Mini Mikkipedia - Fasted vs Fed Training: What the Research Really Says
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Hey everyone, it's Mikki here. You're listening to Mini Mikkipedia on a Monday. And today I want to revisit just briefly a topic of conversation which is never very far from social media or questions that I get from clients and members of my group, particularly as we head into, you know, when I'm dealing with a whole group of people, many of whom train early in the morning. And that is the topic of fasted versus fed training. Now this has come up
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again this week because of a recent publication back in May in the International Journal of Sports Nutrition and Exercise Metabolism. And it's talking about whether or not you should train in a fasted or fed state and what difference this makes to adaptations to resistance training. So now this was a study conducted over 12 weeks, looking specifically, as I said, on resistance training. And it was on a group
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of 37 participants, 22 of whom were females, and they trained either fasted and then had breakfast, or they trained after breakfast and then went about with their day. This particular group looked at muscle thickness, muscle strength, and changes in fat mass and fat-free mass. And essentially what they found was regardless of whether or not they trained on an empty stomach,
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or between one and two hours after consumption of a carbohydrate-rich breakfast meal, there was no difference in muscle hypertrophy, in strength and neuromuscular changes, in fat mass and fat-free mass. And in fact, potentially, there was an increase in fat-free mass in the group that trained fasted. And so with this particular study, what we might suggest is that it doesn't really matter
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If you eat before after resistance training, you're going to get the same gains. And the potential pitfalls of training fasted, which people always talk about, which include compromises in muscle mass, fat loss, in your strength or your power production, these are not or were not seen in this particular study, which is super interesting. And
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I guess what I would say is that if you look at this one study alone, you could absolutely conclude it's not going to make a difference whether or not you train fasted or fed. However, of course, for every one study that shows that it's potentially fine, benign, innocuous, no difference, you are going to find another study to show something different. And I remember hearing Abby Ryan Smith on a couple of different podcasts. She's awesome. I haven't yet talked to her, would quite like to. And a study out of her lab that was
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not dissimilar to this study and it was conducted however over half the time period, it was six weeks. They did it in females exclusively, albeit young females. mean, these were young adults too, this one that I was just telling you about. And they also trained twice a week doing what was called a high intensity resistance training program. They looked at leg press or they, I'm sorry, they did leg press, bench press, shoulder press, bicep curls and
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tricep extensions and I think lunges, dumbbell lunges. So quite a good program, know, quite all round. And in Abby Smith Ryan's study, there were three groups actually. One got something, got a shake that had 25 grams of protein and 16 grams of carbohydrate before exercise. One group got that same shake after exercise and there was another smaller control group that did not get any nutrition. And they wanted to compare
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differences in fat oxidation, resting energy expenditure, and strength related outcomes. What this particular study found was that there was no difference in strength when they looked at leg press, but there was a significant improvement in bench press when you were looking at those females that had either pre or post workout nutrition. There was no real difference in resting energy expenditure,
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though those group that had something before exercise, there was a lower RER, so increased fat oxidation post exercise when it was measured at 30 minutes. So someone could look at that study and go, well, there is a benefit actually from having some nutrition around training. And particularly if you have it before training, you might get an increased fat oxidation post training.
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So you can see why people get a little confused as to, you know, what is going to be best for me to do with how I train and how I eat. And of course, you know, there are many limitations to, or there are always limitations, I'm sorry, to both to any study. Some could say that the first study I mentioned, the most recent one by Vieira and colleagues is that, well, they were young adults. They weren't all female. They only trained twice a week.
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and how good was their diet related information that was collected anyway? Whereas with Abby Smith Ryan's lab, you could also say, well, they were young, exclusively female, but still young, with an average age of 20 and a half. They too only trained twice a week. And while they did collect diet information, it was on a subsample of individuals and it wasn't a big study anyway. I will say exercise science never has really big studies because
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It's a super expensive thing to do to conduct human trials. whilst it's a critique, it's not like a criticism of that particular study or any study. Any study could potentially inform the space or the questions that we're trying to answer. And then as a practitioner, I just have to also put my hat on as well because when we're at and trying to inform our clients of best practices and best evidence for whether or not to train, fasted or fed,
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It really comes down to three different avenues of evidence, if you like. And of course, literature and science is one of them. And so you've got mechanistic trials that look at what happens at the molecular level with nutrients on board or not, whether or not that actually translates into human clinical trials. And then also, what does observation tell us? If we look at a group of individuals and they always train fasted, are they
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you are they more likely to lose muscle mass or not across, you know, several years? And so if we can use all lines of evidence, what does the evidence actually tell us? And then of course, you've got the client in front of you. And so you've got your clinical experience and you've got your personal experience. What do you know about, you know, how do you feel with FASTED or FEB training? And personally, me, I have gone through several years during my thirties, late twenties,
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not really eating almost at all before I went training. And also, I was over training at the time and under fueling in general. And I don't think that was a particularly great model to, or example. So I don't think my personal experience in that space can really inform what other people should do. But I do think about that when I'm thinking about the person in front of me and what their overall goals are for sure. And a few major take homes if you like for me from this is
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that it's all very well and good if someone is training just twice a week. But what if you're training a little bit more than that? Will that actually change any of these outcomes? I do think about that a bit. know, like very few people probably only train twice a week and are more likely to have a routine where they get up and they're out the door. If they're training in the morning, they may be doing it four or five times a week. So that's something. And then I think age is a really important factor actually. So if you are 20 and you're training fast at all, you're training fed.
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You might actually also have time to go home and have, you know, if you go train faster, you might have time to go home and feed up after that training session and head out the door to your, you know, the classes that you've clearly got on because you're a very convenient sample for a particular study. So you're going to be used in these types of studies, which is again, totally fine. But I mean, that's the reality of it, right? Like college aged students don't necessarily reflect women in their forties or men in their forties. And so.
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Think about two different scenarios, right? Because I did see another post on social media that Stu Phillips put out, is absolutely true, is that you can go to a 6 a.m. CrossFit class fasted and have breakfast at eight and be completely fine. And you're not gonna have to worry about appetite, worry about muscle protein synthesis or any of these other potential pitfalls of training fasted. And if that is you, and if you do fall into the camp of four or five times a week, you do fasted training,
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at 6am, you go home, shower, grab your breakfast out the door at your desk at 8 o'clock eating breakfast and then you have your lunch at 12 o'clock and it's a decent lunch because you bought Saskia and I's 40 over 40 book. You've also put in a piece of fruit alongside that just for a little bit of added carbs or you've chosen a loaded athlete bowl. Then mid-afternoon you have another snack because
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hey, you're hungry and you did have a pretty decent workout that morning and you actually do need to eat more than three times a day for the most part. So you've got some yogurt and protein powder and berries or a protein shake or a piece of fruit and a hard boiled egg or something like that that will tide you over to dinner. And dinner might be at about 6.30 and then you're having a cup of tea and a piece of chocolate and you're cooling it down by about eight o'clock. So if that is you,
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and your sleep is great and your recovery is awesome and you continue to make gains and you feel amazing and you feel good and all biomarkers would also suggest that there's not an issue, then it really isn't an issue. However, consider another scenario where you get up to train fasted at six o'clock, you come home, you shower, you don't bother with breakfast because you know there'll be morning tea at work and you rush out the door, you grab a coffee, might be a latte, might be long black.
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You arrive at work, you clear your inbox, you go to your first meeting at nine o'clock, 10 o'clock is the morning tea, but you don't really have anything there. You have a couple of bites of something, but a lot of it is stuff you would probably think, oh, I'm not sure I should eat that. Does it really align with my goals? You get through to 11.30, might have a handful of nuts. You have lunch at one o'clock. It's the same lunch because you too bought our cookbook, 40 over 40 lunch book. But then at three o'clock, that hunger kicks in. Not only hunger, but the fatigue.
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you have a bit of brain fog and you find yourself grazing as soon as you get in the door, you have dinner at 6.30 again and then you can't stop eating or you continue to graze. You're not quite satisfied till you go to bed at about that same 8.30, nine o'clock and you feel exhausted. You don't recover well and you're not quite sure what's gone wrong because in your mind you get through the morning on no food. So you should be okay. And I think in this instance,
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It actually isn't about the faster training itself, albeit do that six days a week and it's not that great. But I think really what this can do is set someone up for a mindset of faster training and of under eating. And I used to do this all of the time. So if you can sort of get up and go faster with no food and then just have a tiny bit of food to get you through to lunch, then you're sort of like in your mind, you've got this mindset of less calories.
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benefits of fasting, improved fat loss and things like that, which actually doesn't set you up for a great day, does it? Not the way that I described it. And instead, if you had it in your mind, I'm gonna have something before I exercise, because I know I feel better when I fuel, or let me try fueling this workout. And you get up and you have something before the workout, and then you go about your day and you have that breakfast, lunch and dinner, maybe you're actually gonna feel a whole lot better. And so I just wonder what mindset
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people sort of get into when they're on that faster training bandwagon. And particularly when they're running a calorie deficit or they're wanting to improve their body composition. Because there is less calories going in anyway, you need to make sure that the calories that are going in are helping support that workout. And this is of course particularly important when we think about things like low energy availability across the morning. You we know that it's not even about low energy availability across a day, but even in that
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early morning or the hours of the morning window, if you don't have enough calories going in, it can be detrimental to bone and it can be disruptive to hormones. We've got studies showing that too. So what mindset does fasted training sort of set you up with? And that I think is where my practitioner hack comes on because I of course train fasted now and fueled. So I look at my workouts and I, well, I do one of two things. It depends on if I'm hungry when I get up or not.
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and maybe I'm hungry two days out of seven, but often that aligns with my longer training runs as well. So I'm going to fuel that. And I mean, I don't have a ton. I have like a protein bar, might be about 220 calories or something like that. So it's not a full on meal, but it's enough just to sort of give me some fuel in the tank. The other thing I would say around training fed versus fasted, and this is just a practical tip, is that if you know you can't stomach anything in the morning, not even water, then
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make sure your dinner the night before is really good. So ensure good calorie intake. You've got some potato, rice, sweet potato, or something like that in your dinner. might even have something post-dinner, like a protein snack. Not that you necessarily need it, but it might just help with the calories in general. So you haven't just had like a miserly dinner before going to bed and getting up to train again. So really to me, like I don't know that these studies necessarily are not like...
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definitive in terms of whether training fasted or fed is better or worse. So how do you train fasted and how does that set you up for the other things that you do across a day? Because you know yourself whether you should be doing a bit more or are you under doing it and your biofeedback should be able to tell you that. What is your sleep doing? What is your energy doing? What about that brain fog? What about your hunger? Are you able to manage it? Are you feeling satisfied and
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Do you have good satiation after your meals? And what's your recovery like around training and post training? And are you able to hit that workout again the next day? Like these are all important questions to ask yourself. So don't just go by what social media tells you is what you should or shouldn't be doing. You really need to check in with yourself because that's ultimately going to give you a much better answer than what gurus on social media will. Anyway, I'd love to hear what you do.
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So hit me up in the DMs. I'm at threadsxandinstagram @mikkiwilliden, Facebook @mikkiwillidenNutrition, or jump on over to my website mikkiwilliden.com and go all the way down to the bottom and put your email address in for an email from me, because you can jump on my newsletter and then you'll find out all of my ramblings every week, lucky you. All right, team, you had the best week. Thanks.