What Makes Muscles Grow Faster? The Science Behind Muscle Growth

There are many health benefits to building muscle. Increasing your muscle mass can help boost your physical performance, athletic prowess, and fat and weight loss, in addition to improving your resting metabolic rate, increasing bone density, improving your functional and mental health, and reducing your risk of chronic illnesses (1).

In addition to the health aspect, increasing muscle mass can also help you look good, which may improve your self-esteem. Regardless of why people choose to increase their muscle mass, the question of what makes muscles grow faster is something that many people who are looking to bulk find themselves asking. 

Read on to get tips on how to increase muscle mass fast and healthily.

What Causes Fast Muscle Growth?

The quick and simple answer to this is diet and exercise routine. When done the right way, a combination of these two factors can help you start to see signs of gaining muscle faster than you think.

However, the longer answer is a little more complicated. You need to remember that just like fat and weight loss, the rate of muscle growth is affected by multiple factors. These include training intensity and volume and your genetics, age, overall calorie intake, and hormones (2)

While there isn’t much you can do about factors such as your genes, age, and hormones, factors such as calorie intake and diet and training intensity and volume are things you can control. These are what we’ll be looking at today.

What Helps Grow Muscle Faster?

So what makes muscles grow faster naturally? As stated above, your diet and exercise routine are the two main things you can work on to help increase the rate of your muscle growth. 

Let’s take a closer look at each factor and what you need to do and change to increase this rate.

Diet

There are many components that make up nutrition for each individual. When looking at someone’s diet, it’s typically easiest to look at it from a bigger perspective. Here we will divide this into two parts: your overall calorie intake and your macronutrient intake.

• Your Overall Calorie Intake

Generally, people who are looking to increase muscle mass are often advised to start eating at a calorie surplus, which simply means eating more calories than your body burns a day.

The main reasoning behind this is that bulking, or rather increasing muscle mass, requires more intense resistance training and the extra calories provide the fuel that is needed to do this. 

In a review published in 2019, researchers stated that during the off-season, bodybuilders increase their calorie intake by 10% to 20% which helps them increase their weight by 0.25% to 0.5% a week, depending on whether they are novice or intermediate bodybuilders (3).

If you already count your calories and have a good understanding of how many calories your body burns in a day, add an extra 10% of your regular intake and this should be your new daily intake as you work to increase your muscle mass. 

If you don’t count calories, use a reputable calorie-counting app – the BetterMe app is a great example – to track your regular calorie intake for about a week. Find the average, add 10%, and make this your new intake.

Please Note:

Eating at a calorie surplus typically works best for those who are currently happy with their weight or even those who are underweight and want to gain muscle. If you’re wondering how to build muscle fast and lose weight, a calorie surplus isn’t the thing for you.

Anyone who hopes to increase muscle mass but also lose fat/weight should eat at a calorie deficit. If they eat at a calorie surplus, they will simply gain more fat even if they’re working out at the same time because their body is still unable to burn the extra food energy intake.

Instead, they should eat on a deficit, which means they are eating fewer calories than their body uses up in a day. This forces their body to turn to burning stored fat as an energy source, which leads to fat and weight loss over time. Experts recommend a daily deficit of 500 to 700 calories (4).

• Your Macronutrient Intake

Macronutrients or macros as often referred to in the fitness world refer to your intake of carbohydrates, protein, and fats. 

Carbohydrates and fats are important in any bulking plan. The former are turned into glucose and stored in the muscle then later used as fuel while exercising, and the latter are essential for reducing inflammation in the muscles, acting as a source of long-term energy for the body and for hormone production. 

Ordinarily, the recommended macro intake for a balanced diet is 45% to 65% of your total calories from carbohydrates, 20% to 35% from fat, and 10% to 35% from protein (5). However, studies have shown that for bodybuilding, a higher protein intake works best (6, 7). 

These researchers recommend that you instead consume 55% to 60% of your total calories from carbohydrates, 25% to 30% from protein, and 15% to 20% from fat (6). 

It should be noted that if you prefer to measure your protein intake in grams, researchers have stated that the best protein intake for muscle growth is an intake of 1.2 g to 1.6 g of protein per kg of body weight per day (6, 8, 9).

Learn more about mass-gaining diet plans for a better chance of success.

BetterMe: Health Coaching app helps you achieve your body goals with ease and efficiency by helping to choose proper meal plans and effective workouts. Start using our app and you will see good results in a short time.

Exercise Program/Routine

Once your diet has been sorted, the next thing to look at is your workout routine. For this, you’ll need a resistance training routine and rest.

• Resistance Training

Also known as strength training or weight training, this is a form of exercise that makes your muscles work against a weight or external force, which breaks said muscle down, and after recovery, the muscles in question grow stronger and bigger.

Studies over the years have shown that of all exercise types – cardio, resistance training, balance, and flexibility exercises – resistance/strength training works best for increasing muscle mass and strength (10, 11, 12).

Strength training can be done either using free weights, gym machinery, resistance bands, or simply your body weight. If you’re curious about how to gain muscle fast at home, a high-protein diet plus an at-home strength training program that uses your body weight or with the help of resistance bands can see you well on your way to meeting your desired goals.

Our previous post goes into great detail if calisthenics build muscle.

• Rest

It may seem counterintuitive to be required to rest when we know that exercise helps build muscle, but what you may not realize is that muscle grows when you allow it to rest.

As previously mentioned, the strain of working out creates microscopic tears in the  muscle fibers. If you continuously exercise without ample rest, you’ll overwork these muscle fibers, which can weaken  them and ultimately increase your likelihood of injury  – it may even affect your mental health too (13).

However, when you rest (and eat enough protein), you allow the muscle fibers to repair themselves, recover, and rebuild. This makes them stronger for the next workout session and after enough time (plus rest and protein), they’ll start to get bigger.

Ensure that you get a full 24-48 hours of rest per week to allow the muscles to rest and recover. Remember, you can always do passive and/or active recovery.

Read more: Is working out 6 days a week too much

Can You Speed Up Muscle Growth?

Yes, you can. As mentioned above, a combination of strength training and a high-protein diet works best for fast muscle growth.

Here are some tips on how to train for fast muscle growth:

• Increase Training Volume

Researchers seem to be in agreement that increased training volume, i.e. more sets and heavier weights, seems to work best for muscle hypertrophy (aka increased muscle mass). 

Therefore, if you’re using weights in your workout, try going heavier, but make sure you pace yourself so you don’t injure yourself, especially if you are a beginner. 

Regarding the number of sets and reps, researchers state that you should perform anywhere between 3 and 6 sets with 6 to 12 reps per set for the best results (10, 11, 12, 14).

• Practice Progressive Overload

This ties in with the point above. Progressive overload refers to the act of gradually increasing the intensity, duration, and volume of your workouts. 

The theory behind this is that when you constantly challenge your muscles, they’re forced to constantly break and repair, which helps them get bigger and stronger.

In resistance training, progressive overload can be done by increasing the workout duration, weights used during workout session, number of sets or reps per workout, and reducing rest time in between exercises (15).

Do Muscles Grow on Rest Days?

Yes, they do. Rest days allow the broken muscle fibers to repair themselves and recover, which makes them grow bigger and become stronger.

What Is the Fastest Muscle to Grow?

Some sources claim that the lower-body muscles grow the fastest while others claim that chest muscles or the shoulders grow quicker. However, these claims seem to have no scientific research to back them, so we can’t say if this is true or not.

What we can do is remind you that muscle growth is also influenced by your genetics. Therefore, the best way to try and determine which of your muscles may develop the fastest is to look at your family members. Whichever muscle grows the fastest on them will likely grow the fastest on you too, but this isn’t always the case as we’re all incredibly unique individuals and even with similar genetics, there can be drastic differences in how the body builds muscle or is shaped.  

When it comes to weight loss, progress is made by inches, not miles, so it’s much harder to track and a lot easier to give up. The BetterMe: Health Coaching app is your personal trainer, nutritionist, and support system all in one. Start using our app to stay on track and hold yourself accountable!

Why Am I Getting Stronger But Not Bigger?

You may need to change your training regimen. Instead of lifting heavy and doing smaller reps, try lifting lighter weights and doing more reps. Consider taking longer breaks between sets. This may help you increase muscle mass.

Read more: Beginner Cardio Workout: The Ultimate Guide To Getting Started At Home Or The Gym

How to Bulk Fast in a Healthy Way 

The trick remains the same – exercise and a high-protein diet. Your protein sources for this should be from animals and plants.

Animal protein sources include lean meats, poultry and eggs, fish and seafood, dairy products, and whey protein powders. Plant-based protein options include beans, peas, nuts, lentils, seeds, soy products, and plant-based protein powders. 

In addition, eating at a calorie surplus doesn’t mean you need to eat junk food to hit these high calorie totals. You should look for nutrient-dense foods and continue focusing on healthy eating habits even when you’re trying to get those calories in. 

Frequently Asked Questions

• Can fat turn into muscle?

No, fat doesn’t and can’t turn into muscle. These two are made up of different cells and so one cannot turn into the other. 

• Is rice good for bulking?

Yes, it is. As mentioned above, carbohydrates are essential for a bulking program as they are turned into glucose that fuels the workout. Rice is a fantastic and easily available carb source.

• Is dirty bulking faster?

Not necessarily. Dirty bulking means that you’re consuming your calorie surplus through unhealthy foods that aren’t very nutritious and are high in simple carbs and unhealthy fats. 

However, at the end of the day, 3,000 calories is 3,000 calories. You can likely get 3,000 calories of junk food down quicker than 3,000 calories of healthy foods, but junk food won’t provide you with the other nutrients your body needs in order to feel good and function as it should. 

While this can help you get to your target weight faster, it also means that you’re also more likely to increase your fat percentage. Ultimately, you’ll have to work harder to lose the accumulated fat. 

Simply stick to clean bulking – it may take longer and have you eating a larger portion of food at a time, but you don’t have to suffer in the gym getting rid of extra body fat and you’ll likely feel better overall. 

• Is it better to be lean or bulky?

Neither is better or worse. It all comes down to personal preference. If you feel like a bulkier physique is better for you, then go for that, and if you believe that being leaner is preferable, then go with that. Focus on what your individual goals are and what you want to accomplish on your wellness journey. 

• How can skinny guys gain muscle fast?

There’s no trick for this. You’ll need to eat at a caloric surplus and do more resistance training workouts. Practice progressive overload to help you lift heavier and grow stronger and bigger.

The Bottom Line

The answer to ‘what makes muscles grow faster?’ is simply diet and a good weight training program. As long as you understand what and how much of it to eat and how to train, the results will come. Just be patient and remember that while pushing yourself is good, pushing too hard can be detrimental. Pace yourself and remember to rest. Your muscles won’t grow without proper food intake or rest, so get enough of both.