Intermittent Fasting for Muscle Growth (Full Plan)

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Can intermittent fasting be as effective as a more traditional 4 or 5 meal a day diet plan for building muscle?

I mean, even though intermittent fasting has been shown to be effective for fat loss, there are many people still wondering if you can actually use it to build muscle as well.

While there is a small subset of individuals that do believe that you can in fact build muscle mass while fasting,

most coaches continue to hold the stance that it’s a bad idea. Some of them even claim that intermittent fasting will almost definitely lead to muscle loss.

However, many of their opinions are formed by outdated myths. For example, the idea that your body will start breaking down protein

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and amino acids for energy while fasting is what gave rise to the idea that fasting will cause muscle loss.

But this has been thoroughly debunked. When looking at what happens to a person that experiences starvation we see that before beginning the fast their body is breaking down mostly carbohydrates for energy.

It’s also breaking down some fats and a little bit of protein. (1)

Then after the fast begins, you see that the body drains the remaining glycogen or carbohydrate stores within the first day or two,

while increasing the use of fat and ketone bodies for energy. But the really interesting thing is that contrary to the myth of muscle loss accelerating while fasting we see protein breakdown rates decreasing from the norm helping the body conserve muscle instead. (1)

Another human starvation study found very similar results. During the first 3 days of fasting, protein breakdown rates dropped to only 75 grams per day for an adult man weighing about 150lbs.

That’s less than 1/2 a gram of protein per pound of bodyweight but what’s even more surprising is that after 3 to 4 days of not eating,

protein breakdown drops to a tiny 20 grams per day. (2)

This means that when you fast your body will significantly decrease its requirements of carbs for energy and instead of breaking down muscle, it will mostly rely on stored body fat for energy.

Even though certain organs like your brain will require glucose to function properly your body will be able to separate triglycerides that come from fat stores into glycerol and free fatty acids.

While the free fatty acids can be used immediately for energy the glycerol can be sent to the liver where it can be converted into glucose through a process known as gluconeogenesis ultimately keeping your blood sugar stable.

So the bottom line is, no you won’t be burning muscle every time you fast especially with relatively short fasting lengths less than 24 hours long.

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But the question remains can we BUILD muscle with an intermittent fasting plan?

Well even though protein breakdown rates don’t drastically accelerate while we fast,

we don’t build muscle just by slowing muscle loss we also need to increase protein synthesis and keep it elevated to build more muscle.

The problem is that after you’ve already fasted for some time, protein synthesis rates are going to below.

But While muscle protein synthesis may be impaired during a fast, the good news is that fasting does provide a sort of amplified rebound effect when you do finally eat after your fast is over.

Research shows that after a fast, your body can stimulate muscle growth to a much greater extent than it would be able to if you never fasted at all, to begin with. (3)

Picture your body being like a sponge that slowly dries out as you fast, but then after you break your fast your body is able to absorb and assimilate more nutrients for the muscle-building process in the same way that a dry sponge is able to absorb more water.

So, your body makes up for the lack of protein synthesis and muscle growth during a fast with an increase in growth during your feeding window.

We can see this play out in one of the very few good randomized controlled trials that are available on the topic of intermittent fasting and its effect on muscle growth. In this study,

the researchers observed bodybuilders during the month of Ramadan. And they found that when the men maintained a similar calorie and macronutrient intake during Ramadan as they maintained before that period, they would see no adverse changes in body composition during the month of daytime fasting. (3.5)

In other words, based on that data, when fasting is done correctly it has either no or very minimal negative effects on muscle growth.

Now, some people go on to say that you can actually build more muscle with intermittent fasting because your growth hormone levels will rise. (4)

But even though your growth hormone levels will rise several-fold while fasting, this does not enhance muscle growth.

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That’s because the increase in growth hormone is not a net anabolic event and it won’t lead to a more beneficial protein turnover rate.

This is partially due to the fact that it comes at the cost of IGF1-production, which is a hormone that’s even more important for muscle growth than the human growth hormone is. (5)

In other words, when you fast, you produce more growth hormone but less IGF-1. That’s why your muscle protein turnover rate does not increase during a fast, even though you have higher human growth hormone levels. (5.1)

Instead, during a fast, your body will be in a negative whole-body protein balance. But that doesn’t mean that the higher levels of growth hormone are useless.

Instead of helping you build muscle, it functions as an anti-starvation response – Meaning the increase in growth hormone helps transition your body into burning more fat and ketones for fuel as we talked about earlier. (5.2)

The growth hormone assists the release of fat from fat cells and helps stimulate fat oxidation in general.

This helps spare glycogen and amino acids during a fast. Ultimately, the increase in growth hormone will not build up new muscle tissue; instead, it will prevent muscle loss while fasting.

So now that we know that intermittent fasting can help you build muscle in a similar way to other diet plans,

but it won’t help you build extra muscle due to growth hormones we just have to make sure that we set up our 8-hour feeding window for optimal muscle growth.

And the reason why I say an 8-hour feeding window is because if your goal is to build muscle I don’t recommend that you go for longer fasts like the warrior diet

and the one meal a day diet, and instead stick to a 16/8 split. This is because regardless of whether you’re eating 2 meals a day or 5 meals a day you’ll need to maintain a calorie surplus to build muscle. It’s difficult enough to eat enough protein, carbs, and fats, all within 8 hours,

so that’s why I don’t recommend that you shorten your feeding window any more than 8hours for the purpose of building muscle.

With that said, if you still can’t eat all the calories that you’re required to eat within an 8-hour window then you’d be better off not doing intermittent fasting and instead of eating more meals throughout the day to hit your surplus calorie targets.

Remember without a calorie surplus you’re probably not going to grow.

Out of all the macros the most important to make sure you’re having enough of is protein because you’ll want to maintain a positive nitrogen balance.

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This essentially means that the intake of protein and nitrogen into the body needs to be greater than the loss of protein or nitrogen from the body.

Some studies show that you should ideally spread your protein servings for the day into a minimum of 4 meals for maximum muscle growth.

(6) And that you should aim to have anywhere between 0.8 to 1 gram of protein per pound of body weight for the day.

While it shouldn’t be a problem to eat enough protein for the day, it most likely will be a problem to squeeze 4 meals into an 8-hour feeding window.

But the good news is that your body is very smart and adaptable. As long as you’re eating all of your protein and calories to meet your targets for the day, your body should be able to absorb all of the nutrients from larger meals even if they’re eaten less frequently.

Digestion of the larger meals will simply take more time, but the protein and other nutrients will still be absorbed.

This has been shown in a couple of studies, but one study in particular compared one group that was following a warrior diet where they fasted for 20 hours a day and only ate during a 4-hour feeding window to another group that followed more of a traditional approach with more meals throughout the day.

Since the warrior diet group had to eat all their protein for the day within 4 hours they were eating anywhere between 80 to 100 grams of protein pretty much in one sitting.

By the end of the study, researchers found that both groups maintained the same amount of muscle mass,

and they concluded that intermittent fasting does not affect the breakdown and absorption of protein, carbs, and fats. (7)

So the bottom line is that you can still absorb enough protein and nutrients to build muscle with less frequent larger meals, but to be safe and for optimal results,

you may want to also spread your protein intake between your meals evenly regardless of how many meals you’re having per day since there are other studies out there that show that having a more balanced distribution of protein between your meals can help stimulate protein synthesis to a greater extent. (8)

Now to set up your own intermittent fasting plan for muscle growth that’s based on your body you can click the link in the description for the fat loss calculator and follow the steps.

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Just remember to select “hard gainer” as the last option since that will give you the right amount of calories for building muscle.

After you have your results you’ll want to do your best to spread those calories and macros out evenly between 2 to 4 meals per day all within an 8-hour feeding window.

Then you would fast for 16 hours where you wouldn’t eat or drink anything that contains any calories, and repeat.

It’s essential to note, though, is that you should be consistent with your fasting and feeding schedule.

So, don’t fast for eighteen hours today, twelve hours tomorrow; and then switch back to a regular eating style the day after that.

Such an irregular eating style hurts health and fitness in many ways including lowering the thermic effect of foods, decreasing insulin sensitivity, impairing cardiovascular health, and disrupting your circadian rhythm. (9)

So choose your fasting schedule and stick to the same one consistently. This doesn’t mean that you have to obsess about breaking your fast an hour early or starting your fast an hour late, but you shouldn’t be jumping all over the place. (9.1)

Now the last thing that you’ll want to remember is that for your muscles to grow you need to also be training correctly regardless of what diet plan you’re on.

While the most important dietary stimulus for muscle growth is to maintain a calorie surplus and to consume enough protein, (9.2)

the number one “training stimulus for muscle growth is progressively overloading your workouts.

To progressively overload your workouts you can add more weight to your exercises over time.

While this may sound simple, it gets harder and harder as you increase the weight load you’re using more and more.

Undulating periodization can be particularly useful to help you break past plateaus where you’re stuck using a certain amount of weight.

With undulating periodization, you would be switching up your rep range for every one of your workouts.

I recommend switching between a higher rep range of 10 to 14 reps, a moderate rep range of 6 to 8 reps, and a low rep range of 3 to 4 reps.

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You would make sure to lift the heaviest weight that you can barely squeeze out for the given amount of reps for the day, and cycle your reps for every workout.

So on your first chest day, you might aim for 12 reps, on the second chest day you would aim for 6 to 8, and on the third 3 to 4 reps. Then repeat.

Keep in mind this is just one example there are many ways to set this up, but by cycling like this your muscles will get better a pushing through fatigue and clearing out lactic acids with the higher rep ranges,

and you’ll also get the benefits of lifting really heavyweight and increasing strength and power with the lower rep ranges.

Ultimately this helps you progressively overload your workouts even if you currently feel stuck.

In regard to when you should be training, if you should be training fasted or if you should be training in a fed state, it’s entirely up to you.

If you feel low on energy whenever you train fasted you may be better off working out after you break your fast and have your first meal.

On the other hand, if it doesn’t bother you to train fasted the only thing I would recommend is to try to have a protein shake or a meal soon after your workout.

Not only will it slow protein breakdown rates, but it’ll also get amino acids into your bloodstream and drive up protein synthesis rates.

Also like I said earlier fasting before your workout and then taking a protein shake with some carbs afterward can help stimulate more muscle growth after a heavyweight training workout (3).

So that about wraps it ups guys, just remember as long as you’re progressively overloading your workouts, eating enough calories and enough protein, there’s no reason why you can’t build muscle with intermittent fasting.

If you guys enjoyed this video and feel like you’ve learned something new make sure you subscribe to my channel and hit that bell icon so you can be notified whenever I release new free tips and tricks just like the ones you found in this video.

Also if you’re looking for a done for you intermittent fasting plan for muscle growth based on where you’re at right now,

visit my website where we have 6, 12, and even 16-week challenges designed to help you build muscle while staying lean.

All of our programs come with workout plans that contain full video demonstrations. You’ll also get a diet plan designed to help pack on muscle mass, a recipe book, and an accountability coach to help guide you through the whole process.

To learn more you can click the link in the description below, or you can visit my website directly at gravity

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My passion for fitness began when I was 14 years old. I naturally fell in love with training and haven’t stopped since. At 18 years I acquired my first personal training certification from ACE after which I opened my first of 3 transformation studios in 2011. I love to share my knowledge through personal training, my online courses, and youtube channel now with over 3,000,000 subscribers! I can happily say that we've helped over 15,000 people get in great shape over the years. I'm always here for my customers so if you need help don't hesitate to send your questions to

Founder // Gravity Transformation, Max Posternak