Do Bodybuilders Fast?

Fasting has always been a highly debated topic in the bodybuilding community. Almost an equal number of supporters seem to be both for and against it.

Diet is the cornerstone of bodybuilding. As a serious bodybuilder, you want to shed fat and gain muscle. At some point you might have to fast, it could be for religious or medicinal reasons.

So, do bodybuilders fast? Well, yes. Many bodybuilders actually fast for religious and medical reasons, and to lose weight before a competition! However, fasting should be avoided if possible as you can lose a lot of muscle when fasting. So, if you’re fasting, try to eat amino acid supplements every day- as this usually doesn’t interfere with a fast as it’s not food and basically just water.

Fasting while bodybuilding is complicated. Should you work out while fasting? Is it okay to fast while bodybuilding?

The answers to these questions are not as simple as they might seem at first. Let us try to understand the problem better and help you fast the best way, no matter your goals.

Do Bodybuilders Fast?
Do Bodybuilders Fast?

Do Bodybuilders Fast?

There is no definitive answer to the question. For the majority of bodybuilders, fasting may not be a regular activity that they actively engage in. There are different reasons for this which we will get into in a later section.

There might be times when you must fast, it could be due to religious obligations or medical reasons. For some, it’s a choice. Some bodybuilders fast on their ‘cut‘ to lose fat, in fact- “Intermittent Fasting”- the act of only eating within a small time window every day is very popular in the bodybuilding world.

Let us try to examine if it is a good idea for bodybuilders to fast or not.

Effects of Non-Eating on Bodybuilding

Evolutionary speaking, our bodies evolved to survive without food for long periods of time. Going days without food or anything of the sort is a common happening in nature.

Living multiple days without food is still very much a part of the lives of many tribals. When we are fasting, we are trying to recreate similar circumstances so our body feels more “natural”. Let us what the direct effects of non-eating are on bodybuilding:

Low Energy

Carbohydrates are the main source of energy for the body. Food that we eat gets converted into energy and is used to do all kinds of work in the body, including lifting weights.

Not eating for many hours leaves your body deficient in energy. This means your performance will be decreased than before.

Low energy might also interfere with blood sugar levels. This also puts a limit on how much you can push your limits – not having enough energy will also kill your willpower sooner.

A Protein Deficient Body

Similar situations arise for proteins. When you are bodybuilding, you want to do the following:

  • Burn the fat 
  • Increase muscle size by overload exercises and increasing protein intake
  • Increase the amount of work you can do by increasing carbohydrate intake

Fasting directly affects the second objective, just like it does the third. While your muscles won’t die because of a few days of fasting, the growth definitely goes down.

Gaining muscles basically means you are working the muscle fibers and feeding them tons of proteins. Not eating enough proteins means your fibers do not get the added benefit of growth.

Fat Reduction

This is an advantage of fasting. Starving the muscles of energy means the body has no choice but to convert existing fat into energy.

So the metabolic processes start consuming body fat for energy needs, leading to a reduction in fat. Fasting, therefore, is a great way of getting rid of a lot of body fat. If you are big and need to lose a ton of fat quickly, fasting and dieting wisely is one of the best ways of reducing your weight. 

Can You Gain Muscle While Fasting?

When you are fasting, you are purposely cutting down the nutrients. The two macronutrients – carbohydrates and proteins are absolutely essential for gaining muscles.

If you are not eating more than what you consume, unfortunately, your body simply won’t have any nutrients left to grow the muscles. In other words, growth of muscles will be hindered by the limited protein intake. 

According to a study conducted on a randomized group of males, the males that engaged in intermittent fasting gained less strength than the non-intermittent fasting males. This could be extrapolated to the different kinds of fasting. Fasting can, therefore, stop you from gaining muscles. 

Another study conducted on middle aged adults shows that reduced meal frequency without caloric restriction leads to difficulty in getting enough calories. This means that fasting will make it harder for you to stick to your workout plan and you are more likely to decrease workout or skip days when fasting.

If for some reason, you absolutely have to fast, the following points will come in handy:

  • Consider eating a bit extra on the meals you take in between the fasting. Topping your platter with extra carbs will help you pull through your full workout routine. 
  • If your fast allows them, protein drinks or amino acid drinks will help avoid delays in gaining muscles. They will provide the muscles with much needed proteins for muscle repair and development. 

When and When Not To Fast

Fasting does have its benefits that cannot be denied. However, as we have learned, it might not always be the best decision to fast. Here we help you decide when it is good to fast and when it isn’t.

When it Helps To Fast

  • If you are overweight, and need to get rid of fat fast. Fasting forces your body to use the stored fat as a source of energy. Leading to burning of calories at a faster rate.
  • If you are facing medical problems relating to the bowels, the digestive tract or if advised by a medical health professional.

When It Doesn’t Help So Much 

  • You should absolutely not be fasting if you already don’t have body fat.
  • It does not make much sense fasting if you are trying to gain muscle.

Summing it up, we can say that fasting reduces the intake of important macronutrients that your body needs. So unless you are very heavy and need to get rid of a lot of fat, or have a medical condition, that forces you to fast, you should not be fasting.

Trying to gain muscle while fasting only exhausts your body while delaying the results.


As a serious bodybuilder, fasting is something that you want to avoid. We discussed the many ways in which fasting can hinder body growth, meaning even if you worked out fasted, you won’t see any results.

You want to feed as much protein and carbohydrates to your muscles as you possibly can. That, and a suitable workout routine is what you need to make those gains.

If you have to fast, try eating amino acids every day as usually this doesn’t ‘break the fast’- as it’s zero calories and just like nutrients. This will help reduce muscle loss during your fast.

But at the end of the day, most fasts won’t result in huge muscle loss, typically only fat loss. Try not to fast for too long, respect the reasons why you do the fast, and always consult with a medical professional before fasting to ensure your health is safe.

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