*This is not individualized medical guidance. Always consult a physician or other licesed healthcare professional when making changes to your diet, exercise routine, or putting this advice to action.

Why Focus on Muscle Building?

When it comes to changes in body composition, building muscle and losing fat are the names of the game. Decreasing adiposity (fat mass) and building muscle (hypertrophy) generally, aside from when taken to the extreme, result in positive health outcomes like improved glycemic control, functional capacity, blood pressure regulation, and bone density (if you want to learn more about the benefits of resistance training and hypertrophy click here). But there has been debate in the fitness community, from physique athletes to casual gym-goers, on whether achieving the two goals of building muscle and lowering fat mass (“recomposition”) can happen simultaneously.

The rate of body composition change is affected by many different factors in and out of the gym setting. Diet can alter body composition alone without exercise, but this change occurs much slower, and to a relatively lower peak when compared to changes in diet in combination with exercise (source 1, source 2). Other inputs that may affect your body composition are the type of exercise you do, your sleeping patterns, stress, and more. Probably the most important factor that plays into all of this is training experience. Research is scarce on fully trained natural bodybuilders, and although some studies have pointed to extremely high-protein diets (upwards of 2.3g/kg of bodyweight consumed per day of protein) being able to create recomposition in female physique athletes (source), this isn’t synonymous with most of the research. Most studies point to a more abundant training history creating a larger barrier to subsequent muscle gain or substantial changes in body composition (source).

So, we know recomposition may or may not be possible and is probably more achievable if large strides in optimization of training and recovery are made alongside the common dietary interventions associated with fat loss and muscle gain. But if there’s no room for strides to be made in the optimization of training and recovery, or if someone isn’t willing or able to take on the mentally tedious and draining challenge of optimizing every detail of their training, nutrition, and other modifiable behaviors, there could be a simpler solution. This solution could allow for improvements in muscularity to be made in someone who is more advanced, with more reliability, while reducing the meticulousness of recomposition.

What is a Muscle Growth Phase?

To generalize this concept, I’m going to define it as the pursuit of one of these goals at a time, specifically muscle growth. I’m sure most of the people reading this have heard of “bulking” and “cutting” cycles. I am going to refrain from this terminology to broaden the applicability of this information to those looking to create sustainable increases in muscle mass, without the need to have a subsequent removal of fat mass. Except for in the context of bodybuilding, this is a much more likely, safe, and realistic goal for the moderately-trained, non-competitive individual. Weight cycling can possibly be more harmful than a steady weight change or the maintenance of a weight (source). This doesn’t mean this info doesn’t apply to competitors, but whenever this information is applied, it should always be done in the context of the individual and by a physician or other qualified professional.

Like most of my blog posts, I am going to be sharing my experience and outlook on these basics of muscle-building phases in the context of my goals in bodybuilding. This doesn’t mean how I am using them transfers directly to how you can or should implement these interventions, but hopefully provides an example of how they could be implemented, for ease of understanding.

Energy Intake

Before we jump into calories or protein, it’s important to understand the definition of what the goal for this phase is. To achieve recomposition, the goal is typically to maintain bodyweight and alter the fat-free mass to fat mass ratio, with little to no changes in weight. However, if someone were to solely build muscle, with no increase in fat mass, this would increase weight while still improving the muscle:fat ratio. This ratio, represented as body fat percentage, may be a more important biomarker for health than weight, and prevent the misdiagnosis of obesity or overweightness, especially in athletic or trained populations (source). This is why avoidance of gaining weight is something that can work against you when trying to achieve the positive health outcomes associated with muscle growth.

If we want to grow and synthesize tissue, we need to fuel anabolism. You can’t build something from nothing, so you need to provide your body with the energy it needs to grow through a caloric surplus. This means consuming more energy in the form of calories through food and beverages than you expend through daily living, exercise, and other facets of metabolism.

So how much of a surplus should we strive for?

The current recommendation is 350-500kcal/day.

This has been the most popular prescription to avoid unnecessary gains of fat mass by athletic nutritionists since the publishing of this paper. In this review, Slaters and colleagues dive deep into the energy and macronutrient considerations that go into maximizing muscle gain from resistance training. 500kcal roughly equates to 1lb of weight gain per week, but again this is a ballpark estimation and can vary depending on the individual. There are also plenty of factors that may cause even more of a necessary surplus to optimize muscle growth along, displayed in figure 1 below.

Figure 1

An overview of factors contributing to the energy cost of skeletal muscle hypertrophy.
Sourced from: Slater GJ, Dieter BP, Marsh DJ, Helms ER, Shaw G, Iraki J. Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training. Front Nutr. 2019 Aug 20;6:131. doi: 10.3389/fnut.2019.00131. PMID: 31482093; PMCID: PMC6710320.

Excess Adiposity and Obesity as a Starting Point

What if your body fat percentage already puts you in the obese category? This is an important question with 30% of the American population living with obesity in 2000 and the number continuing to grow (source 1, source 2). Although the research is limited from what I have encountered, it is believed that excess adiposity could have a resistant effect on whole-body anabolism (growth). This includes muscle protein synthesis (the driver of hypertrophy) (source). Therefore, it may be beneficial for the individual to pursue fat-loss as an initial goal to resensitize their muscle-building potential before seeking muscle gain. This should be done while increasing their protein intake to prevent the loss of fat-free mass. Some even theorize that excess body fat could fuel muscle growth in a moderate deficit, given the body’s excess storages of energy, but this has yet to be backed by evidence. This could change if someone is dealing with sarcopenic obesity, which is the loss of lean mass and an elevated body fat percentage without a substantial increase in overall body weight. Avoiding further loss of muscle then becomes a main priority to prevent further increases in frailty. However, these populations can see substantial benefits even within a caloric deficit because of their sensitivity to the training stimulus (source).

An important note: creating a caloric surplus doesn’t mean you have to count your calories, you can focus on food choices, eating frequency, or other less burdensome ways of modifying eating behavior.

Protein

Now that we have established how to navigate thinking about calories in this phase, let’s talk about protein. Protein is easily the most propagated macronutrient in fitness and commonly denoted as the building blocks of muscle, protein is crucial to these muscle-building phases.

The reason protein is essential for muscle growth in simple terms is it’s the only macronutrient that contains nitrogen, which is an element found in skeletal muscle. Therefore, no nitrogen = no muscle.

So we need protein, but how much? We can look at an excerpt from my eBook Embrak: A Guide to Starting and Succeeding at Resistance Training for some answers:

“For those looking to jump right into serious training or muscle building, 1.7-2.2g/kg of bodyweight (0.8-1.0g/lb) is a suitable range. More protein doesn’t always mean more growth or strength gains. Around 1.7g/kg of bodyweight or 0.8g/lb of bodyweight, the benefits from more protein intake start to flatten out for most [source 1, source 2].”

This is a wide range and most like the simple numbers. But like calories, optimal protein consumption is based on individual context. One misconception I heard plenty of times throughout my years as a trainer is that because you are building muscle, you need to consume more protein than if you are in a fat-loss phase. When in a caloric deficit, a higher consumption of protein is needed to counteract the increase in protein degradation, whereas in a caloric surplus the utilization of amino acids (protein) for gluconeogenesis (energy production) is lower, so less dietary protein is needed to create a net positive protein balance (source). This is illustrated in figure 2 below, which shows hypothetical protein ranges depending on the level of caloric restriction, this points to a caloric surplus having a relative protein-sparing effect.

Figure 2

Hypothetical illustration of protein requirements to spare lean mass increasing with greater energy deficits. A rightward shift of the curve (dashed line) indicates lower protein requirements. Similarly, a leftward shift of the curve (dotted line), indicates greater protein requirements. The plateau in the lines demonstrates that, with decreasing energy intake, increased protein intake becomes less effective to spare lean mass.
Sourced From: International Journal of Sport Nutrition and Exercise Metabolism 28, 2; 10.1123/ijsnem.2017-0273

So, in the case of muscle growth in a caloric surplus, 1.2-1.7g/kg of bodyweight, as recommended by the American college of sport medicine, seems like a great target to stive for. With most of the benefits plateauing after passing the 1.7g/kg of bodyweight intake.

Tips for Achieving This Increase

When increasing caloric and protein intake in the pursuit of muscle growth, many struggle with maintaining the caloric surplus due to the high-satiety index of protein (source). In one of the studies previously mentioned about caloric intake, a method suggested that may improve the ability to achieve this increase in calories and protein is by altering the caloric density of meals. The primary method of achieving this is by increasing dietary fat intake, which is calorically denser than protein (9kcal/g and 4kcal/g, respectively). There are also few articles pointing to specific fat sources having a more positive impact on muscle growth than others, but that is a topic for another day (source).

Another method that could be used to achieve this intake is opting for liquid-based sources, which have a lower impact on satiety when compared to their solid food counter parts (source). However, this depends on much more than the state of the food, including the nutrient profile and more.

I hope this helps the folks that are interested in the more advanced aspects of nutrition and muscle growth optimization navigate some of the current research on the topic and gives you some directions to continue your growth and learning. Always feel free to reach out to me on instagram @aidanjmetcalfe for questions.

Optimizing Muscle Growth - The Current Research on Energy and Protein