Intermittent fasting is not a diet, but rather a dieting pattern.  

In simpler terms: it’s making a conscious decision to skip certain meals.

By fasting and then feasting on purpose, intermittent fasting means eating your calories during a specific window of the day, and choosing not to eat food during the rest.

Now, there are a few different ways to take advantage of intermittent fasting:

  • Regularly eat during a specific time period.  For example, only eating from noon-8 PM, essentially skipping breakfast.  Some people only eat in a 6-hour window, or  even a 4-hour window.  
  • Skip two meals one day, taking a full 24-hours off from eating.  For example, eating on a normal schedule (finishing dinner at 8PM) and then not eating again until 8PM the following day.

Now, you might be thinking: “okay, so by skipping a meal, I just eat less than normally overall, and thus I will lose weight, right?”  

Well, that’s partly true.  

Yes, by cutting out an entire meal, you are able to eat MORE food during your other meals and still consume a caloric deficit (which is an important for losing weight).  

However, as we already know that not all calories all created equal, the timing of meals can also influence how your body reacts.  

How does intermittent fasting work?


With intermittent fasting, your body operates differently when “feasting” compared to when “fasting”:

When you eat a meal, your body spends a few hours processing that food, burning what it can from what you just consumed.   Because it has all of this readily available, easy to burn energy in its blood stream (thanks to the food you ate), your body will choose to use that as energy rather than the fat you have stored.  This is especially true if you just consumed carbohydrates/sugar, as your body prefers to burn sugar as energy before any other source.

During the “fasted state,” your body doesn’t have a recently consumed meal to use as energy, so it is more likely to pull from the fat stored in your body, rather than the glucose in your blood stream or glycogen in your muscles/liver.

Burning fat = win.

The same goes for working out in a “fasted” state.  Without a ready supply of glucose and glycogen to pull from (which has been depleted over the course of your fasted state, and hasn’t yet been replenished with a pre-workout meal), your body is forced to adapt and pull from the only source of energy available to it: the fat stored in your cells!

Why does this work?  Our bodies react to energy consumption (eating food) with insulin production.  Essentially, the more sensitive your body is to insulin, the more likely you’ll be to use the food you consume efficiently, which can help lead to weight loss and muscle creation.

Along with that, your body is most sensitive to insulin following a period of fasting. 

Your glycogen (a starch stored in your muscles and liver that your body can burn as fuel when necessary) is depleted during sleep (fasting), and will be depleted even further during training, which can further increase insulin sensitivity. This means that a meal immediately following your workout will be stored most efficiently: mostly as glycogen for muscle stores, burned as energy immediately to help with the recovery process, with minimal amounts stored as fat.

Compare this to a regular day (no intermittent fasting).  With insulin sensitivity at normal levels, the carbs and foods consumed will see full glycogen stores, enough glucose in the blood stream, and thus be more likely to get stored as fat.

Not only that, but growth hormone is increased during fasted states (both during sleep and after a period of fasting).  Combine this  increased growth hormone secretion, the decrease in insulin production (and thus increase in insulin sensitivity), and you’re essentially priming your body for muscle growth and fat loss with intermittent fasting.

The less science-y version: Intermittent fasting can help teach your body to use the food it consumes more efficiently.  For many different physiological reasons, fasting can help promote weight loss and muscle building when done properly.  

But why does every health book say “6 small meals?”

small plate

There are a few main reasons why diet books recommend six small meals:

1) When you eat a meal, your body does have to burn extra calories just to process that meal.  So, the theory is that if you eat all day long with small meals, your body is constantly burning extra calories and your metabolism is firing at optimal capacity, right? Well, that’s not true.  Whether you eat 2000 calories spread out throughout the day, or 2000 calories in a small window, your body will burn the same number of calories processing the food.  So, the whole “keep your metabolism firing at optimum capacity by always eating” sounds good in principle, but reality tells a different story.

2) When you eat smaller meals, you’re less likely to overeat during your regular meals.  I can definitely see some truth here, especially for people who struggle with portion control or don’t know how much food they should be eating.  However, once you educate yourself and take control of your eating, I would argue most people find that eating six times a day is very prohibitive and requires a lot of effort.  Along with that, because you’re eating six small meals, I’d argue that you probably never feel “full,” and you might be MORE likely to eat extra calories during each snack.

Although grounded in seemingly logical principles, the “six meals a day” doesn’t work for the reason you think it would (#1), and really only works for people who struggle with portion control (#2).

If we want to think back to the caveman days, we’d have been in serious trouble as a species if we had to eat every three hours.  Do you think Joe caveman pulled out his pocket sundial six times a day to consume his equally portioned meals?  Hell no!  He ate when he could, and his body adapted to still function optimally during the rest of the day.

A recent study (highlighted by the New York Times) has done a great job of challenging the “six-meals-a-day” technique for weight loss.  

Martin from LeanGains points out two important quotes from the study:

“…The premise underlying the present study was that increasing meal frequency would lead to better short-term appetite regulation and increased dietary compliance; furthermore, it was hypothesised that these predicted beneficial effects of increased meal frequency could have resulted from more favourable gut peptide profiles, potentially leading to greater weight loss. Under the conditions described in the present study, all three hypotheses were rejected.”

“…We had postulated that increasing meal frequency would enhance the compliance to the energy restricted diet thus leading to greater weight loss, an effect possibly mediated by increased fullness. The present results do not support this hypothesis.”

Remember, the type of food you eat matters. Meal frequency is not nearly as important as the quantity and quality of food consumed.  This study reached similar conclusions.

Why intermittent fasting?

IF fast plate

Because it works.  Although we know that not all calories are created equal, caloric restriction plays a central role in weight loss.  When you fast (either for 16 hours per day, or 24 hours every few days), you are also making it easier to restrict your caloric intake over the course of the week.  This will give your body a chance to lose weight as you’re simply just eating less calories than you were consuming before.

Because it simplifies your day. Rather than having to prepare, pack, eat, and time your meals every 2-3 hours, you simply skip a meal or two and only worry about eating food in your eating window.

It requires less time (and potentially money). Rather than having to prepare or purchase three to six meals a day, you only need to prepare two meals.  Instead of stopping what you’re doing six times a day to eat, you simply only have to stop to eat twice.  Rather than having to do the dishes six times, you only have to do them twice. Rather than having to purchase six meals a day, you only need to purchase two.

It promotes stronger insulin sensitivity and increased growth hormone secretion, two keys for weight loss and muscle gain.  This was already explained in the previous section with relevant sources, but intermittent fasting helps you create a double whammy for weight loss.

Plus, Wolverine does it.

What are the drawbacks with intermittent fasting?


In my own experimentation, I have found very few negative side effects with Intermittent fasting.  

The BIGGEST issue I’ve found, and the biggest concern most people have, is that intermittent fasting will lead to lower energy, focus, and the “holy crap I am hungry” feeling during the fasting period.  People are concerned that they will spend all morning being miserable because they haven’t consumed any food, and thus will be miserable at work and ineffective at whatever task it is they are working on.

Yes, the initial transition from EATING ALL THE TIME, to intermittent fasting can be a bit of a jolt to the system. However, once you get through the transition, your body can quickly adapt and learn to function just as well only eating a few times a day:

This study explains that in participants after 48-hours of fasting, “cognitive performance, activity, sleep, and mood are not adversely affected in healthy humans by two days of calorie-deprivation.”

“So why do I feel grouchy when I’m not eating breakfast?” In this nerd’s humble opinion, a good portion of the grumpiness is a result of your eating habits. If you eat every three hours, your body will start to get hungry every three hours as it learns and becomes used to expecting (and receiving) food every three hours. If you eat breakfast every morning, your body is expecting to wake up and eat food.

It turns out, quite a bit of it is mental.

Once you retrain your body to NOT expect food all day every day (or first thing in the morning), these side-effects become less of an issue (thanks to a substance our bodies produce called Ghrelin).

Think about it in caveman terms again.  We certainly found ways to survive during periods of feast and famine, and that remains true today.  It actually takes our bodies about 84 hours of fasting before our glucose levels are adversely affected.  As we’re talking about small fasts (16-24 hour periods), this doesn’t concern us.

AN IMPORTANT CAVEAT: Intermittent Fasting can be complex for people who have issues with blood sugar regulation, suffer from hypoglycemia, have diabetes, etc.  If you fit into this category, I highly recommend you check with your doctor or dietitian before adjusting your eating schedule.

I believe more research needs to be done for these particular cases and thus would recommend you do what works best for YOU.

Can I build muscle and gain weight while intermittent fasting?

muscle hypertrophy


In fact, I have been intermittent fasting for the past three months or so while building muscle, with minimal increase to my body fat percentage.  I still eat the same number of calories I was consuming before, but instead of eating all damn day long, I condense all of my calorie consumption into an eight hour window.

  • 11 AM Work out with heavy strength training in a fasted state.
  • 12 PM Immediately consume 1/2 of my calories for the day (a regular whole-food meal, followed by a massive Calorie Bomb Shake.)
  • 7 PM Consume the second portion of my calories for the day in a big dinner.
  • 8 PM – 12 PM the next day: Fast for 16 hours.

This method has been borrowed from one of the best resources on intermittent fasting and muscle building on the internet: Lean Gains.

In a different method, my friend Nate Green packed on a crazy amount of muscle while fasting for a full 24 hours on Sundays.  

I’m not kidding when I say this has revolutionized how I look at muscle building and fat loss.  Ultimately, this method flies in the face of the typical “bulk and cut” techniques of overeating to build muscle (along with adding a lot of fat) before cutting calories to lose fat (along with some muscle) and settling down at a higher weight.

I prefer this method to the bulk-and-cut technique for a few reasons:

  • There’s far less of a crazy swing. If you are putting on 30 pounds and then cutting 25 to gain 5 lbs of muscle, your body is going through drastic swings of body mass. Your clothes will fit differently, you’ll have different levels of definition, and your body will wonder what the hell is going on.
  • You’re consuming less food and thus spending less money.  Rather than overeating to put on 1 pound of muscle and 4 pounds of fat in a week or two, you’re aiming to eat exactly enough to put on 1 pound of muscle without adding much fat on top of it.  Yeah, it’s a delicate balance, but there’s far less swing involved. You are just slowly, steadily, and consistently building muscle and strength over many months.
  • There’s never a need to get “vacation-ready”: we all want to look good naked, right?  When you are just adding muscle, you don’t need to worry about getting your body ready before by drastically altering your diet (going on a miserable crash diet for a month). I like Anthony Mychal’s technique of never being more than two weeks away.  Keep your body fat percentage low, build strength and muscle, and if you happen to notice your body fat creeping up, cut back on the carbs. Within two weeks you should be back at your preferred body fat percentage and can continue the muscle building process.

Does intermittent fasting have different effects on men and women?

boy girl

Yes, intermittent fasting does affect men and women differently.

This article over on Paleo For Women goes extensively into the negative effects of intermittent fasting for women.

This article on Mark’s Daily Apple does a fantastic job of breaking down the differences between men and women and how they are affected by intermittent fasting, ultimately explaining:

  • “One study, which I’ve cited before as evidence of a benefit to fasting, found that while IF improved insulin sensitivity in male subjects, female subjects saw no such improvement. In fact, the glucose tolerance of fasting women actually worsened. Ouch.
  • Another study examined the effect of alternate day fasting on blood lipids. Women’s HDL improved and their triglycerides remained stable; men’s HDL remained stable and their triglycerides decreased. Favorable, albeit sex-specific results.
  • Later, both obese men and women dropped body fat, body weight, blood pressure, total cholesterol, LDL cholesterol, and triglyercides on a fasting regimen. These people were obese, however, and perimenopausal women were excluded from the study, so the results may not apply to leaner people or women of reproductive age.”

Long story short: Yes, men and women will have different experiences with intermittent fasting; we’re all unique snowflakes (yep, even you), and your body will be affected by intermittent fasting differently than the person next to you.

My best advice?  Give it a shot, track your results, and see how things go!

Questions about intermittent fasting


“Won’t I get really hungry?”  

As explained above, this is generally a result of the habits you have built for your body.  If you are constantly eating or always eat the same time of day, your body can actually learn to prepare itself for food by beginning the process of insulin production and preparation for food.  After a brief adjustment period, your body can adapt to the fact that it’s only eating a few times a day.

Remember, your body’s physical and cognitive abilities aren’t diminished as a result of fasting.

“Where will I get my energy for my workouts?  Won’t I be exhausted and not be able to complete my workouts if fasting?” 

This was a major concern of mine as well.  And for my first workout or two, it was very weird to not eat a heavy carb meal before training.  However, after a few sessions, I learned that my body could certainly function (and even thrive) during my training sessions despite not eating a pre-workout meal.

As Mark’s Daily Apple states:

Fasted training can actually result in better metabolic adaptations (which mean better performance down the line), improved muscle protein synthesis, and a higher anabolic response to post-workout feeding (you’ll earn your meal and make more muscle out of it if you train on an empty stomach).

That being said, I’m currently experimenting with a pre-workout BCAA supplement to see the effect it has on muscle creation.  So far, so good, though I’m not sold on the necessity of the supplement yet.  I’ll keep you posted :)

“I like the idea of fasted training, but I work a regular 9-5 and can’t train at 11AM. What am I supposed to do?”

Martin from LeanGains lays out a few different options for you, depending on your training schedule.  The best advice is to not freak out and overanalyze unless you are an elite athlete concerned with the absolute optimal performance at all time.

If you’re just a normal guy or gal looking to drop a few pounds and get stronger, do the best you can.

“Won’t fasting cause muscle loss?”  

Another big concern of mine, but it turns out…it was unfounded.  We’ve been told by the supplement industry that we need to consume 30 g of protein every few hours, as that’s the most amount of protein our body can process at a time.  Along with that, we’ve been told that if we don’t eat protein every few hours, our body’s muscle will start to break down to be burned as energy.

Again, NOT TRUE!  This study shows that our bodies are quite adept at preserving muscle even when fasting, and it turns out that protein absorption by our body can take place over many many many hours. Protein consumed in a shorter period of time has no difference on the body compared to protein spread throughout the day.    

“What about my body going into starvation mode from not eating?” 

Now, the thought process here is that when we don’t feed ourselves, our bodies assume calories aren’t available and thus choose to store more calories than burning them, eliminating the benefits of weight loss with fasting. Fortunately, this is NOT true.

As Martin from LeanGains so eloquently explains (as you can tell, he’s good at this stuff):

“The earliest evidence for lowered metabolic rate in response to fasting occurred after 60 hours (-8% in resting metabolic rate). Other studies show metabolic rate is not impacted until 72-96 hours have passed.

Seemingly paradoxical, metabolic rate is actually increased in short-term fasting. For some concrete numbers, studies have shown an increase of 3.6% – 10% after 36-48 hours (Mansell PI, et al, and Zauner C, et al).  Epinephrine and norepinephrine (adrenaline/noradrenaline) sharpens the mind and makes us want to move around. Desirable traits that encouraged us to seek for food, or for the hunter to kill his prey, increasing survival. At some point, after several days of no eating, this benefit would confer no benefit to survival and probably would have done more harm than good; instead, an adaptation that favored conservation of energy turned out to be advantageous.”

“This sounds crazy, I’m not gonna do it.”

That’s cool.  Are you losing body fat, building muscle, and getting a clean bill of health from your doctor?  If you can say yes to those things, AWESOME. Keep doing what you’re doing, because it’s working.   

However, if what you’re doing ISN’T working, or you’re not getting the results you were hoping for, why not give it a chance?  Hopefully the dozens of studies at least peak your curiosity.  Self-experimentation is the best way to determine WHAT methods work for you.

Tips and tricks about Fasting 

hungry ant

Don’t freak out.  Stop wondering: “can I fast 15 hours instead of 16?” or “what if I eat an apple during my fasted period, will that ruin everything?”  Relax.  Your body is a finely tuned piece of machinery and learns to adapt.  Everything is not as cut and dry as you think.

If you want to eat breakfast one day but not another, that’s okay.  If you are going for optimal aesthetic or athletic performance, I can see the need to be more rigid in your discipline, but otherwise…freaking chill out and don’t stress over minutiae.

Expect funny looks.  A few weeks back I had a number of friends staying with me, and they were all completely dumbfounded when I told them I didn’t eat breakfast anymore.  I tried to explain it to them but received a bunch of blank stares.  Breakfast has become so engrained in our culture that NOT eating it sounds crazy.  You will get weird looks from those around you…embrace it.

Stay busy.  If you are just sitting around thinking about how hungry you are, you’ll be more likely to struggle with this.  For that reason, I time my fasting periods for maximum efficiency and minimal discomfort:

  • My first few hours of fasting come after consuming a MONSTER meal, where the last thing I want to think about is eating.
  • When I’m sleeping: 8 of my 16 hours are occupied by sleeping.  Tough to feel hungry when I’m dreaming about becoming a Jedi.
  • When I’m busy: After waking up, 12 hours of my fasting is already done.  I spend three hours doing my best work (drinking green tea and listening to PM, which is exactly what I’m doing while writing this article!), and then comes my final hour of fasting: training.

I don’t have time to think about how hungry I am, because I keep my brain constantly occupied!

Zero-calorie beverages are okay.  As previously stated, I drink green tea in the morning for my caffeine kick while writing.  If you want to drink water, black coffee, or tea during your fasted period, that’s okay.  Remember, don’t overthink it – keep things simple!

Track your results, listen to your body:  

  • Concerned about losing muscle mass?  Keep track of your strength training routines and see if you are getting stronger.
  • Buy a cheap set of body fat calipers and keep track of your body fat composition.
  • Track your calories, and see how your body changes when eating the same amount of food, but condensed into a certain window.

Everybody will react to intermittent fasting differently; I can’t tell you how your body will react.  It’s up to you to listen to your body and see how making these adjustments change your body.

Don’t expect miracles.  Yes, intermittent fasting can potentially help you lose weight, increase insulin sensitivity and growth hormone secretion (all good things), but it is only ONE factor in hundreds that will determine your body composition and overall health.  Don’t expect to drop to 8% body fat and get ripped just by skipping breakfast. You need to focus on building healthy habits, eating better foods, and getting stronger.

This is just one tool that can contribute to your success…

To sum it all up


Intermittent fasting can potentially have some very positive benefits for somebody trying to lose weight or gain lean body mass.

Men and women will tend to have different results, just like each individual person will have different results.  The ONLY way to find out is with self-experimentation.

There are multiple ways to “do” intermittent fasting:

  • Fast and feast regularly: Fast for a certain number of hours, then consume all calories within a certain number of hours.
  • Eat normally, then fast 1-2x a week: Consume your normal meals every day, then pick one or two days a week where you fast for 24 hours.  Eat your last meal Sunday night, and then don’t eat again until dinner the following day.
  • Fast occasionally: probably the easiest method for the person who wants to do the least amount of work.  Simply skip a meal whenever it’s convenient. On the road? Skip breakfast.  Busy day at work? Skip lunch.  Eat poorly all day Saturday?  Make your first meal of the day dinner on Sunday.

Remember: One of the Rules of the Rebellion is to QUESTION EVERYTHING.  If this seems like something you’d like to try, give it a shot. If it sounds crazy to you, ask yourself why you think it sounds crazy, and do your own research and experimentation before condoning/condemning it.

I’d love to hear from you:

  • What are your questions with intermittent fasting?  
  • What are your concerns?
  • Have you tried intermittent fasting?
  • Have you had success with it, either with muscle gain or weight loss?

Thanks for leaving your comment, I’m excited to get the conversation started.


PS: We’re fans of Intermittent Fasting, which is why its part of the Nerd Fitness Academy, our online training course that is helping over 4000 superheroes-in-training get fit, healthy, and happy.  Come on and join us!

PPS: Added an important caveat:  If you are somebody who has blood sugar regulation issues (diabetes, hypoglycemia, etc.), I strongly recommend you discuss with your doctor or medical professional before making changes to your diet.  Remember, question everything!


Photo Source: seal mouth, tony the tiger, anatomy, cog, small plates, apples, fridge, ant, boy girl, kiwi

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  • fiuza78

    I usually start after a very big meal. For example, if I go out to dinner and have a big meal I might try a 24h fast from that. I usually do it after lunch or dinner. It is easier if you do it after a big fatty meal.

  • fiuza78

    Try both. Pick one for 1 months and then the other one for another month. Then pick the one you enjoyed the most!


    Soo….. I take it a BPC doesn’t count as fasting in the morning huh? lol

  • fiuza78

    If you add butter, no!

  • Big Mike

    I’ve been doing IF for just under 3 months and not counted a single calorie. Lost 4 and a half inches from my waist (41 and a half down to 37) while seeing continual strength gains (from 3 to 7 pull ups and 3 to 9 dips). I don’t think counting calories is important, just commiting to the IF, eating real healthy foods (pretty much just been eating meat, nuts and vegetables with the occasional bit of fruint) and regular exercise. Haven’t been targettinf muscle growth but I can definitely see gains in my back, arms and upper legs (still a bit flabby on my chest and gut).

  • Fitness

    I’m taking pre workout c4 it has 5 calories.. Will that break my fasting stage? I train while fasted


    Yesterday, I stopped eating at 7:00 p.m., and didn’t eat anything until 7:00 a.m. .. is this considered IF? I lost a pound this morning, so I’m going to stick with it.

  • fiuza78

    No, it won’t break your fasting! I suggest you try to skip the C4. It’s so much chemistry… I wonder what it will do in the long run, like taking it for a few years.
    I used to use pre-workout for 1 year, and I dont use any now and I didnt see much difference on my strength. When you move to a low-carb diet your energy levels should go up!

  • fiuza78

    Yes. It is a 12 hour fasting.
    When you get used to it, try to move to 13 hours and eventually try the 14 hours – 16 hours window! You will get the most benefits from it!

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  • Evangelos Mylonas

    Seriously considering giving this a go. One major concern though; my blood iron is very low and I’ve been fine-tuning my diet to get my levels back to normal. How would IF affect mineral/vitamin deficiencies in general?

  • fiuza78

    It probably wont affect it as long as you eat plenty of veggies and leafs on lunch and supper!

  • Carys Thistlethwaite

    Thank you so much for all of the advice in the article! I truely appreciate it :)

  • Monika

    What about skipping dinner instead of breakfast? And fasting from 6pm-10am? Is there a difference in terms of impact?

  • fiuza78

    That work as well!

  • Niccole Talmadge

    I’m so excited about IF!!! I’m diabetic and my numbers are all over the place even with having green smoothies(mostly green). Since fasting I have seen a dramatic change in my life! I started out being nervous, not sure if I would be able to complete a full 16 hrs. I found that the fast leveled my glucose to the point where I didn’t need my morning medicine. I’m also able to do my cardio with full energy. I can also feel the surge of energy when my body pulls from my fat reserves(thats my breakfast). Post workout I have an isopure shake, then a green smoothie followed by dinner. I’m extremely suprised bc I’m a huge sugar monster but I have not craved any sweets or my fav carbs. Fasting has also regulated my glucose to the point that I don’t need to take my evening dose either! I have been so suprised at my results that I have began to do up to 19hr fastings so far. My only question is when the body begins to burn fat does the glucose elevate bc I have noticed a 10 point increase before/after workouts and I was not sure if my fat is full of sugar and thats where the elevation comes from

  • Luke H MacDonald

    Great article, great site! I’m 34, definitely a nerd (PhD – need I say more?) and have always reguarly excercised, but 2 weeks ago I began focusing on building strength because I was inspired by the Wolverine movies (again, nerd), and I came here for info on intermittent fasting. I would like feedback about my current eating/workout schedule.

    12pm-8pm eating with fasting overnight works best with my job. I lift for 1 hour 5 days per week at 6:30 am and do Bikram yoga for 90 minutes three days at 5 or 6 pm.


    1. I understand it’s best to lift in a fasted state, which kicks in ~12 hours after eating. So i’m lifting before the fasting truly starts. Is that a problem?

    2. I also hear that it’s best for muscle growth to eat protein right after a workout, but in my current setup I’m not eating for 4.5 hours after finishing. I’m worried this could inhibit growth or could even lead to muscle loss as my body metabolizes itself after a workout.


  • wah

    im six months late but this is my first ever nerd fitness post.
    I used IF nearly 2 decades ago (not realising). I was working nights and stopped eating at about 3 am sometimes 430 then finished work went home and later to bed not eating again then got up and either went to cricket or football training 3 days a week or pumped a little iron about 40 mins the other 3 days. I ate flat out the rest of my time 5 sandwiches hot dog and chips 2 dinners and could not put on any weight (less than 2 kgs in 8 months) but i more than doubled what i could lift in every non leg exercise. My mate who i was working out with made much slower progress (almost identical starting point age height) and started to get a podgy tummy and accused me of sucking my guts in and doing extra workouts (both taken as complements). I never thought much of this until a couple of years ago i came across a lad i played some cricket with built like a kelvin klein underwear model who insisted he never lifted any weights (no breakfast and phyical job). Since then i have come across so many other examples and started to wonder. I the watched a documentry about a month ago and searched the net came across this site

  • Steve Roncho

    Thanks for the info. I got turned on to this diet after watching an interview with Hugh Jackman (of all things) on his preparation for the “Wolverine” movies. But he was taking in like 4k -6k calories a day. I wont be doing that. I’ve been doing the 16hr fast for a week with ok results. I work out hard in the mornings and sometime that can be rough. My biggest cheat is milk in my coffee in the morning. Sometime I wake up hungry and have trouble getting back to sleep. Ive found that another swig of milk helps coat my stomach and nurses me back to sleep.
    Overall my form is not perfect yet.

  • Hernan

    Thanks a lot for this article, I want to say it helped in saving my life. After the Dr. told me i was pre-lots of things. I told the Dr. I didn’t want to be on pills so she said you can still fix it, I’ll see you in 3 months. I was told to watch the documentary Eat, Fast, live longer, from a co-worker. After watching the documentary i did some more research stumbled upon this article and decided to give it a shot. Well 3 months later Dr. was impressed with the blood work, I don’t need to be taking pills. I’m down 45 lbs, in 7 months and still going. Thanks a lot for the article. Any new updates?

  • Jessy

    Hi, i just want to have an idea of what can I eat in my window??

  • April

    I’ve scoured all the fasting stuff I can find, and can’t find a solution to my problem. I adapted to fasting pretty easily, in terms of not
    feeling hungry or tired all the time, but it also seems like my hunger comes right back at full
    force *after* I finally eat again, like the food primes my system to go
    back to its usual hungry-tired-eat cycle, which makes it harder to stick
    with a fasting plan. It’s actually easier for me to eat nothing all day, then
    have a high-protein, low-carb meal right
    before bed and sleep through the hunger spike, but I know doing this every day isn’t
    healthy as a longterm plan. I can’t even imagine doing alternate day fasting, or doing a 5/2 plan, because it would mean going through ‘food withdrawal’ hunger and grouchiness all over again every week. What do you do to avoid the hunger spike?

  • Dan Halverson

    So that’s what it is. I didn’t read the whole article when you first wrote it but now I did. And now I understand.
    Turns out I’ve intermitently fasted throughout my whole life! And, now that I understand what it is, I can say that I like intermittent fasting.

  • Jake

    I experimented with a few types of IF and wrote about it on wordpress. Is it bad for me? :

  • Isis

    Hi am looking into intermittent fasting. Is it possible to eat 2500calories in one meal and if so how do you go about the type of food to maximise this? Or is it possible to split the calories into two different meals a day?

  • Kevin

    I was turned on to intermittent fasting a few months ago and ran across this article and decided to give it a read. I love intermittent fasting and I’m glad there are nooby weight loss articles like this availble for us lard asses trying to make a change.

  • Katherine

    Question: does there have to be a specific routine for intermittent fasting? I tend to simply forget to eat until my stomach starts growling (which usually takes a few days) or I start getting dizzy (which isn’t good. I’m working on this one). With my not-so-good habits, should I start making a routine?

  • SongYii

    Is it necessary to fast at the same time each day? Sometimes I eat in a 6 hour window that ends later in the day, sometimes an 8 hour window that ends earlier in the day. I always eat within an hour of finishing a workout. Am I losing anything doing it this way?

  • iChido

    I’m planning on starting IF next week. I usually drink a pre-workout drink of half a school of NO-Explode. Would it be okay to still use the pre-workout on an empty stomach? Anyone out there with any experience with pre-workout drinks while on IF?

  • archaictext

    I think the comparison to cavemen in an attempt to support weight loss is logically unsound. A caveman (or his physiology) would not be concerned with weight loss. He would want to store as much as possible, considering he wouldn’t know when he would get his next meal, and there could be much time in between meals. So to follow a “caveman” style diet seems counter intuitive for weight loss. If you are making the argument that we may be better adapted to the “caveman” style of food consumption, that would seem reasonable, especially for glycogen storage and strength. But for getting the best looking body (as most people strive for in “weight loss” methods currently) this doesn’t seem to make sense. Also, people don’t live and work like cavemen did, so their bodies may require different methods of fueling. After all, you said people adapted to eating breakfast and several meals throughout the day, as it was difficult to “retrain” the body to consume by way of the “fast and feast” method. Other methods have worked very well for other people too.

  • Snoop

    Yeah, but calorie in equals calorie out is so untrue. I cannot believe people still arguing this. Research after research and science have proven time and time again that this simply is 100% wrong.

  • Snoop

    You don’t need carbs but your gut flora needs carbs. Check out “resistant starch” and why it is necessary for your microbes in your colon. Cold potatoes and rice has a good amount of resistant starch.

  • mikemarkham

    Humans don’t need carbohydrate, period. Gut flora is perfectly fine without it. I have read up on resistant starch. It is the new “magic” “superfood”. Plenty of cultures didn’t have access too roots and rice and thrived.

  • Alvaro A. Rojas

    I have been Testing this this Since August 31st until today, eating one 4 hr window a day, this are the resutls in numbers:

    Im 5´9´´, 26 years old, Male.

    starting weigth : 191pounds -Current weigth: 180 pounds
    Starting Bicep : 15.9 inches – Current Bicep: 15.5 pounds
    Starting Waist: 36.8 inches – Current Waist: 34.4 inches (around belly button)

    as you can see not much “muscle-loss” ;)

    I have been also training in a progressive way and saw very decent strength gains ( for example i could do 4 pull-ups ina row, now i can do 17! after almost 2 months)

    only whole foods and trying to eat those foods low carb in rest days, but still even if they are not perfect meals they are only 1.

    My workouts consist in dumbell work + HIIT +Heavy bag muay thai drills as at the time i have no access to a gym yet.

    only supplements: 1000mg vitamin c + Fish oil + Multivitamin.

    liquids during fasting : Coffe, Tea, water and sometimes a glass of wine.

    its been hard but not miserable, also i enyoi eating a feast when i do, and i can say when you adapt is much easier.

    in fact I leveled up today planning to include a 48 hr fast at the beginning of the week ( my last meal was sunday afternoon and next will be today afternoon) and keep the 4hr window the rest of the week.

    basically I wanted to share this works for me even though everybody thinks im starving when i tell them how much time i have been doing it they even say dont believe it or say i should be eating when noone is seeing me jajaja!!

    Hope Steve Reads this to see what he thinks as well :D

  • Alvaro A. Rojas

    nope you are fine, the
    window that you have is more than enougth to keep it smooth because you will
    actually spend more hours per day NOT eating than eating. (A 2:1 ratio of
    fasted versus fed.)

  • Alvaro A. Rojas

    Have a Glass of wine rigth before you eat, then swich to high (healthy) fat/medium protein/low carb and see what happens ;)

  • Elaine

    I would just like to add that the difference in men and women is obvious in my household. My husband is just fine with eating a small late lunch and a larger dinner. This baffles me but I’m alright with my weight. Remember women have a lot going on, balance is key, but I agree with some of these individuals to try it. Experiment with IF slowly. You’re not going to destroy your awesome system by IF for a month. Also insulin and glucose are besties. They need each other. If you shake when you haven’t had something quite sugary, don’t push the 24 hr time. That is all.

  • Emm

    Humans do need carbs. They are our main source of fuel. But I do agree that consuming natural carbs, such as fruit, veg & beans, are much healthier than refined sugars and processed grains.

  • Kelsey

    I love this idea, and I’m actually choosing to only eat between 2-4 PM. I’m really not a huge veggie eater, but I need something healthy that I can eat as much as I need to without it being an issue.

  • mikemarkham

    Factually incorrect. Look up gluconeogenesis. Dietary carbohydrates are not required by humans. Good thing, as you and I would not be here otherwise.

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  • Anurag

    I fast from 9:00 pm to 8 am and 1:30 pm to 8:30 pm will this work ?

  • Erika R.

    My daily schedule changes throughout the week, so I’ve approached IF like this: I wake up and begin eating like normal, so my 8-hour feeding window simply begins whenever I break the fast. So, this also means that my training occurs shortly after the feeding window is over, or somewhere in between. I’ll have an empty stomach, but may not be as “fasted” as others who are able to workout after sleeping. At any rate, this is my third day of IF and so far so good! I like that I’m not going to bed full and don’t have to worry about food for most of the day.

  • Ash

    I discovered Intermittent Fasting on my own, before I ever knew about the term or anything at all about it. It was completely by accident. It began when I started a busy job and only had time to eat one meal a day, just before I slept. Before I went to work, I had no time for breakfast, during work, I was too tired and used my lunch break to take a nap instead of eating, and when I came home, I just used the PC. I didn’t exercise at all and my job as sedentary work. Yet I lost 20 kilos in just 5 months, and almost all of my excess fat, but still kept most of my muscle mass. Now, years later, after finding out about Intermittent Fasting, I realize now that what I unknowingly did before was in fact Intermittent Fasting!

  • coolcats

    i work permanent night shift 6 on 2 off 10.30pm till 7am my systym is used to it as ive been doing this shift for 7 years however i have put on an average of 2 kilos every year since due to static type job and bad eating habbits what would this systym do for me? should i try it and reverse day for night , however I do have low blood sugars not bad but a hot chocolate fixes that

  • Ash

    Eat 1-2 to 2/3 of your daily required calories in one meal and fast for 24 hours. I require 2000 kcal and I eat 1000 of it in one meal at 8PM and don’t eat again until the next day at the same time (24 hr fast). I do this for 5 days a week (weekdays), and then eat 2 meals a day (total 1500 calories) within 6 hours at 12pm and 6pm on weekends and lost another 5 kilos in 4 weeks (in addition to my routine I mentioned in the other post below) without any form of exercise, doing a sedentary deskbound job.

  • shell

    Great article! I lost weight IF style, then decided to off load the last 12lbs in the supposed traditional way and over the last 6 months of counting cals managed to gain 12lbs instead, experimental for me to see which approach really worked. Started IF again beginning of this week and already 2lbs down so sorry to all the diet clubs out there but for me your plans did not work so i am sticking with IF, also am a diabetic and have greater blood work when IF followed!

  • disqus_pIGbqYXpum

    Hi.Thanks for your article.
    I’m a 17 years old boy.Does Intermittent fasting help me grow taller?
    It was my first day IFing and didn’t feel so much hungry at all.from 9:15 PM to 3:00 PM.When I got back from school.