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How to grow muscle

Picture of Orla Walsh, RD
Orla Walsh, RD
Orla Walsh is a Registered Dietitian and Physiologist. Orla is the founder of Orla Walsh Nutrition, she is the former performance nutritionist to the Irish Olympic team and is regular contributor for the Irish Independent newspaper, RTE and Newstalk FM.

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Lots of people want to grow muscle but aren’t sure how to grow muscle. They might want to do it for improved sports performance, for aesthetic reasons, to mitigate the muscle loss we are all at risk of with aging or to change their body composition for health reasons. So, what’s important to factor in if you want to grow muscle?

  1. Eating enough calories.
  2. Eating enough protein each day.
  3. Eating enough protein at meal times.
  4. Eating good quality protein.
  5. Eating protein before bed.
  6. Being consistent with strength exercise.
  7. Other factors.

Eating enough calories

It is possible to build/ gain muscle with a calorie deficit. The notion that we are either losing tissue or gaining tissue isn’t actually true. Research has disproven it. However, it takes a lot of work and isn’t as efficient. Nonetheless, if gaining muscle is your main goal, and you want to achieve it as quickly as possible, then enough calories (extra calories) is the smart way to go about it. You don’t need that much more, just a little bit. If you want to build muscle without gaining much fat, avoid a large surplus in calories. Once you have the protein spot on, the balance of the rest can come from fats or carbs, and that’s due to personal taste and medical history. That said, 1 gram of fat per kg of body weight is a healthy target.

Eating enough protein

The targets for protein were based on the average person, and what they need to eat to prevent being unwell. I don’t know about you but I’m not aiming to eat so that I don’t become unwell, but rather eat to become more well! Basically, you don’t want to lose, but you also want to win. Protein requirements depend on goals, age, size, activity levels and whether you’re eating a plant-based diet or not. We have many ways of looking at it which include targets based on size e.g. 1.6 to 2.2 grams of protein per kg and targets based on calorie intake e.g. 15-30% of the calories coming from protein.

Eating enough protein at meal times

Usually, people need to eat 3 to 6 times a day. A big player here, other than size, is age. It might take 10 grams of protein to stimulate a young persons muscles, and 20 grams to stimulate their muscles to grow at their max pace. However, it takes 10 grams of protein to stimulate an older persons muscles to grow and 40 grams to stimulate their muscles at their max pace. So older people need twice as much to achieve the same thing. If you’re asking yourself if you’re considered old, the answer is probably, the research is offensive! Now, we also need to tailor this to the person’s size or else we’re suggesting a smaller, frail women/ man needs to eat as much protein as a bigger, active woman/ man. That would be silly. Other things matter here too such as medical history and whether weight loss is a goal.

The quality of the protein

Proteins are like pearly necklaces. Each pearl is an amino acid, and each protein differs in how long it is, what pearls it contains, and what pearls sit next to each other. Higher quality proteins are similar to the muscle proteins in the body. Generally, but not always, animals proteins are higher quality than plant proteins.

Not only are they similar to muscle, they are also high in a particular type of amino acid/ pearl called leucine. How I would explain leucine is that it’s the switch that needs to be turned on to trigger our muscles to build at their fastest pace. Or put it another way, if a builder is building a house, it’s the coffee you feed them to make them build faster! You need about 2.5 grams of it per meal. You need more leucine if you’re older and less active, and less leucine if you’re younger and more active. If you are following a vegetarian diet, eggs and dairy are rich in leucine. If you are exclusively plant based (or vegan), then soya proteins are a focus.

Typical servingCaloriesProtein (g)Leucine (g)
Chicken breast185362.7
Cottage cheese165282.9
Firm tofu100111
Peanut butter19070.5
Black beans220151.2

Eating protein before bed

We are constantly building muscle and constantly losing it. When we build it faster than we lose it, we can gain muscle. The time of day where muscle building is slower is at night while we sleep. As protein and strengh training are what trigger muscle building, you can understand why this might be the case. So, studies have looked at giving people protein before bed, they’ve looked at different types of protein, and if training in the evening is necessary. What they’ve found is that a big protein feed before bed (think 40 grams) will help push the body into a situation where it’s gaining more than lowing muscle. Also, research shows that this doesn’t negatively impact sleep (phew!).

Being consistent with strength training

Although protein and calories are important, nothing is more important than putting the work in. From self-reported data we know that about 1 in 3 people do something ‘strengthening’ twice weekly. Although there are many things to consider to maximise muscle building, research this year really simplified it and reminded us all to stick to the most important factors which are;

  • be consistent (choose strength stuff you like to do),
  • lift as heavy as you can safely do,
  • exhaust your muscles (can’t do anymore)
  • aim for 3 times a week.

Other factors

Like all things nutrition, context matters, it’s always complicated and nuanced, and never forget lifestyle factors. Things like gender, age, sleep, stress, disease and genetics will make a difference to the process. Women will gain strength easier than muscle and younger people gain muscle faster than older people. But, we can all do it. Also, if losing weight and trying to lose predominantly fat rather than muscle, that’s super hard to achieve if you’re not sleeping enough. (Damn those pesky kids 😉 )

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