Fasted Weight Training: Can You Build Muscle Lifting Fasted?

December 28, 2020
Nutrition, Training

lifting weights fasted


People turn to intermittent fasting as a dieting method for fat loss and it’s potential health benefits.

 

Fasted cardio is popular among those looking to shed those last few pounds of stubborn, unwanted body fat.

 

But what about fasted strength training? Can you still have great workouts and build muscle while lifting fasted?

 

Will it help with fat loss?

 

Should you do it?

 

Will you lose muscle?

 

All those questions, answered right here.

 

Table of Contents

 

Reasons For Fasting

You may be wondering why in the world someone would fast.

 

In other words, why would anybody intentionally not eat for over several hours.

 

Well, for one, you fast when sleep—assuming you sleep enough and don’t get up for a snack in the middle of the night.

 

Others do intermittent fasting, also known as time restricted feeding (TRF).

 

Certain religions will fast as part of a ritual or celebration. Ramadan is a perfect example. Ramadan lasts thirty days. During this time, Muslims will fast from sunrise to sunset.

 

If you’re unfamiliar with intermittent fasting, or time restricted feeding, it’s an eating pattern that involves cycling between periods of eating, and periods of fasting. The most common eating pattern is 16/8. This means you fast for 16 hours and have an 8-hour eating window. The 16-hour fast can include time you’re sleeping. 

 

Intermittent fasting is typically used to drop body fat. Since your eating window is restricted, you’ll likely consume less calories, and lose body fat. Intermittent fasting is often chosen because people find it very convenient and it fits nicely into their busy schedules.

 

Pros of Lifting Fasted

No food in your stomach while training

Many people don’t like training with any food in their stomach, and I don’t blame them. I much rather go into my workout a bit hungry than even slightly full from my previous meal.

 

This is one of the benefits of training fasted. Your previous meal from over several hours ago is fully digested. Your stomach is empty and you don’t run the risk of feeling uncomfortable, becoming nauseous, or experiencing digestive issues.

 

When you’re training in the gym, blood flow to working muscles increases. After you’ve eaten a meal, blood flow to your digestive system increases as it begins to break down and absorb the food you ate. If you eat too much too close to your workout, your muscles and digestive system could end up competing for available blood supply. Your muscles and digestive system won’t be competing for available blood supply if you lift on an empty stomach. You can maximize the amount of blood flow to the muscles being trained, without obstructing digestion. This could result in better workouts.

 

It can be convenient

Let’s say you work a 9 to 5 job. You don’t have the energy to lift after work in the evening, so you’d like to get your workout in before work. There’s a few problems though. You don’t want to wake up at 5 AM, eat your meal, let the food digest, then make your way to the gym. You’d have to wake up earlier than you’d like and it takes up more of your valuable time. 

 

You also don’t like eating a small snack before the gym. You sometimes eat a bit too much, it’s difficult to get the timing down just right, and you don’t like training with food in your stomach. It’s uncomfortable and negatively affects your workouts. 

 

This is where lifting fasted is useful.

 

You can save time, sleep more, and still have great workouts by fueling up the night before with a large meal. You don’t have to wake up, eat, and then wait around for your food to digest. 

 

Instead, you wake up, get hydrated, and hit the gym. The food from the night before is enough to fuel the workout and you avoid lifting with food in your stomach.

 

It could help you eat less calories throughout the day

Skipping your pre-training meal and heading straight to the gym in the morning could result in less calories consumed throughout the day.

 

If you skip that meal, your eating window is now smaller, assuming you also stop eating at the same time as usual. When your eating window shrinks, it’s likely you’ll end up eating less, and ultimately you’ll lose body fat.

 

If your goal is weight gain, this could be disadvantageous. You’ll have to eat larger meals throughout the day to make up for the skipped pre-training meal in the morning, but larger meals could be a great thing for those will bigger appetites. 

 

Larger and more satisfying meals 

Another benefit to lifting fasted is that you will be able to eat larger meals throughout the day. If you’re going without eating for longer periods of time, your eating window shrinks, which allows for larger meals to meet your caloric needs.

 

For those who don’t have much of an appetite, this may be a bad thing, but for the majority of you, this is a great thing. Larger meals are typically more satisfying and enjoyable than smaller ones. 

 

Cons of Lifting Fasted

Performance could decrease

One of the potential drawbacks of lifting fasted is a reduction in energy levels, strength, and endurance. Your performance and the quality of your workouts may not be up to par if you haven’t eaten in over several hours. 

 

We each have a different body and different preferences. For some people, no matter how much they eat before fasting, their workout still won’t be very good. Maybe it’s mental, all in their head. Or maybe it’s actually physiological, or a bit of both. Fasted training isn’t for everybody.

 

You could end up eating more throughout the day

I mentioned earlier how hitting the gym fasted could make you eat less since your eating window gets smaller. Well, for some people, it does the opposite. It’s not uncommon for people to overeat once they break a long fast. Not just for that one meal, but throughout the entire day. Think about a time when you went all day without eating, then finally got home or to a restaurant. Your appetite was probably through the roof, your cravings were stronger, and you probably ate quite a lot. Fasting could increase your appetite beyond what’s typical for you. You end up eating more than usual, and going over your calories for the day.

 

If your goal is fat loss, this could be an issue. If your goal is to pack on more muscle and become stronger, this could be a good thing.

 

You’ll have to experiment with yourself and see where your appetite stands and whether you can keep your calories in the range you’re aiming for. 

 

The potential for more protein breakdown, muscle damage, and further depleted glycogen stores

Pre-workout nutrition is important for limiting protein breakdown and muscle damage, increasing muscle protein synthesis, and filling your muscle glycogen stores. Fuel your body properly before training and you can initiate the recovery process quicker by providing your body with the nutrients it needs in advance.

 

By the time you complete your fasted workout, your last meal was about 12 hours ago. That is, if you’re training first thing in the morning after an overnight fast. If you’re intermittent fasting, your last meal may have been 16 hours ago or more. 

 

When it’s been that long since your last meal, muscle protein breakdown and the degree of muscle damage may be higher. Your muscle glycogen stores may be very low. For these reasons, it’s crucial to get your post-workout meal in as soon as possible. Aim for a 2:1 to 3:1 ratio of carbohydrates to protein, with at least 25 grams of protein.

 

Can You Still Build Muscle?

Yes, you can absolutely train fasted and build muscle.

 

As mentioned above, when training fasted your post-workout meal is extremely important. Get that meal in as soon as you can. 

 

If you don’t want to wait until you get home to eat, or you have a long commute to wherever you’re heading next after the gym, there are some meals that do not require refrigeration that you can take to the gym. This way you can eat immediately after your workout.

 

Whey protein is a great fast-absorbing, complete protein that can be mixed with water, oatmeal, or cream of rice. You can cook the oats in water at home, toss in a scoop or two of whey protein along with cinnamon and fruit. Store it in a Tupperware container and bring it to the gym. You can use those same ingredients to make a shake in the blender.

 

Bagels, rice cakes, bread, granola, cereal, maltodextrin, and dextrose are other great options immediately post-workout. 

 

Choose quality protein sources like chicken breast or thighs, lean red meat, ground turkey, ground beef, fish and other seafood, whole eggs, egg whites, cottage cheese, or Greek yogurt.

 

Then combine that with carbohydrates like potatoes, sweet potatoes, rice (white or brown), oats, quinoa, sprouted whole grain bread, whole wheat bread, whole wheat tortillas, rice cakes, sprouted grain breads, granola, sprouted grain and whole grain cereals, fruits, and vegetables. 

 

Make sure that at the end of the day you’re consuming enough calories, protein, carbohydrates, and fats. Whether you’re training fasted or not, your macronutrient and caloric intake for the entire day is matters most when it comes to body composition and performance. Skipping breakfast won’t ruin your progress, just like a proper pre and post-workout meal won’t make up for an overall lack of nutrients and energy. 

 

Will Fasted Lifting Speed Up Fat Loss?

No, it’s highly unlikely lifting will speed up fat loss.

 

In this study, researchers experimented with a group of bodybuilders to analyze the differences in body composition when resistance training in a fed state versus a fasted state.

 

Researchers conducted this study with sixteen Muslim bodybuilders during Ramadan. Eight of them trained fasted and eight of them trained in a fed state. The fast typically lasted fifteen hours.

 

By the end of the thirty day study, the group training fasted did not see any significant changes in body composition compared to the group that trained in a fed state. Both saw very similar outcomes.

 

Another study looked at twenty healthy females between the ages of 22 and 25. One group performed cardio on an empty stomach in the morning after and overnight fast. The other group performed cardio after consuming a 250 calorie shake consisting of 40 grams of carbohydrates, 20 grams of protein, and 0.5 grams of fat. 

 

Participants did a 5-minute warm, then exercised at 70% of their maximal heart rate for 50 minutes, followed by a 5-minute cool down. 

 

Cardio was done 3 days per week for 4 weeks. Both the fed and fasted group ate nearly the same exact amount of calories, protein, carbohydrates, and fats throughout the duration of the study.

 

The end result? Both groups had a reduction in body fat, but the fasted group did not lose any more fat than the fed group.

 

Now, this was aerobic exercise, and not strength training, but now I’ve presented you with two studies–one on strength training and one on cardiovascular training—that shows fasted training will not result in any additional fat loss compared to training in a fed state.

 

So, train fasted if you’d like, but don’t expect to see any additional fat loss compared to training after a meal. Primarily rely on your diet to lose body fat, cardio as a tool to aid in fat loss, and weight training to preserve or gain muscle mass and strength. 

 

Train fasted, either cardio or weight training, if it fits your schedule and is convenient, but I wouldn’t go out of my way to do either of the two fasted. 

 

Will I Lose Muscle Training Fasted?

Muscle loss is always a possibility when you’re eating in a calorie deficit in attempt to drop body fat—even if you’re not training fasted.

 

Even if you’re training fasted while in a calorie deficit, muscle loss shouldn’t be any greater than training in a fed state if you’re doing everything right—eating well, eating enough, training hard, but training smart, managing stress, and getting plenty of rest and recovery. 

 

Now, if you’re consistently putting yourself through long and strenuous workouts, aren’t eating and sleeping enough, neglecting post-workout nutrition, and placing loads of stress on your body and not recovering, then yes, muscle loss is definitely possible. 

 

Besides, strength training alone temporarily increases muscle protein synthesis and is a strong stimulus to your body. It’s a stimulus that gives your body a reason to hold onto the muscle you have.

 

Muscle loss is highly unlikely if you’re eating in a calorie surplus. Keep up with your nutrition and recovery, and you’ll be good to go.

 

As always, consume adequate amounts of protein, fats, and carbohydrates, get enough sleep, keep stress low, and prioritize recovery. Do this and muscle loss will not be an issue. 

 

Misconceptions About Training Fasted to Build Muscle

Insulin sensitivity, nutrient partitioning, and growth hormone

Many studies show that fasting can improve insulin sensitivity, enhance nutrient partitioning, and increase levels of growth hormone. These are three very important things to optimize if your goal is to build more muscle and improve your body composition.

 

Many people believe training after an overnight or 16-hour fast will improve their body composition due to better insulin sensitivity, nutrient partitioning, and a boost in growth hormone.  The only problem is that most of these studies require their participants to fast for 24 hours, sometimes even 48 hours or more. This study showed a significant increase in growth hormone levels after a 24-hour fast. Chances are you won’t be going into each workout after at least a 24-hour fast. Even if you did, there’s a very good chance your performance would suffer. It would be extremely difficult and uncomfortable to eat enough food to fuel a training session 24 hours later. An overnight fast is one thing, a 16-hour fast is getting up there, a 24-hour fast or more is less than ideal for muscle growth.

 

So, the key point to take away here is that even though nutrient partitioning, insulin sensitivity, and growth hormone levels may be slightly elevated after an overnight or 16-hour fast, it’s nothing significant. The effects are negligible and it’s highly unlikely it’ll help you gain more muscle mass. Have you ever heard someone not eating to maximize muscle growth? No, it’s the opposite.

 

To maximize the benefits of a fast, you should aim to fast for at least 24 hours. If your goal is to build a more muscular and leaner body, you’ll probably never find yourself fasting for that long. You’d be better off eating on a regular basis with enough of each macronutrient, having a variety of nutritious foods, and sleeping well. There are other ways to improve insulin sensitivity and nutrient partitioning that don’t involve fasting. And for elevated growth hormone levels to make a significant difference, you’d probably need exogenous growth hormone to inject to reach supraphysiological levels.

 

Experiment and Compare

There’s only one way to find out if lifting fasted is for you. Try it yourself and compare the outcome to training in a fed state.

 

Pay close attention to how you feel, how you look, blood flow, energy levels, strength, stamina, and endurance. 

 

Give fasted training a week or two. Keep as many variables—sleep, training intensity and duration, water intake, psychological state, calories, macros, and food choices—the same so you can make an accurate comparison to find out what works for you.

 

Whatever you do, make sure you do not go into your fasted workouts with self-defeating thoughts. If you head to the gym thinking your workout will suck and you’ll have no energy because you haven’t eaten since last night, then your workout will probably suck. Your thoughts are powerful. Get in the right state of mind, be ready to train, and give it your all. 

 

My Experience with Fasted Strength Training

At one point in time, the idea of waking up in the morning, not eating anything, and heading to the gym to train sounded absolutely crazy. I thought my strength and power would suffer. I didn’t think I’d have the endurance and energy to power through my workouts with a high level of intensity. I thought the quality of my workouts would be terrible and I’d feel awful.

 

It all started one night when I went out to a restaurant for dinner (I think it was Cheesecake Factory). I ate quite a lot—an appetizer, entrée, helped finished my girlfriends dinner, and finished off with dessert. I was completely stuffed, on the verge of being uncomfortably full.

 

I planned on working out the next morning. So, I thought to myself, “If I just ate this much, I probably don’t even need to eat breakfast tomorrow. This should be plenty of food to fuel the workout.”

 

I was right.

 

The morning after the big dinner with dessert, I woke up, drank plenty of water to get hydrated, and made my way to the gym. I started warming up, gradually increasing weight to work up to my first working set of my first exercise.

 

As I was doing so, I noticed I had a pretty good pump going just from the warm up.

 

As my workout went on, I noticed I felt a bit stronger than usual, the pump was great, and I looked great. I set some personal records and had plenty of energy to finish the workout strong.

 

After seeing such great results from a large meal followed by a fasted workout the next morning, I thought I’d give this a shot again to see if I could replicate the results.

 

So, once again, I ate a larger than normal meal about 2 to 2½ hours before bed. I woke up, drank plenty of water, and went to go train.

 

I had another awesome workout and replicated the results from last time. I looked great, felt stronger, and had no problem finishing my workout.

 

This is now something I do when it’s convenient and fits my schedule.

 

If you’re interested in lifting fasted in the morning, here are some suggestions I have.

 

✓ Fuel up the night before with plenty of food. This will require some experimenting on your part to find out how much food is enough for you. For me, my last meal can range from 1,000 to 1,700 calories. It depends on my appetite that day, how much I’ve had to eat earlier in the day, what foods make up the meal, and how many hours before bed I’m eating.

 

✓ Don’t shy away from dietary fat. Since fats slow down digestion, it’s typically recommended to consume small amounts of fat or none at all in your pre-workout meal. Since you’re eating your meal about 10 hours or even longer before training, eating fats won’t be a problem. Slowing down digestion when your workout is 10 or more hours away could actually be beneficial. 

 

✓ Eat plenty of protein and carbohydrates. Protein is key for keeping protein synthesis elevated and minimizing muscle damage and protein breakdown. Carbohydrates are necessary for keeping muscle glycogen stores full—your main fuel supply for resistance training.

 

✓ Make sure you don’t eat too much too close to bedtime. I did recommend eating a larger than normal meal the night before, but be careful. You don’t want to get into bed and realize you’re way too full to get comfortable, fall asleep, and stay asleep. This will require some trial and error to get right. You want to eat enough, but not to the point where sleep quality declines. For me, eating 2 to 2½ hours is ideal.

 

✓ Wake up and drink plenty of water before heading to the gym. I typically shoot for six 8 ounce glasses of water before training on an empty stomach in the mornings, and continue to drink water throughout my workout.

 

✓ Consume your post-workout meal shortly after training. Your post-workout meal becomes increasingly important the longer it’s been since you last ate.

 

Conclusion

I don’t do intermittent fasting or follow any religions that involve fasting, but I still train fasted in the mornings when it’s convenient.

 

And guess what? I’m still progressively getting stronger and gradually putting on quality weight.

 

By training fasted in the morning, I can wake up later and not worry about breakfast. If I wanted to eat a decent sized breakfast, let it digest, then go train, I’d have to wake up around 3:30 AM, no later than 4 AM. 

 

Instead, I get to sleep in a bit later and still get a great workout in. 

 

For me, it’s all about convenience. Don’t expect any drastic body transformations by simply training fasted. I wouldn’t go out of my way to train fasted, but when it fits nicely into my schedule, I do it. 

 

If you find it’s convenient for you too, give it a shot and let me know how it goes. 

 

Drop a comment below or shoot me a message me here on Instagram. I’d love to hear from you.