On a quest to find that sweet spot of calories that means you optimise muscle gains relative to fat stores? Energy needs are dynamic and adaptive – so it’s not straight forward!
Table of contents
Can you build muscle in a calorie deficit?
Research on overweight individuals shows they can be in an energy deficit, consume a high protein diet, follow a structured resistance training programme and gain lean body mass (1,2).
Research also indicates that a few days of a modest caloric deficit, results in a reduction in muscle protein synthesis (MPS) by approximately 30% (3). However this can be restored to levels at rest by a single bout of resistance exercise and further enhanced by protein ingestion.
Whilst muscle hypertrophy may be possible in an energy deficit, this will be dependent upon the individual – levels of body fat, energy availability and training levels. Also whether it is possible to build muscle in an energy deficit is not the same as whether it is optimal to maximise muscle gains.
Does eating more calories help to build muscle?
Energy is required to build muscle – the process of building, storing and maintaining muscle is energetically costly. Some individuals may have sufficient energy availability to not require a dietary surplus for muscle gain. Specifically how energy from internal body fat stores versus diet contribute to the process of muscle building is unclear.
Resistance training is the most important factor for maximising muscle gains, followed by adequate protein intake and energy to support this. A calorie surplus doesn’t mean that you will gain muscle. The proportion of muscle and fat you gain will be dependent upon a host of factors including your genes.
Research also shows that eating more calories can benefit muscle mass gains. A study showed that individuals provided a daily caloric surplus of 1000 calories over 100 days, gained 5.4 g of fat mass and 2.7 g of fat free mass, despite maintaining a relatively sedentary lifestyle (4). The study done on twins highlighted the varied response to overfeeding and the role of genetics in body composition.
The role of protein for muscle mass gains is a priority – an 8 week study where individuals were provided with varying protein intakes, all in a caloric surplus, showed that only the higher protein intake group made gains in lean body mass (3.5 kg) (5).
Importantly, short term studies (8 weeks) have shown that an energy surplus along with resistance training results in favourable gains in lean body mass (6,7).
What is the ideal calorie surplus to gain muscle?
The composition of muscle is assumed to be approximately 75% water, 20% protein and 5% fat, glycogen and thus the assumed energy stored within 1 kg of muscle may be approx. 1250 calories. Building lean muscle mass requires additional energy costs: the generation of new tissue and storing energy within muscle tissue as well as resistance exercise plus post-exercise elevation in metabolism. This may put the energy cost of building 1kg of muscle at approx. 5,250 calories – however, this is an approximation and will vary dependent upon the individual. For example, just the energy costs for resistance exercise will vary depending upon body weight and size, sex, age, fat mass, lean body mass and total exercise volume. As will the post-exercise metabolism elevation.
An energy surplus may also be required to meet the increase in lean body mass at rest and during exercise. However, this is less than presumed with a predicted 12 cals/kg of skeletal muscle mass. Given this the elevation in resting energy expenditure in response to a 1-2 kg gain of lean muscle mass is likely very small, approx 23 cals! However, depending upon the individual and their level of leanness, during overfeeding there may be an increase in organ size which also contributes greatly to resting energy expenditure, increasing the requirement of an energy surplus.
When you increase energy intake, the body tends to respond by burning off more or less energy then would be expected by a change in body mass. This is highly variable between individuals and known as adaptive thermogenesis – you can find out more about it here. Factors that contribute to this variation include genes, energy expended when you’re not exercising (non exercise thermogenesis, NEAT) and energy expended through your diet.
Research indicates that there can be a variation in up to 1000 calories for NEAT depending upon the individual in response to overfeeding. Therefore if you’re someone who burns off a high proportion of your caloric surplus, then you will have less available to be stored as fat, versus someone who does not and this will obviously impact how much muscle versus fat you gain in a calorie surplus.
For muscle mass gains, more calories isn’t necessarily better. A study where athletes were either provided with a controlled surplus of calories, or able to eat as desired, showed that whilst both groups gained similar amounts of lean body mass (1.7-2.2 kg), the controlled calorie surplus group gained 1.1 kg of fat mass, whereas the group who were able to eat as desired, ate at maintenance and did not gain fat (8).
It’s likely that there is an energy surplus threshold that is optimal for an anabolic environment to support muscle mass gains, unique to each individual.
What influences your ideal calorie surplus to gain muscle mass?
What should your calorie surplus be?
These guidelines are based on a combination of Mcdonald’s recommendations, general research and client experience, for clients with the goal of muscle gain who are either at a healthy or lean weight.
|Training experience||Gain (kg/month)||Surplus/Day (calories)|
Steps to determine your calorie intake for muscle gain:
Step 1: Determine maintenance calories
You can use a calorie calculator (use one that utilises lean body mass). Or my preferred method is to track calorie intake over two weeks, along with weekly weigh ins (times 3 times which you take an average of) to see if what you are currently eating is maintenance and then adjust accordingly.
Step 2: Select calorie range recommendations based on training experience
If you are at a lean or healthy weight, select the range of calorie surplus based on training experience. If you are overweight / have higher body fat, you do not require a calorie surplus.
Step 3: Track gains
Your method of tracking may include using body composition scales, body composition testing etc or measurements. However, a combination of weekly weigh ins, photos and recording your progress in the gym (weights and reps) can well inform your status of progress.
Step 4: Adjust accordingly
If you find that you are not making the gains that you want after a 2-4 weeks, providing you are putting the work in in the gym, have your nutrition on par (check out here)and are sleeping enough, then make a small caloric increase.
Whilst a calorie surplus is not required to build muscle: it is likely to optimise rates of muscle mass gains (for anyone who is at a healthy or lean body weight).
Whilst resistance training is the most important factor for maximising muscle gains: dietary intake (energy balance and macronutrient intake) alone can influence body composition. Combining resistance training with specific nutritional strategies is required for maximising muscle mass gains.
Body fat levels and energy availability influence whether an energy surplus is required to maximise muscle mass gains: and individuals can build muscle mass in an energy deficit. However, a surplus is likely beneficial for muscle gains if you are at a healthy/lean weight. The extent to which you can continue to gain muscle whilst being in an energy deficit is unknown – how energy from internal body fat stores versus the diet contribute to the process of muscle building is unclear. Additionally, at some point, a calorie deficit will contribute to a catabolic environment, not conducive to muscle building.
Whilst a calorie surplus is helpful for building muscle for many individuals, more is not necessarily better: it is likely that there is a certain surplus of energy, dependent upon the individual that is beneficial to maximising muscle gains. Beyond this, the calorie surplus will go to body fat stores.
If you are of a lean/healthy weight: choose a caloric surplus based on the above recommendations and measure your body composition regularly and adjust your diet accordingly every 2 weeks.
An energy surplus does not negate the need for hitting total protein intake: which is likely a highly important factor in maximising muscle gains. Hit a range of 1.6-2.4 g/kg protein/bodyweight and choose the lower end if you are overweight. If you are leaner 2.4-3 g/kg protein//bodyweight may be beneficial.
What’s your experience with calorie intake for you to gain muscle? Have you worked out your sweet spot? Would love to hear in the comments below!