Fasted Weight Training: The Definitive Guide

Fasted Weight Training

If you’ve been in the weight and strength training game a while, you’re bound to have heard about intermittent fasting, training on an empty stomach and all that.

And you probably thought that sounds like a terrible idea.

We mean, maybe a light Pilates class can do just fine on an empty stomach, but intense exercise? NO WAY.

And yet, people continue to train while fasting, so you got a bit curious – why are they doing this? And might there be some perks I can benefit from here? 

In this ultimate guide to fasted weight training, you’ll discover everything you need to know about this type of training and how it benefits your overall health and helps you achieve your fitness goals.

What exactly does it mean to be in a ‘fasted’ state?

Because many of us, when we hear about this kind of training, immediately jump to images of a big effort and not eating for days on end.

Anyway, fasted weight training is not like that at all.

See, after we eat something, our body begins to digest it and slowly turns it into energy (often referred to as fuel by trainers and websites).

During this digestion process, the body breaks down your food into tiny molecules then, it transports them to the bloodstream.

This process supplies your bloodstream with essential nutrients and the production of insulin increases in order to transport those nutrients around the body. 

This is why some people can faint or feel ill if they haven’t eaten in a while because they’re missing those essential nutrients and their insulin levels have dropped down to a minimum, which isn’t ideal.

Now, the period in which this digestive process is taking place is referred to as the ‘fed’ state and can last anywhere from 3 to 6 hours, depending on your metabolism. 

The ‘fasted’ state refers to the period immediately before or after the ‘fed’ state.

Once the body has finished processing the food, its hormone levels drop, and glucose and insulin in the bloodstream automatically go down.

In other words, the body doesn’t have any more nutrients to distribute and your body is running on empty.

Beware though that feeling a bit peckish does not automatically mean you’ve reached this fasted state.

You may be approaching the end of the digestion process, but not be quite there. 

Many people know this rule of thumb that you should wait at least an hour or two after eating before you train.

While this makes sense, because it allows the body to partly digest that food and lowers the risk of vomiting it all up, you’re still in a fed state.

So as we’ve seen, you don’t need to go without food for insanely long periods of time, but rather a few hours. 

what are the benefits of fasted weight training?


It might sound silly. Of course you’ll feel weaker when you’re in a fasted state, so why would you want to undergo vigorous training then? Wouldn’t it make more sense to do it a safe while after you’ve had a healthy meal?

Actually, there are quite a few reasons why you should train in a fasted state.

You see, when your body grows low on insulin (as it does in fasting), it will turn to your fat reserves as a primary source of fuel.

Normally, it would use glucose (which you get from food rich in carbohydrates), but since you’re in a fasted state, that means you’ve just run out of insulin, and need to turn to the next best thing: fat.

And, this is exactly what many bodybuilders want – to put on muscles and just burn through that fat storage.

Here are the top 5 benefits of fasted weight training.

  • Fasted weight training burns Body fat Quickly

This is thanks to a process known as lipolysis and fat oxidation.

Studies have shown that weight training while in a fasted state allows you to increase these processes, which in turn allows you to burn through that fat faster.

One study actually found that you can burn 20% more fat if you train on an empty stomach then you would if training after your meal.

This is because your body has other resources to use once you’ve eaten and doesn’t need to lay into that fat storage quite so heavily. 

  • Fasted Weight Training Increases Muscle Growth

And isn’t that, after all, why we’re here?

Contrary to what many people seem to think, muscles don’t actually grow while you’re working out, but afterward.

See, when you’re lifting weights or performing any type of physical exercise, you’re creating these small tears in your muscles

And once you’re done training, your body starts repairing those tears by sewing them back together, as it were.

This process is known as protein synthesis and in order to sew your muscles back together, your body is basically creating new muscle fibers called myofibrils.

Well, studies have shown that training on an empty stomach increases the rate at which your body repairs.

That is because when you eat after your workout, your body will have a better anabolic response to the nutrients.

Having a better anabolic response meaning that you’ll rebuild your muscles faster, which is excellent news for you!

  • Fasted Weight Training Increases Insulin Sensitivity

What exactly is insulin sensitivity, we hear you ask?

We mentioned earlier that when you eat something, your body requires insulin in order to carry essential nutrients into the bloodstream and through the body. 

The only problem is that as we continuously eat more than we actually need, our body grows less and less impressed by insulin and slowly develops a resistance to it.

This is dangerous because it does not allow insulin to do its job and prevents important nutrients from reaching their destination.

Which is where fasted weight training comes in.

As we saw, this type of training is closely related to insulin, more exactly to training on a limited insulin supply.

By doing this regularly, your body becomes accustomed to working with less insulin and grows to appreciate it more when it’s around, to put it simply. 

By forcing it to work more on a limited supply of insulin, your body becomes more sensitive to insulin levels.

It’s like when you have a huge feast before you, you don’t really care or appreciate it as much as you should, but when you only have a few scraps, it becomes that much more important to you.

By becoming sensitive to insulin, your body ensures that these essential nutrients get to where they need to be, and thus keeps you healthy.

  • Fasted Weight Training Increase Blood Flow to Your Abdomen

More specifically, to your lower abdominal region, which is one of the hardest areas to lose weight in, as anyone who’s ever tried will tell you. 

You may have noticed that even though the rest of your body is fairly toned, you still continue to spot some extra weight in the lower abdomen.

Well, once again, this is an area in which fasted weight training can help. 

Certain studies have shown that working out on an empty stomach improves the blood flow in that area, which in turn makes it easier for you to lose weight. 

  • Weight Training on an Empty Stomach Improves the Way You Use Oxygen

Obviously, the way in which you use oxygen during a workout is essential. 

The better your body is at using it, the better the output will be, and fasted weight training can actually help you with that.

Why? Because it increases VO2 max, which essentially refers to how your body uses oxygen.

By improving that, also allows you to burn more fat, which once again, is why we are here. 

Some studies show that weight training without eating can also increase your power and allow you to do more in the gym. 

So overall, there are loads of reasons why you should want to train on an empty stomach, but you no doubt still have lots of questions about it.

So in this ultimate guide to fasted weight training, we’ve taken it upon ourselves to answer those questions for you.

Is fasted weight training safe? 

Unfortunately, the simple fact that it has a hoard of great health benefits does not actually make it safe for you to practice.

To put it simply, yes, training on an empty stomach is safe from a medical point of view.

As we’ve seen, we’re not talking about a week in the desert kind of fasting, but rather going without a meal for a little while longer, which is okay in the long run.

As long as you are not starving yourself or eating very little, you should be okay to perform just about any type of exercise on an empty stomach.

Your body doesn’t give up that easily!

Should you get into fasted weight training?

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Now that’s a bit of a different question, and in order to answer it completely, we need to look at a few aspects.

First, we need to look at the way you are training and what kind of exercises you are performing.

We’ve talked about weight training quite heavily in this article, and while we know that fasted training can be immensely beneficial, there are also some downsides. 

For example, you might not be able to perform as well or as fast on an empty stomach.

This depends heavily on how long you plan on training as well.

If you’re only doing something like 20 minutes of exercise before you shower and eat and go about the rest of your day, then you shouldn’t experience any issues.

If, however, you plan on training for more than that, like an hour, then your body might not respond so well.

Another huge aspect that you need to pay attention to is when you are training.

It’s beneficial to perform fasted weight training in the morning, right after you wake up.

First of all, that’s because you are sure to be in a fasted state by then, as all food would have been digested during the night.

You are also more energetic in the morning and have a better chance of achieving peak performance.

Studies have shown that leaving several hours (even without eating) go by between your wake up time and the time you train decreases your ability to perform. 

One final aspect you need to be aware of is what your main purpose in this training is:

Are you preparing for a competition?

If so, then fasted weight training should be a good idea.

Are you trying to lose weight?

Then maybe you should eat something before you hit the weights, as fasted weight training will actually make you hungrier.

And if you end up eating more after the workout, that will pretty much negate all the benefits we saw above. 

So, Should you train on an empty stomach

From what we’ve seen before, the answer really depends on the individual, but we urge you to consider these aspects before making a decision.

We’d also like to remind you that fasted weight training over a long period of time increases the risk of muscle degradation, as your body pulls at essential amino acids in order to preserve the glucose levels and overall healthy functioning of the body.

There are numerous arguments to be made in favor of fasted weight training, as we’ve seen.

But, there are also some arguments to be made against.

Remember, you want to get the best you can out of your training!

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1 thought on “Fasted Weight Training: The Definitive Guide”

  1. Julie A.

    This is really helpful for hopefully losing a little bit more weight before bikini season. I’d heard about Fasted weight training before but never really had a guide like this to help me out. Hopefully I can get some work outs done!

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