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Muscle Building

Much has been written about gaining muscle size. But all the advice you need boils down to two simple things: if you want to build muscle, you need to train in the right way and give your body the right type and the right amount of fuel.

The human body is made up of three different types of muscle, but the one that concerns sports people and body builders is skeletal muscle. These muscles – which are made up of long, thin fibres bound together by connective tissue – are attached to your bones by tendons. And unlike the other two types of muscle – namely cardiac and smooth muscle – skeletal muscle is controlled by nervous system cells called motor neurons, which is why it’s often also sometimes called voluntary muscle.

When you overload your muscles while performing strength exercises (such as lifting weights etc) tiny tears appear in the muscle fibres. After your workout, your body repairs or replaces those damaged muscle fibres by fusing the fibres together. The repaired fibres multiply and become thicker, creating muscle hypertrophy – or, in other words, muscle growth. So the process of creating bigger muscles actually happens while you’re at rest, rather than when you’re working out.

To overload your muscles so that the building process will take place, you have to put a lot of stress on them – that is, more stress than they’re used to. This explains why sports people and body builders lift progressively heavier weights – if they don’t, their muscles do not become stressed. And if their muscles aren’t stressed, they don’t get any bigger. 

How to train

If you train hard and smart enough, there’s no reason why you shouldn’t experience noticeable muscle gains in a relatively short period (some people see gains – either in the size of their muscle or the amount of weight they can lift with ease – in a few weeks while for others it could take a few months).

But the good news is you don’t have to spend all day, every day at the gym. Many fitness experts recommend doing as little as 20 minutes or up to a maximum of 40 minutes of strength training exercise just two or three times a week.

Working out with free weights isn’t the only way to boost your muscle strength. You could also use weight machines or work out with a resistance band. Exercises that use your body weight as resistance – such as push-ups, pull-ups, squats and lunges – are also ideal strength training activities.

Whatever type of strength training you do, always try to warm up for at least five minutes beforehand – do some type of aerobic exercise such as marching on the spot or skipping to make sure your muscles are warm before you put them under stress. If you’re using weights, use light ones when you start strength training and increase the amount of weight gradually (don’t lift very heavy weights too soon or you may risk an injury). Aim for the amount of weight that tires your muscles after about 12 to 15 repetitions (reps), and use a controlled motion – don’t swing the weight in an uncontrolled manner.

As for which muscles you should concentrate on in a workout, experts are divided on whether you should work every muscle in a single session or split your workout so you strengthen your upper body muscles one day then your lower body muscles another day. Both types of workout are thought to have their advantages, so choose the one that suits you best.

Cardio or no cardio?

Many people whose fitness aim is to build muscle think aerobic exercise – or cardiovascular exercise – should be avoided because it prevents weight gain. But experts now believe it can help with muscle growth, as well as give your heart and lungs a workout. However, try to keep your cardio training light and limit it to about 30 minutes a session.

One final aspect to your training should be stretching, as it helps keep your muscles flexible and increases the range of movement in your joints. Making sure you get adequate rest between training sessions is also crucial, as this is when your muscles repair themselves and grow bigger.

What to eat

To gain muscle you have to gain weight, and the only way to achieve this is to eat a sufficient number of calories – that is, more calories than you burn – each day. One way to do this is to eat five or six smaller meals instead of your usual three. How many extra calories you’ll need will depend on how much weight you want to gain, how fast you want to gain it and how lean you are to start with.

You’ll need lots of good-quality carbs to give you the energy you need for your workouts, so make sure you eat plenty of whole grains. Also fill up on protein, as protein helps repair your muscles after a workout. Some fitness experts believe animal-sourced protein such as meat and dairy products is best for building muscle, but getting a good supply and variety of plant protein can help increase muscle mass too, including foods such as beans, pulses, nuts, seeds, tofu, Quorn, seitan and tempeh.

Protein shakes are also a convenient way of boosting your calorie and protein intake. These are particularly useful to have after a workout, as experts recommend having some protein and carbs within 30 minutes after a strength training session if you want to maintain or increase your muscle mass. Whey protein powder is ideal, as whey contains fast-acting proteins that get into your muscles quickly, helping them to heal and increase in size. 

Fats are also important, especially if you’re aiming to gain muscle. However, make sure you eat the right type. Try to include some ‘good’ fats (or unsaturated fats) in your diet, such as those found in oily fish, extra virgin olive oil, nuts, seeds and avocados. If you don’t like eating fish, you may want to try a good-quality fish oil supplement to make sure you’re getting an adequate supply of healthy omega-3 fats.

Should you take a supplement?

There are several supplements marketed at people who want to build muscle. Here are some you should know about:


An amino acid produced in the body from other amino acids, creatine helps supply muscles with energy (95 percent of the creatine in your body is found in muscle tissue). Food sources include meat, fish and poultry. Several studies suggest creatine supplements may improve muscle strength and endurance, especially during activities such as weight lifting and other high-intensity exercise of short duration (i). There’s also evidence it helps boost muscle mass when combined with strength training (ii).

Creatine may also be a particularly useful supplement for people who don’t eat many foods that contain creatine, such as vegetarians (those who don’t eat fish or meat are often found to be low in creatine).

Branched-chain amino acids (BCAAs)

BCAAs consist of three individual amino acids – namely isoleucine, leucine and valine, all of which your body cannot produce (these amino acids are also thought to be the most important for muscle repair). You can find them in many protein sources, particularly animal sources such as meat, dairy foods, eggs, fish and poultry. BCAAs are needed for making protein and stimulating muscle production in the body. There’s also evidence taking a BCAA supplement may help reduce or delay muscle soreness and improve muscle recovery (iii).

Weight gainers

If you’re finding it difficult to build muscle, you may need a product called a weight gainer (sometimes also called a mass gainer). Weight gainers usually come in the form of powders that you make into a drink that provides you with protein and carbs. These convenient drinks can be particularly useful if you’re struggling to get the amount of calories you need to gain weight from food. Having a weight gainer drink is also an ideal way of taking on more carbs and protein directly after having a workout.


Another amino acid, arginine (or L-arginine) is also a favourite supplement with athletes and body builders. It may be particularly useful as a pre-workout supplement as it’s needed to help relax blood vessels, which may boost performance and improve recovery.


  1. , et al. Creatine Supplementation and Lower Limb Strength Performance: A Systematic Review and Meta-Analyses. Sports Med. ;45(9):1285-1294.

    Upper Limb Strength Performance: A Systematic Review and Meta-Analysis. Sports Med. ;47(1):163-173.

    , . Creatine supplementation during resistance training in older adults-a meta-analysis. Med Sci Sports Exerc. ;46(6):1194-203.

  2. , . . Effect of dietary supplements on lean mass and strength gains with resistance exercise: a meta-analysis. J Appl Physiol (1985). ;94(2):651-9.

  3. , et al. Diet and its relationship with grip strength in community-dwelling older men and women: the Hertfordshire cohort study. J Am Geriatr Soc. .56(1): p. 84-90.

  4. , , , . Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system. J Sports Med Phys Fitness. ;48(3):347-51.

Our Author - Keri Filtness


Keri Filtness has worked in the Nutrition Industry for 19 years. She is regularly called upon for her professional comments on health and nutrition related news. Her opinions have been featured by BBC3, Prima, Vitality, The Mirror, Woman’s Own and Cycling Weekly, amongst others. She has also worked one to one with journalists, analysing their diets and health concerns and recommending changes and additions, where appropriate.

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