Bodybuilding is a wonderful sport. Gaining slabs of powerful muscle, then shredding down to reveal all your hard work- and it’s that last part that an intermittent fasting bodybuilding lifestyle will help tremendously with.

Intermittent fasting is the most powerful fat loss weapon I’ve used for the past four years, and it’s the main factor that’s allowed me to stay ~10% body fat year-round (while slowly building muscle).

Therefore, intermittent fasting and bodybuilding go hand-in-hand, especially when you’re looking to lean down. So lets take a look at the ins and outs of intermittent fasting for bodybuilders.

“But what about IF and muscle gain?”

It depends how you do it, but I would advise you to use intermittent fasting primarily for fat loss purposes. If you’re a beginner bodybuilder who purely wants to focus on mass gain, then you may need more meals and more spaced out protein.

But if you’re doing intermittent fasting for bodybuilding and your primary goal is fat loss, then this could be a life-changing style of eating for you.

Here’s what I recommend…

How Long Should I Fast?

This is the most common question bodybuilders have in regard to intermittent fasting. The answer is that it depends on the individual’s goals more than anything.

For example, it wouldn’t be the best idea (obviously) for someone to be doing a 36 hour fast if their goal was to pack on as much size as humanly possible within the next year.

There’s just not enough calories in there, your cortisol levels will be too high, and protein synthesis will be non-existent. This strategy might work for some guy who is obese though.

Similarly, it might not be the best route to hitting 8% body fat if you’re eating from 8 am – 12 am (and only fasting 8 hours while you sleep). You may need a wider fasting window and some appetite control mechanisms in there so that you get shredded with minimal hunger, stress, and fatigue.

Some other intermittent fasting protocols that may interest you:

Alternate Day Fasting

This can actually be pretty useful for a lean bulk, depending on how you do it. It’s one of the examples of where intermittent fasting and building muscle CAN go hand-in-hand.

The way I would suggest is doing a ‘normal’ day of eating for your training days to help you get the carbs, calories, and overall recovery in. Then on your days off, stick to your intermittent fasting plan (whether that be OMAD or 16/8 fasting – see below).

So on one day you’re fasting for 16 hours, on training days it’s only 8 hours (like normal).

This way you’ll definitely be maximizing your post-workout nutrition and performance on training days, but it’ll be hard to overdo the calorie surplus due to the fasting days when you’re not training.

OMAD (One Meal A Day)

This can make for an excellent bodybuilding cutting diet if you’ve gone over say, 16-18% body fat during your off-season bulk.

In this scenario, you may actually need to only eat one large meal per day, to really force your calorie intake down.

What I suggest to manage appetite following this model, is to have plenty of tea, coffee and maybe sparkling water as well throughout the day.

Another aspect to be aware of is the potential difficulty of getting enough protein. There’s an easy fix – have a large protein shake as ‘dessert’, immediately after your main meal. It’s still part of the OMAD meal but tops off your protein intake.

20/4 Fasting

This is literally 20 hours fasting, 4 hours eating.

Like with OMAD, it can make for a fantastic cutting diet, especially if you gained a little too hard/dirty in your off-season.

But the difference is that you’re getting two main protein servings spaced 4 hours apart, and your calories may not be quite as low.

Ultimately this will be better for muscle retention depending on various factors like how much body fat you gained while bulking, your current training and sleep, etc.

But what about if your body fat lies in the 10-15% range as it does for most bodybuilders?

What’s the best intermittent fasting approach?

Assuming your goal is fat loss, you’re probably going to want something like the following…

16/8 Fasting For Bodybuilding

This is the most popular version of IF, and it’s also the easiest to do.

It’s literally 16 hours fasting, 8 hours eating. Most people opt to have an eating window from 12 pm to 8 pm, although it can be any timeframe – the best one will be the one that suits your schedule.

It’s also the easiest thing in the world to start with.

All you do is push your breakfast back by two hours for the first week, and then after pushing it back by another two hours in the second week, you’re good to go.

Another really powerful fat burning trick I recommend is to drink black coffee in the morning when you’re fasted. It helps massively with keeping you satiated, while also boosting your metabolism.

So why exactly is 16/8 fasting good for bodybuilding specifically?

The main intermittent fasting benefits in my opinion, are:

• The appetite reduction you experience (you WANT to eat less food)
• The reduced insulin levels
• The flexibility of the overall system (no rules on macros or foods like there is with keto or paleo)
• You get greater protein synthesis levels with 16/8 than you would with OMAD or 20/4

All of this makes for a relatively easy and effortless journey to sub-10% body fat, which is where you want to be if you want to look your best as a bodybuilder.

Intermittent fasting is a powerful tool that will enable you to look more ripped, more striated, and more chiseled.

What Foods Should You Eat?

As I said there are no strict rules on your food choices or macros, but there are some general pointers I’d like to mention.

Obviously, if you’re eating junk food in your 8-hour window, not only are you going to struggle to lose fat over the long-term, but your health and energy levels are going to suck too.

You need good food choices on your intermittent fasting bodybuilding journey.

Breaking The Fast

Lots of people want to know how to break a fast properly. My advice, generally speaking, it’s a good idea to stay low carb when you’re breaking your fast (usually this is 12pm).

Going for a high carb meal simply spikes your relatively low insulin levels too high and too fast, leading to an energy crash.

Something like fish, eggs, some veggies, or some red meat would all be better ideas for breaking your fast, and making your bodybuilding cutting diet easier overall.

The Evening Feast

This is usually where I recommend guys get most of their carbs, as it’s not going to crash their energy levels. Even if they do feel a little tired afterward, it’s night time so it’s not as much of an issue.

Another benefit for a lot of guys is that this acts as a post-workout meal for them, and the carbs will go a long way to replenishing glycogen stores, improving sleep, and improving overall recovery levels.

So in addition to your chicken/turkey/steak/fish, feel free to have plenty of rice or potatoes. Of course, the quantities need to be tapered to your size, activity level, and fat loss goals, and this is where an intermittent fasting bodybuilding meal plan would come into play. But the above covers your basics.

And here’s a side point that nobody really talks about:

This evening feast is what allows your intermittent fasting bodybuilding journey to be sustainable – because it’s enjoyable.

There are too many guys out there who deprive themselves of their social lives or with their significant other, and this makes dieting painful, and that low body fat more difficult to maintain.

The evening feast changes all this, as you now get to consume ~70% of your daily calories in that one meal, whether you’re alone or with your friends/family.

What About Intermittent Fasting And Working Out?

The big question that I always get asked – can you workout while fasting?

The answer is – yes and no.

You absolutely can work out fasted at the beginning of a cut, especially if you’ve spent 6-12 months gaining weight and have tons of ‘stored energy’, higher blood sugar levels and sky-high energy to work with.

But I don’t think it’s ideal once you’ve been losing weight for more than a handful of weeks. Once you’ve been in a calorie deficit for 3+ weeks, and/or you’re below 12-14% body fat, you’re going to want carbs pre-workout if you want to maintain intensity throughout the entire session.

So my suggestion for bodybuilders for the majority of their cut:

Train during your eating window, rather than your fasting window.

For most people, this means later in the day, but you could also have your eating window from 8 am – 4 pm if you’re following 16/8 – it’s completely up to you.

Either way, get your pre-workout meal in so that you can train hard enough to maintain your hard-earned muscle.

What you could do is break your fast with the recommended foods above – things like salmon and eggs, and then a couple of hours later, 30 minutes before your training session, have a banana and some other faster-acting carbs to fuel your training. Post-workout could either be a protein shake, or your meal #2.

I’ve found this to be the best muscle-retention strategy while burning fat effectively with Intermittent Fasting.

Some other Intermittent Fasting Bodybuilding questions I get:

Does Creatine Break A Fast?

Here’s my hard and fast rule with regards to breaking a fast, and it’s something you can apply to just about anything else that you have questions about:

If it has calories in it, it breaks the fast. Zero exceptions.

Creatine doesn’t have any calories in it (assuming you’re getting pure mono), and is something I highly recommend for bodybuilders who care about their muscle mass (which is 110% of bodybuilders).

Definitely take your creatine every day – timing doesn’t appear to matter according to the studies.

Does Bulletproof Coffee Break A Fast?

Bulletproof coffee seems to be all the rage these days, but I’m not a fan.

It’s essentially just pouring oil into your coffee, which has calories and therefore does indeed break your fast.

My view is that these are fat calories that should be saved for when you’re cooking or meal prepping later in the day. Cooking proper meals like steak or fish or chicken with veggies.

Not for putting in your damn coffee.

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Can You Build Muscle While Fasting?

I briefly covered this above with alternate-day fasting, but I’ll expand a little.

Technically, the answer is yes, but it depends on various factors. The number one unbreakable law is that you’re going to need a calorie surplus (although drugs may well change this).

It also depends on your current starting point. If you’ve only built 3-5 pounds of muscle so far, you may well continue to gain a little size doing OMAD for example, for a while.

But what if you’ve gained 30+ pounds of extra muscle over your bodybuilding career?

You’re going to need that calorie surplus like a fire needs oxygen. A surplus is your muscle gaining lifeline, and realistically, you’re going to need ADF for this over the mid-to-long-term.

Plus the protein synthesis levels are just higher – you’re getting loads of protein servings throughout the day, which are required if you want to get huge.

But if fat loss is your primary goal, Intermittent Fasting could be the best thing you ever do.

Summary on Intermittent Fasting for Bodybuilders

Intermittent fasting is an eating system that makes fat loss both effortless and sustainable, and you should consider using it especially during your cutting phases, or if you’re trying to stay lean year-round.

Technically, you’re allowed to eat anything you like (similar to IIFYM), although I’ll be completely honest – some foods are simply superior to others, and you’re better off getting higher protein, low sugar meals if you want to optimize your fat loss results over the long-term.

If you want to know more about 16/ fasting, read my Intermittent Fasting 16/8 Diet guide.