Does Intermittent Fasting Cause Muscle Loss

Does Intermittent Fasting Cause Muscle Loss

If you hit the gym and your main goal is to build muscle, you might be worried about trying intermittent fasting. A big question many people have is does intermittent fasting cause muscle loss. This article will explore and hopefully explain further how intermittent fasting and muscle loss interact.

If the first thing you thought of when you heard intermittent fasting and learned it meant not eating was whether or not does intermittent fasting cause muscle loss you aren't alone.

As a society and especially as a fitness community, we've been told time and time again that you have no choice but to eat multiple times a day in order to make sure that you don't lose muscle gains that you've earned in the gym.

But fear not, or maybe fear a little? It's up to you. Let's take a look and answer the question, “does intermittent fasting cause muscle loss.”

The truth about muscle loss food timing and calorie intake

Does intermittent fasting cause muscle loss? Great question when you consider that it's common sense that muscles require food to grow and survive.

What is less understood is how the body maintains and processes muscle.

So we can better understand what actually happens when you don't eat, we need to understand the order in which the body processes food and how it prefers to use fuel.

It takes time for the body to break down protein, and it does not do so without putting up a fight, so to speak.

After eating your last meal, you will process carbohydrates, followed by stored carbohydrates in the form of muscle glycogen, and eventually fat cells with some protein (muscle).

The following chart will give you an idea of how long these processes work, and more can be read at this site here.

chart showing time to use carbohydrates fat protein muscle for fuel

Summary - our bodies prefer carbohydrates and fat as fuel, and only use protein (muscle) as a last resort after many days of literal starvation.

How Long Can We Stay Fasted Without Losing Muscle

Studies have shown that your body can maintain itself for at least 24 hours without any negative consequences. This of course will depend on how much fat you have on your body, with people who have more fat to burn able to go for longer periods without worrying about muscle loss.

People adhering to an alternate day fasting type regime (where no food is eaten for 24 hours, followed by a regular day of eating) lost virtually no muscle mass over a four week period. This shows that fasting for 24 hours will not “eat away at muscle” at all, and is a safe practice for most people[]

Summary - Studies show most people can stay fasted upwards of 24 hours without negative impact.

Fasting then is Practical for Most Regular People

Although a 24 hour fast will not negatively impact most people, it should be noted that athletes, or people with very demanding jobs will react differently to different types of diets. If you are someone who goes to the gym seven days a week and always pushes yourself excessively, or someone with an intense job like fire fighter or lumberjack, you would not want to go so long without protein (at least), and may need a more balanced budget.

This of course does not mean that you can’t fast for shorter periods, but it means that like any complex machine, the body needs certain types of fuel to function optimally.

Why is Muscle Loss Prevented

We touched upon growth hormone in our introduction to intermittent fasting article. GH or HGH as it is known, is responsible for preventing muscle wasting when we do not eat, and it increases when we are fasting. GH has been shown to increase, and it is a good thing because short periods of fasting combined with intense exercise and recovery time can result in not just the retention of muscle, but in increased fat burning, muscle growth and deeper sleep as well as cosmetic changes like brighter skin and nicer hair.

People use injectable growth hormone or supplements like MK 677 to boost their GH production to ensure they see the same or better benefits than you can get with intermittent fasting’s GH release increase.

Related - MK-677, growth hormone and blood sugar, is it safe?

Summary - Growth hormone increases with intermittent fasting, this helps you to prevent muscle loss during your fast.

Thoughts - Does intermittent fasting cause muscle loss

Although the idea of not eating seems daunting for people who put hard work and time into the gym, studies have shown that intermittent fasting is not the boogeyman that some think it is, and that you can stay fasted for as long as 24 hours without negative consequences.

  • The studies references in this article showed people staying fasted for 24 hours without muscle loss, however there are a few different things that should be observed.
  • Everyone in the studies referenced were eating maintenance calories. Eating a deficit for fat loss could result in muscle loss, but growth hormone will aid in keeping your muscle.
  • Different people with different training and lifestyles may need to make adjustments to how long they fast in order to ensure they are keeping their muscle during their fast.
  • Eating a calorie deficit that is too large will almost always result in muscle loss, unless you are using anabolic steroid drugs, so be careful when you set up your diet.

As with everything related to diet and fitness, we have different metabolisms and everyone will react slightly differently (yet largely similar) to different approaches. This article should help you to better understand and answer the question of does intermittent fasting cause muscle loss.

Questions or comments, send us a message or use the comment box on this page to give us your opinion.

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