12 Lessons Learned from 1 Year of Intermittent Fasting

Earlier this week, I posted a brief guide on getting started with intermittent fasting. You can read it here.

Intermittent fasting is a great tool for getting strong and lean without changing your diet. But it can also seem confusing or extreme if you’re not familiar with it. In fact, my guide seemed to prompt quite a few questions, many of which I responded to over email.

Because you may be wondering many of the same things, I figured I should write about them here as well as share some of the important lessons I’ve learned from practicing intermittent fasting for over one year.

Note: you can get even more ideas for living a healthy life (both mentally and physically), by joining my free newsletter here.

12 Lessons Learned from 1 Year of Intermittent Fasting

1. The biggest barrier is your own mind.

Implementing this diet is pretty simple, you just don’t eat when you wake up. Then you eat and lunch and go about your day. At least, that’s how I do it.

But there is a mental barrier to get over. “If I don’t eat will I not be able to think? Will I faint? Will I feel sick? What will it be like?” These are all thoughts that went through my mind before I started.

What ended up happening? Nothing. Life went on just fine.

Thinking you need to eat every 3 hours or six meals a day or always have breakfast or whatever it is that you’re convinced you have to do to survive … is all mental. You believe it because you were told it, not because you actually tried it.

If there’s one thing I’ve noticed that separates successful people from unsuccessful ones in life it’s not just the ability to think differently, but the ability to act differently as well.

2. Losing weight is easy.

When you eat less frequently you tend to eat less overall. As a result, most people who try intermittent fasting end up cutting weight. You might plan big meals, but consistently eating them is difficult in practice.

For this reason, I think intermittent fasting is a great option for people who are looking to lose weight because it offers a simple way to cut down on the total number of calories you eat without changing your diet. Even if you tell people that they can eat two large meals at lunch and dinner, they typically end up eating fewer calories than they would at 3 or 4 normal meals.

Most people lose weight while intermittent fasting because when they cut out meals, they don’t make up for it with bigger meal sizes.

3. Building muscle is quite possible (if that’s what you want).

I have managed to gain weight while intermittent fasting (I’ve added about 12 pounds of lean body mass and cut 5 pounds of fat over the last year), but only because I have focused on eating a lot during my feeding period.

As I mentioned above, the natural tendency is to lose weight on intermittent fasting because it’s easy to eat less when you cut a meal out of your day. However, at the end of the day eating 2,000 calories is eating 2,000 calories whether it comes during a 16–hour span or an 8–hour span. It just takes more effort to make sure you eat it all within 8 hours.

It’s totally reasonable to build muscle as long as you eat enough.

4. My best work is usually done when I’m deep into my fast.

I’m most productive during the first 3 hours of my morning, which is about 12 to 15 hours into my daily fast. This is the exact opposite of what I expected when I started out. I assumed that if I didn’t eat for hours, then I wouldn’t have any energy to think. The reality is just the opposite.

I have a lot of mental clarity in the morning when I fast. I can’t say for certain if this is due to the fasting or the fact that I’m just refreshed when I wake up, but one thing is clear: fasting is not hindering my ability to get things done in the morning. In fact, I’m almost always more productive in the morning when I’m fasted than in the afternoon when I’m fed.

5. For best results, cycle what you eat.

Intermittent fasting works, but I didn’t start cutting fat at a significant rate until I added in calorie cycling and carb cycling to my diet. Here’s how it works…

I cycle calories by eating a lot on the days that I workout and less on the days that I rest. This means I have a calorie surplus on the days I train and a calorie deficit on the days that I rest. The idea behind this is that you can build muscle on the days you train and burn fat on the days you rest. And by the end of the week, you should have done both.

Additionally, I cycle carbs by eating a lot of carbohydrates on the days that I train and few carbohydrates on the days that I rest. This is done to stimulate fat loss. I eat high protein all the time and moderate to low fat on most days. Cycling carbohydrates has also led to additional fat loss.

For me, this is when the intermittent fasting seemed to pay off the most — when I coupled it with calorie cycling and carb cycling.

6. Like most things, you should take a long–term view of eating.

Too often we think about our diet in super short timeframes.

It’s better to think about what we eat over the course of a week than over the course of a day (or worse, a few hours). For example, whether or not you have a protein shake within 30 minutes of working out, is largely a non–issue if you’re getting a meal of quality protein within 24 hours of working out.

One reason intermittent fasting works is because the super short timeframes that we are pitched by food companies and supplement companies are largely a myth. Let’s say you eat 3 quality meals per day. That’s 21 meals per week. Over the course of a week, do you think your body cares if the meals are eaten from 8am to 8pm (the normal eating schedule) or 1pm to 8pm (an intermittent fasting schedule)?

How about if we stretch it out over the course of a month? Wouldn’t it make sense that if you ate 80 quality meals every month (about 3 per day) that your body would make the most of those meals whether you ate them in an 8–hour block or a 12–hour block on each individual day?

When you take a slightly longer view, you start to realize that the time difference between eating from 8am to 8pm versus eating from 1pm to 8pm isn’t that large over the course of a week or a month.

7. It’s strange, but when I’m fasting I want food less.

Now that I’ve started fasting, I want food less. I’m not addicted to it. I’m not a victim to my diet. I eat when I want because I want to, not because my body tells me I have to.

This is a marked change from my previous eating schedule and I think the additional power and flexibility I have over my diet now is a benefit.

8. Losing fat and gaining muscle can both be done, just not together.

If you’re looking to lose fat and build muscle mass, then the combination of intermittent fasting, calorie cycling, and carb cycling that I have mentioned here is one of the best solutions you’ll find.

You see, it’s basically impossible to gain muscle and lose fat at the same time. To lose weight, you need to burn more calories than you take in. You need to have a net calorie deficit.

To build muscle, you need to eat more calories than you burn. You need to have a net calorie surplus.

It should be fairly obvious that you can’t have a net surplus and a net deficit at the same time. For example, you can either eat more than 2,000 calories or you can eat less than 2,000 calories … but you can’t do both at the same time. This is why it’s basically impossible to lose fat and gain muscle at the same time.

However, if we get away from the small timeframes and start thinking about our diet over the course of a week or a month, then we start to have more options. For example, let’s say that you workout 3 days per week. You could organize your eating routine to have a calorie surplus on the days you train (i.e. gain muscle) and then a calorie deficit on the days you rest (i.e. lose fat). That way, by the end of the week, it’s possible for you to have spent 3 days gaining muscle and 4 days losing fat.

9. When fasting, I have made more gains by training less.

I’ve recently began testing a new hypothesis for strength training, which I call “Do The Most Important Thing First.”

It’s as simple as it sounds. I pick one goal for the workout and do the most important exercise first. Everything else is secondary. For example, right now I’m working out Monday, Wednesday, and Friday. I do two sessions each day. Upper body in the morning. Lower body in the evening. But I’m only doing one exercise each time (pushups in the morning) and squat or deadlift in the evening. If I feel like it, I’ll finish my evening workout with kettlebell work or bodyweight stuff (handstands, front levers, and so on).

The results have been very good. I’ve seen improvement each and every week over the last three months. It’s worked so well that I’m starting to think that it has very little to do with fasting, but instead is just a better way of training. I’ll write more about this in the future, but I wanted to note it here because when I compare it to the previous way I trained while fasting (snatch and clean and jerk three days per week, plus squat or deadlift), I seem to be making more progress.

10. As long as you stay under 50 calories, you’ll remain in the fasted state.

A lot of people like to start their day with a cup of coffee or a glass of orange juice. Maybe you’re one of them. I have a glass of water. Well you don’t have to dump your morning routine if you want to give fasting a try.

The general rule of thumb is that if you stay under 50 calories, then you’ll remain in the fasted state. I’m not sure where this number came from, but I’ve seen it dished around by enough reputable people that I’m going to go with it for now. Following the opinion of the majority is typically a lazy move, but in this case I think you’ll be alright if you want to have a cup of coffee in the morning.

11. Prepare to drink a lot of water.

I drank a lot of water before I began intermittent fasting, but now I drink an incredible amount. I’m usually over 8 glasses for the day by the time I get done with lunch.

You mileage may vary, but even if you don’t drink as much water as I do, I recommend having it at the ready.

12. The best diet for you is the one that works for you.

Everyone wants to be handed the ultimate diet plan. We all want the answers on one sheet of paper. “Here. Just do this and you’ll be set.”

This is why diet books sell so well. A lot of people are willing to pay for a quick fix, a diet in a box, or the nutritional solution to long life.

Here’s my problem with marketers telling everyone that their diet is the best: it’s like telling the whole world to wear medium sized shirts and then wondering why they don’t fit a lot of people.

In most ways, your body is the same as everyone else’s. But in some very important ways, it’s also different than everyone else’s. To find the diet that works best for you, you need to experiment and see what your body responds to.

This is why I enjoy intermittent fasting. You can play with your eating schedule very easily. Choose one that fits your lifestyle and that your body responds to. Once you figure out when you should be eating, then you can move on to the harder part: what you should be eating.

As always, your mileage will vary, but the most important thing is that you’re covering ground and moving forward.

51 Comments

  1. I have been doing IF for almost a year as well.. though I do two 24h fasting periods per week, and this has work good for me (lost some 10% body mass (95% of it fat) in 3 months though combined with a kettlebell revolution 3 month program, but I would be really interested to hear a bit more about your point number 9,

    for exercise you only do 1 exercise in morning and maybe 2 in the evening?

    The Kettlebell Revolution program was great and it worked, though lazyness, life (two small children, too much work) led me to stop.. but this statement in you number 9 has given me hope..

    do you think it would yield any result if i would do something like:

    3, times a week.
    for example:
    Monday Morning: Push ups, 3 sets, take it to the limit, and each week doing more push ups (even if its only one more) then the week before
    Monday Night: Squats, 3 sets, with our without kettlebell, and possible some kettlebell swings if time.

    Wednesday Morning: Chin-ups 3 sets, take it to the limit, and each week doing more pull-ups (even if its only one more) then the week before
    Wednesday Night: Lunges 3 sets, with our without kettlebell, and possible some kettlebell stuff,

    Friday morning: some triceps excerises maybe combined with some shoulder work
    Friday night: deadlifts and some kettlebell, probably swings

    you are doing something similar to this? for me this is very tempting, because its very fast when done, like 5-7 minutes per session,wouldn’t require full on shower etc since its so fast you dont really have time to break serious sweat.. (except maybe if you do serious kettlebell swings for like 4-5 minutes)

    • Martin — thanks for sharing. It’s cool to hear about people trying different lifting routines.

      Here are my thoughts on the workout scheme you mentioned.

      1. I would move the deadlifts to Wednesday and squat on Monday and Friday.

      2. I would do 5 sets of 5 reps for squats. Example: Let’s say you can do 5×5 with 100 kg. Work up to 100 kilos, then do 5 sets of 5 reps at your top weight. I usually rest about 3 minutes between sets.

      3. Pushups and chinups are great, but I wouldn’t go to failure. (I’m actually doing a program right now where I’m working towards 100 consecutive pushups. I’ll write an article on this whole thing when I’m done, but for now my main tip is this: work hard, but always leave a rep in the tank.)

      Even with the rest between sets, you can get the pushup/chinup sessions done in under 20 minutes and the squat/deadlift sessions done in about 30 minutes. Feel free to add the kettlebells on after if you wish.

      Overall, I think this program would get you solid results in a short amount of time if you focus and do each exercise well. That said, the most important thing is to actually do the program. Get your workouts in each day. You can modify the sets, reps, and rest periods as you go on to get it to work for you and your lifestyle.

      Good luck and thanks for reading. If you have any questions, just ask. I’m happy to help however I can.

  2. Hi James. Just came across your work etc via Abel James podcast, great listen. Been doing IF for about a year and the main benefit for me is mental clarity and diet adherence. Subscribed to the blog.

    Saying hello from Edinburgh, Scotland

    • Kurtis — welcome to our community! It’s great to have you here, especially since you’re from Scotland. I lived in Edinburgh for a little while, so you’ve got a fellow Caledonian over here.

      I’m glad you enjoyed the podcast and it’s great to hear about your success with IF. Feel free to share your progress, ideas, or suggestions in the comments anytime. Our community is always benefiting from the ideas of people like yourself who are putting methods into practice.

      And in the meantime, I’ll do my best to continue sending the good stuff your way.

  3. Hello James: Just heard your interview on Fat Burning Man and enjoyed it very much. I have been IF for 6 months and have been gaining muscle and getting lean. It is possible to gain both muscle and burn fat at the same time because of the HGH and testosterone throughout the day?

    Looking forward to more articles from you!
    Thanks Jack

    • Jack — thanks for saying hello. And I’m glad you found the interview useful. I really enjoyed giving it.

      As for burning fat and gaining muscle at the same time, I think it comes down to what you define as the “same time.” The processes for burning fat (calorie deficit) and gaining muscle (calorie surplus) are fundamentally opposite, so I’m doubtful that you can do both simultaneously. That said, you most certainly can do one on Monday and the other on Tuesday and so on. By the end of the week, you’ll have both gained muscle and lost fat.

      Regardless, I wouldn’t get too hung up on whether you’re doing both at the same time. For the most part, that’s just a marketing play that fitness companies want to push. The important thing is that you’re continuing to make progress and slow growth, and it sounds like IF is doing exactly that for you. Keep up the good work.

      p.s. Welcome to our community! It’s great to have another person who is focused on action and puts ideas into practice. Feel free to share your ideas anytime. I’m sure our community will benefit from your experiences.

  4. James: Thanks for the response! Great answer! Looking forward to hearing about your 100 straight push up challenge.

    take care,
    Jack

  5. Hi James,

    I am loving these posts on IF. I feel like I do this naturally sometimes because I don’t enjoy eating dinner just because it is “dinner time.” My family and friends sometimes have a hard time understanding this. I try to eat when I’m hungry, not because it is “time to eat.” Anyway, question about working out- do you time your workouts with your eating window? I’d like to run in the morning, but my eating window wouldn’t start until a little later in the day so I could accomodate having dinner with my family. I’m worried I will feel very hungry if I don’t eat right after running. Thoughts?

    • Kelly — good question.

      The short answer is that you can workout when you want if you get good nutrition within the 24 hours after working out. So if you’re continuing to fast for a few hours, it shouldn’t be much of an issue provided you’re eating good meals later in the day.

      That said, I typically try to have a meal post–workout. This could mean working out in mid–morning (at the end of my fast) and then eating “lunch” afterwards. Or it could mean working out in the early evening and then eating “dinner” afterwards. That’s usually how the timing works for me.

      If you would prefer to run in the morning, then that’s fine. You can try having a protein shake before or after. Otherwise, I would just make sure that you drink enough water. Make sure you stay hydrated while fasting.

      Hope that helps!

      p.s. Overall, I would be careful with the “only eat when I’m hungry” idea. It sounds reasonable at first, but what happens is that when you’re busy it’s easy to convince yourself that you’re not hungry. The result is that you have no normal eating pattern. I don’t think there’s anything wrong with fasting, but I prefer to stick to an eating schedule. Otherwise, you can find yourself not getting a steady stream of nutrition. I’m not sure if this applies to you, but I figured I would offer it up anyway.

  6. Thanks for all the great information. I’m on day 4 of my IF fasting journey. The first two days were easy, but I spent the 3rd day at home and it was tougher. I’m a triathlete and do most of my training at 5:30am, and I’ve still been able to fast from 7pm-11or12 the next day. Some days I do the bcaa drink to be sure I repair my muscles. I don’t do heavy lifting so I think I’m ok fasting after a workout. What do you think? I’ve lost 45lbs since 2011, but trying to lose the last 10-15 and get to 185 and 9% body fat. I’m hoping IF does the trick. Thanks again.

    • Bradley — first, thanks for reading and being part of our community here. It’s great to have you sharing your experiences.

      As for training fasted, my primary suggestion would be to keep track of how you feel and base your decisions off of that. Everyone will respond differently, but it sounds like you’re doing a good job of keeping tabs on your energy and how your body is reacting. In general, however, I would say that you’re fine training fasted.

      On a related note: I like to think of nutrition in slightly longer time frames that what you typically read about. For example, I think the nutrition you get on a daily or weekly basis is more critical than making sure you’re eating at exactly the right time. In other words, fasting in the morning will typically present no problems as long as you have eaten well the day or week beforehand. In my experience, the nutrition you get in the 24 to 48 hours leading up to your workout is more important than what you eat an hour or two before or after.

      All of that to say: keep doing what you’re doing. Good work!

  7. James!

    I wanted to thank you both for writing such a fantastic, motivating blog and for introducing me to IF. I am enjoying watching my weight go down by basically doing something that involves no effort – skipping breakfast! I was hoping you could elaborate more on your exercise routine or even better write up a post for newbie exercisers that want to get into the game but don’t have the experience, perhaps incorporating a little more info on Carb/Calorie cycling (or am I asking for two posts!). I have waded through the Leangains site, and the other links in the other article you wrote on IF and while very interesting is WAY too complex for me at this stage.

    Regardless of whether you have the time/inclination to take me up on my request, please keep up the GREAT writing, I have been sharing with all of my friends/family. Thank You!

    Paul

    • Paul — it’s so awesome to hear that you’re making positive changes with the information I’m putting out. Thanks so much for reading and for being part of our community here.

      Also, both of your suggestions are on my writing list. Stay tuned and keep up the great work!

  8. As you say, the diet thing is confusing. What we all really want is for medium sized shirt to fit everyone, but as you rightfully say, it just ain’t so.

    I’m an experimenter when it comes to health matters. Been lifting weights fairly consistently for 40 years and have tried many different diets and cleanses. And even for me it’s tough to be consistent enough and flexible enough to try a different eating routine long enough to determine what best works. So, I imagine for the person not so experimental it’s near impossible to truly know what size shirt fits.

    I’m contemplating writing up a guide that offers different diet protocols based on a persons entrenched habits. So the breakfast skipper can try the intermittent fasting, and the big breakfast eater can make sure (s)he gets 30 grams of protein and fiber for satiety. The carb addict will learn about choosing complex carbs. The fat addict about avocados and omega 3 oils. That sorta thing.

    Anyway, keep at it, James — like your work.

    Yep.

    -Joe

    • Thanks Joe! It’s always great to hear your take on things.

      I think the most important thing is something you mentioned right away: to be an experimenter. Nothing works for everyone, but with a little work you can find out what works for you.

  9. Hi! I loved this post as I am starting out IF myself and so far I have found I have the most energy I’ve had in years and it started from day one. It’s amazing because I’ve always felt sluggish and no matter what I tried, nothing worked. Anyway, I have a question. I do my fasts everyday (7 days) with a 6-8 hour window depending on the day. I love breakfast and I’m not too fussed on dinner so I usually have my window between 8:30 to 10:30am to about 2:30 to 4:30pm. Is that okay to do? I’m trying carb cycling too and I normally workout in the morning right before I finish my fast, then I have breakfast. I do strength training 3 days (Mon/Wed/Fri) and a body combat class every Saturday morning. It might be a dumb question but I haven’t seen anyone doing those hours sort of earlier in the day, everyone does it after 12pm and it’s just not for me. Thanks!

    • Ally — thanks for reading! It’s great to have you in our little community.

      I’m glad to hear that intermittent fasting has worked well for you so far. As for your question, the timing doesn’t make much of a difference. If you want to eat breakfast and lunch, then that’s totally cool.

      Keep up the good work!

  10. Hi James,

    A very clear article and very lucid. Thank you.

    I am a 61 year old male with adrenal fatigue issues and low testosterone/excess estrogen issues. I fell for the idea that I must eat every 2-3 hours and have been obsessed about eating all the time. This is promoted heavily for people with weak adrenals.

    I just started 3 days ago and skipped breakfast but actually have the toast and eggs at 4 pm, so I am doing three meals anyway in the 8 hour period. I think this will reduce as we go along. I really like the 16/8 schedule that you are following.

    I still feel very lethargic in the mornings in spite of the fast but hoping this will reduce as the body finishes cleansing with this fast.

    I am not able to do any high intensity training due to my fatigue issues, hopefully this will change.

    Thank you for all your info.

    Kailash

    • Kailash — I’m happy to help and I certainly hope that you see progress with whatever regimen you end up following for the long-term. That said, I want to be clear that my articles should not replace medical advice given to you by your doctor. There are many reasons for this, one of which is that your situation and circumstances are unique.

      I’m not saying that you shouldn’t try fasting, but I am saying that an article I write (for the general population) and advice given to you by your doctor (specifically for you) should not be treated as interchangeable options.

      With all of that said, I want to reassure you that I will always do my best to provide the most useful information possible. And thank you for reading. I really appreciate you being part of our little community!

  11. Hello James, I have 7lbs to lose and I’m very interested in the 16:8 and the whole intermittent fasting, I have been doing the 5:2 for the past month successfully as I have lost 14lb, which is good. The question I have, James, is when you have a fast day, how many calories can you have, is that a restriction of 500-600 calories as in the 5:2? Thank you for your clear and concise explanations of the 16:8.

    • Heather-mae — I fast every day with the 16/8 split, so I don’t limit my calories in anyway. (I’m also not looking to lose weight.) I simply eat as much as I want during my 8-hour feeding period. Obviously, the most important thing is eating clean, healthy, unprocessed foods.

      Hope that helps! And good luck!

  12. I’ve been doing IF for over a year now, and I agree with all of this. My best work by far is in the morning when I haven’t eaten for 12+ hours, and I frequently lose that clarity of thought and focus as soon as I start eating. Combining this with a diet of carb-cycling has been extremely effective in letting me lose weight when I want to cut, and also gain weight when I want to get stronger. Thank you for spreading the word!

  13. I’ve been fasting for a little over 1 yr, and have combined HIIT and strngth training. The one point with this article where I have a substnatial difference of opinio is the statement that it is impossible to eat to build muscle and lose weight at the same time. My understanding (as a layman) is that muscle isn’t built from carbohydrates and calories, but from protein, amino acids and minerals. Therefore there is no inconsistency in a diet that is high in muscle builidng nutrients and low in calories. I think that the other thing I would always emphasis is that workouts don’t build muscle, rather muscle is broken down during the workout and then re-built during rest periods. There fore its better to excercise in fasted state rather than “load” with calories etc., but after excercise, in the resting state, eat nutritionally dense foods.

  14. Hi, I just started IF a few weeks ago and thank you for sharing your experience.

    Just a quick question. I’m a 20 year old female and I have been counting calories for about a year now. After experimenting with different daily intakes, I’ve settled on 1400 calories a day. I’ve decided to do IF to break the plateau I’ve hit because I haven’t been losing weight any more. If I do IF, can I still consume 1400 and lose weight or should I restrict more calories?

  15. Sorry I have the following doubt, maybe you can help me.

    I usually fast and I run marthons too.

    My problem is that I usually train between 7:30pm and 9pm because I have to work during the day. So after training I do only meal of the day and then go to bed. Since the meal is very close to bed time I dont get to sleep well.

    I choose this schedule in order to train fast and get the proteins after training. But this screw my sleeping. I will like to re-schedule my feeding time, but I don’t know which hours are better. I am thing of breakfast or lunch time.

    Please tell me what do you think?

  16. Skip breakfast?

    Hi James,great article!..thanks for the information. Here is my situation, I only do weight training and I stated taking jack 3d (pre workout) recently..love it working great for me, as it allows me to fully complete all my reps and sets but after workout I don’t feel like eating nothing not even in next 2/3 hours, except water.I get so dried up that feel I can drink the whole ocean. Its mostly because of the pre work out probably, besides I drinks tons of water anyway. I work out in the morning on Mon-Wed-Fri days and by the time i finish it is almost 10, I don’t feel like having breakfast at all after and I can easily wait until noon for lunch.

    My question is can I safely skip breakfast after training which would allow me to practice IF, in another words how much valid the concept is that you should eat right after weight training to repair muscle? I also read somewhere we should wait like an hour after workout to eat cause the testosterone/other fluids body secrets from workout will be cancelled by the sugar/insulin we’ll get from food if we eat right after. Is that true? I really wanna practice IF but not sure about the whole muscle repair thing right after workout. I will take breakfast the every other days I wont workout that would also comply with calorie surplus and calorie deficit concept as you mentioned but the opposite way for me. You mentioned to eat more on work out days and eat less on non-workout days but like I said I don’t feel like having breakfast on workout days, so I will cut breakfast and eat less on workout days.

    I am not a huge muscular guy, have a moderate body with some definitions but with some fat in my lower abs and slight love handles. Do you think if I practice IF and skip breakfast, that will help me get rid of those fats? My goal is to grow muscle and get rid of fasts from those regions to get a better cut.

    Thanks in advance. Much appreciated.

  17. Great article thought I wonder why you treat yourself so gingerly during IF. IF is not real fasting. I’ve been doing the warrior diet for over two years and have also water fasted for over 30 days in a row. With IF you’re still getting all the calories you need, you’re just allowing your body to empty itself completely between meals. All this “Too much exercise” is overrated. I’ve done crossfit during IF, now I follow a 6 day per week routine of hundreds of push-ups, pull-ups, squats, sit-ups as well as 3 days of distance running and 3 days of the Insanity videos each week. No problem. You have to watch out for yourself when you do real fasts but not during IF. You can do whatever the hell you want. There is no science behind “eating every 3 hours”. It’s all mental. I do agree that the “fasted state is the most productive.” You hit that one spot on. Keep up the good work.

  18. I have been doing IF since a few weeks now. I kept my usual paleo diet and skept breakfast. My goal is weight loss, but instead I’ve gained it. Any advice?

    • Weight is dependent on calories. Check what your BMR is, multiplied by your activity level, and how many calories you’re eating. As long as you’re ~ 15-20% below, you will be losing weight. If you’re GAINING weight, then you’re either weighing yourself at inconsistent times, or you’re not eating 15-20% below your maintenance calories. One or the other.

  19. I have recently gotten an interest in IF. I’m on Day 3, and I’m doing pretty good. Before IF, in the last 5 months, I’ve lost 90 lb, and my weight loss continues as it always has, because I still eat at a calorie deficit. But IF these last few days help me manage my hunger and cravings – and my body is surprisingly good at adapting to only eating once a day.

    Anyways, my comment is regarding “not being able to build muscle while losing weight”. I have run this across my mentor (coworker who got me started on weight loss), who debunks it with “Your body is burning your fat for energy. It can just as well burn some more to build some muscle”.

    Meaning, as long as you work with your muscles, they will adapt to what you do, and if they need to strengthen up, then they will grab from your fat stores to help up.

    But I could just be misunderstanding what you write. Because I equal losing weight to losing fat. But if you mean that you can’t lose weight while gaining muscle, because you are putting on more muscle weight, but still can lose fat weight, then I think we both agree.

    But what I’m trying to get across here is my mentors argument: It doesn’t matter where the energy comes from (food or fat) – if its there, the body will use it.

  20. Hi James,

    Thanks for your articles I love each and every one of them.

    I read in one of your article re IF you said that for women is better to fast 14 hours instead of 16. Can you please kindly explain the theory behind it?

    Thanks a lot.

  21. Hi James,

    I’ve been doing the IF thing for just a week now. The first day was the hardest.

    Regarding your 16/8 split… I have to say, it just kind of sounds like skipping breakfast! I always thought breakfast was over-rated.

    But thanks for this info. Very helpful.

  22. What about fasting every other day for the entire day and working out on your eat days and chill in your fast days?

  23. Hello James!
    In point #5 of your post you mention:
    Additionally, I cycle carbs by eating a lot of carbohydrates on the days that I train and few carbohydrates on the days that I rest.

    That makes totally sense, since low calories and low carbs for 12-72 hours allegedly lead to fat burning without messing up the metabolism.
    Assuming one trains at night (e.g. having an office job discourages morning workouts), how should the Carb Cycling be implemented for optimal fat loss?
    a. Consume high carbs in the time frame before (i.e breakfast and lunch) and after the workout?
    b. Consume high carbs only after the workout?

    Thank you in advance!

  24. I am doing Sagi Kalev’s the Body Beast workout, which is quite tough! How will I manage it with IF?

  25. Everybody keeps reiterating the fact that you are supposed to drink a lot of water on an IF regimen, but I have yet to hear the “why.” Can somebody explain? I, frankly, find it pointless to force-drink myself into spending half the day in the bathroom if the only benefit is to “stay hydrated.”

    • Firstly, it keeps you full. Secondly, it helps recover, fat metabolism, boosts immune system, and just about every other good thing for you. Your body and your muscles are mostly water.

  26. Great article!

    Quick q: do you ever switch up times when you fast? My schedule changes on weekends (primarily Sunday) and times when I hit the gym (40 mins heavy weightlifting + 10 mins HIIT/10 mins low intensity cardio) change.

  27. Hi James,

    I’m doing IF as well, and it’s indeed a very nice way of living.

    I just would like to know: how many kcal a day would you eat on a training day? And how many on a rest day?

    Greetings,
    Steve

    • Probably 10% above maintenance on workout days, 20% below maintenance on rest days. Calculate maintenance based on your BMR multiplied by activity level. Do that and you’ll gain strength and burn fat.

  28. Hi James,

    Your lessons all ring true. I started IF last September doing 2 x 24hour fasts per week and shed 1 stone and was delighted with the results. I stopped doing it once I reached my goal but since have put weight back on by eating out of character… so started IF again this week. I have lost 2lbs already and as you say… it’s mind over matter all the way.

    thanks

    Wendy from Fife :-D

  29. Hi James,

    First off, I want to say that I have thoroughly enjoyed reading your journey through IF and training. I’m a graduate of Cell & Molecular Biology/Chemistry and as such am very interested in different eating styles and time frames and the effect on metabolic state.

    For myself, I have always struggled with obtaining the “ideal” body image. I say “ideal” in quotes because I am using the world with respect to what I believe MY ideal image should and can be. Recently, since summer of 2013, I began doing the 5:2 diet by Dr. Michael Mosley and actually did achieve a fair amount of weight loss. However, I do feel that the “weight” loss was very much muscle based as opposed to fat. I have been reading up on Alternate Day Fasting (or ADF) and have read a book called The Every Other Day Diet by PhD Krista Varaday. The science is there and she has conducted numerous studies with large population sizes (mainly on the effects of ADF on weight loss in obese individuals) but I honestly find it extremely difficult to limit myself to 500 calories (her recommendation for women) every other day. I have also found that this is made ever more difficult since I began weight training in the mornings before work. By the time 1hr post-work out rolls around, I am starving. This method of alternate fasting (AF) has also caused me to gain weight instead of lose as I feel myself bingeing on the “feast” days.

    So, after all this and after reading your personal experience (and the experiences of many others), I have decided that the 16hr fast-8hr feed of IF would be a good method of fat loss for me. One thing I wanted clarification on from you was with respect to calorie and carb cycling. I am familiar (albeit not fluent) in cycling but was wondering if you cycle on the same days that you follow the 16hr-8hr rule? As in, on weight training days, would you still eat within the 8 hour period but simply eat more calories and/or carbs, and then follow this by a non-weight training 8hr feed day that focuses on less calories/carbs?

    Phew. Sorry for the novel! I hope this is clear!

    Thanks so much and I look forward to hearing back from you,
    Kate

  30. Hi James.

    I’m kinda new to trying out IF. This is my 6th day. I will go right to my Q for you. Yesterday I weighed 92.2 kilos 16 hours in to my daily fast, I had a meal after 21 hours. A good solid meal with high protein and less of carbs and fat.

    Now I’m on my 15 hour again. But i have gained 2 kilos? How can that be? I drink a lot of water while fasting. I have Googled a lot on the subject, water and fasting and gaining weight of just having water during fast but I fall short of finding a good answer. Hope you can provide me with one.

    Thanks.

    Krille, Sweden.

    • It could just be water weight. If you’re eating below your maintenance calories, you will lose weight – period.

      If you want to see how significant water weight is, try this. Weigh yourself now, fully hydrated. Then don’t drink anything for a few hours (go to the bathroom as usual). Then do your usual 40 minute cardio session, grab a shower, pat yourself dry. You’ll probably lose 2-3 lbs just like that. Weight is a terrible measure of body fat – if you want to lose body fat (the answer is ‘yes’, btw), then you need to eat below your maintenance calories.

  31. I’ve been doing the surplus on 3 lift days a week, deficit on 4 rest days. I’ve remained exactly the same weight for 3 months, though I’m stronger now. How did you gain weight??

  32. This is a very helpful article. I am starting this diet today. :)

    Thank you for the information.

  33. I am looking to start IF however i am an early bird and i love to do my strength training in the morning. Won’t this plan effect my current routine? Is it really ok to do strength training while being about 9hrs fasted?

  34. Hello, I found this very interesting as I am trying to look more lean and shredded and I have 10-15 lbs to go! I was wondering though, I am doing the Stronglifts 5×5 and I was wondering if it would be unwise to fast for 24 hours on weight train days and eat on non weight train days? Thanks so much for this page. I plan on fasting every second day if that’s smart or should I do it only twice a week?

    • Stronglifts is a good program, but if you’re going to fast for 24 hours, I would switch your strategy. Eat on the days you workout and fast on your rest days. That said, I don’t think it’s necessary to fast 24 hours, multiple times per week. One 24-hour period per week, should be plenty.

  35. I have a question on calories/carbs cycling. Does meal time matter?

    I’m an office worker and I work from 8-6pm and train in the evenings. I get the impression that you should eat and replenish nutrition AFTER a workout (it makes sense too since you deplete energy and “damage” muscles during the workout).

    So on my training days if I do a high calories/carbs diet, should I time them to eat the largest meal around my workout time?

  36. I thought that muscle was broken down on training days and built on resting days. If on the resting days you don’t have enough calories how would your body build muscle? This does not make sense to me.