Does fasting affect your lifting? – Fasted lifting examined

Will intermittent fasting reverse the muscle gains, and is fasted lifting really a thing? How can we incorporate intermittent fasting and lifting based on our goals?

Fasting gained popularity as a last resort to intensively lose fat over the short time period. It’s no coincidence that intermittent fasting is one of the most popular diets today.

We’re witnesses that many fitness bloggers and public personalities tried and succeeded to bring down their body fat just by fasting.

But, the majority of these people are not bodybuilders, and what is concerning is the question does fasting affect your lifting?

Let’s find out.

Will you lose muscle when fasting?

Portrait of attractive young sportswoman training arms muscles in gym

Every study that has been done on the subject of intermittent fasting had the goal to create an effective way to lose weight.

Even though some studies have shown no loss of muscle mass, essentially intermittent fasting causes loss of both fat mass and lean mass.

But, the probability of lean mass loss is minimal, you can only lose a maximum of 2 pounds of lean mass after several months of fasting.

Most likely you won’t lose muscle mass when fasting if you’re lifting.

Some researches even believe that intermittent fasting is effective for maintenance of muscle mass than any other diets that don’t include fasting.

Understanding types of intermittent fasting

Intermittent fasting describes a number of different diets. It’s important to tell them apart.

Here are some examples:

  • Periodic fasting

Periodic fasting is a program of few occasional fasts. It’s a program of whole day fasting a few days a month.

Usually, it’s one or two days every other week. The program varies from one to four weeks between fasting days.

  • Restricted eating

Restricted eating is one of the most popular fasting schemes. It defines restriction of calories to a certain amount for one part of the day.

The 8-hour fasting period is the most common, but the program ranges from 4-12 hours.

  • Alternate-day fasting

To put it the simplest way possible, this diet defines fasting every other day. This type of fasting has variations of its own.

It can mean you should use true fasting on fasting days (meaning no meals at all) or you can have one small meal on the fasting day, usually breakfast.

  • Religious type of fasting

Many religions have some sort of fasting periods.

These types of fasting vary depending on the religion and the cause.

These periods are usually long, but not that restrictive calories-wise, most of them restrict you only from certain foods.

  • The 5:2 fasting

Similar to periodic fasting and alternate day fasting, the 5:2 diet involves taking 2 days of the week and eating only a quarter of your normal calorie intake on those two days.

It’s sort of modified fasting, and these types are among the less effective diets because they don’t involve true fasting.

Should you fast if you want gains?

Closeup portrait of a muscular male chest with barbell in gym

There are not enough researches being done on the subject of muscle gain while fasting. This is most likely the case because the end goal of all fasting diets is weight loss.

But, there is one research on the subject with a focus on time-restricted diet and resistance training.

While testing the group on time-restricted diet, there was no muscle gain noticed, contrary to the control group who gained 5 pounds of lean mass.

This research directly implies, along with other scientifically backed reasons, that fasting is not an optimal diet for muscle gain.

Intermittent fasting is contrary to the muscle gain formula, which is eating more calories than you can burn, stimulating the muscle with resistance training and taking enough protein to build new muscle tissue.

Although it’s not impossible, it can be quite difficult to eat enough protein when you less often than you normally do.

Could it be done? Sure. Should you put yourself to that type of torture if you want to gain muscle? Probably not.

Take one step at a time. Use fasting when you want to lose body fat and maintain your current muscle mass, not when you want to gain it.

In the case of fasted lifting vs fasted cardio for maintenance of muscle mass, it’s better to use fasted lifting.

Should you lift while fasted?

There’s a never-ending debate on this subject. Luckily, few studies have been done to look deeper into this.

In the mentioned study, both the test group and control group kept their lean mass, but the test group lost some percentage of body fat.

Fasting did have an impact on the performance of the test group. So you can expect a decrease in your performance while fasting.

Bottom line, it’s a personal preference, but you are safe to exercise fasted if you wish to do so.

How to maintain your current muscle mass when fasting

It’s inevitable to lose both fat and muscle mass when fasting. Unless you do something to keep your current lean mass at a level, it is now.

Stimulating the muscles with resistance training is a good way to prevent lean mass loss when fasting.

This is exactly why fasted lifting is the best program to maintain your lean mass and lose body fat.

There is a specific study done on this topic with experienced weightlifters.

Two groups of people were studied, one on a restrictive diet and the other on a regular one. Both groups maintained their strength and lean mass, but the group who was fasting lost 3.5 pounds of fat.

So, to maintain your muscle mass while fasting, resistance training is a must, and those meals that are included in the program should be high in protein.

Nutrition plan for fasting

Meal plans

So we covered that you should do fasted lifting to maintain lean mass, now it’s time to lay down some base for nutrition for those fasting days.

The capability to burn fat varies from person to person. If you know you’re prone to losing mass quickly, you should consider starting slow and gradually decreasing your calorie intake.

Keep track of your weight loss, the recommended amount of weight loss is 1-2 per week. But if you want to preserve your lean mass and you’re prone to burning fat quickly, you should go for the lower range.

Regardless of the type of fasting diet you go for, make sure your protein intake is in check. You don’t have to follow the standard rule of 2 grams per kg of your body weight, 1.5gr will be enough.

Bottom line, you should only consume protein and water while fasting.


There are two most important supplements while fasting; these two are generally the most important supplements for resistance training overall.

Whey protein and creatine.

Our recommended whey protein. (remember to select the flavour you want)

Our recommended creatine.

Whey protein is the easiest to consume and digest, and it will help you keep your appetite low and your muscles fed.

Creatine is needed for your training days to keep your muscles from getting into catabolic state.

But, keep in mind that you should take these supplements on your feeding days.

If you’re fasting period is 16 hours, or any other period of time, don’t consume anything, not even the supplements.

If you take supplements on those days that are meant for fasting, you won’t get the desired effect, because your body won’t get the signal that you’re fasting because you gave it nutrients that it needs, and it won’t try to replace them with the ones stored in your body.

The response of your body on fasting

Intermittent fasting has a direct impact on your hormonal balance.

When you start fasting period, your body starts to break down stored fat and use it as energy. It also tries to maintain the blood sugar level.

There are 3 hormones that increase your blood sugar level:

  • Cortisol
  • Growth Hormone
  • Glucagon

When your blood sugar level drops, your body starts to release Cortisol to maintain a stable sugar level.

Cortisol is catabolic and will break down muscle and make it hard for you to build new muscle tissue. This is why it’s important to have plenty of protein in your feeding days.

Growth Hormone, however, has an anabolic effect, especially when your insulin level is high. Growth Hormone is very useful when lifting, but you probably know that already, so when you fast, then feast and lift, you will counter the negative effect of Cortisol on your muscles.

Maintaining your lean mass in the process of fasting is the most important thing, and this is how you do it.

Pros and Cons of intermittent fasting

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  • It stimulates the detox of the body
  • It rests the body and heals the stomach
  • Significantly rests your brain and clears your mind
  • It can have an anabolic effect after you’re done fasting
  • It lowers your blood pressure and heart rate
  • It’s the most effective way to get rid of the unwanted body fat


  • Possible muscle loss if not used properly
  • Low energy levels (at the beginning of the cycle)
  • Lower strength (if you don’t lift during fasting program)
  • Vitamin and mineral deficiency
  • Higher chance of injury
  • Lower metabolism
  • It can cause depression if used for too long

In conclusion

To summarize everything we know so far; does fasting affect your lifting? It does not if you lift during your feeding days and if you don’t fast for too long.

It has a lot of benefits, especially when you finish the fasting cycle. Your body fat will be lower, and you will have a short period of anabolic boost, due to the Growth Hormone being released in the fasting period.

Give it a go, but make sure do it as you were instructed above, if you want to lose only the fat and not your muscle gains.

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