A calorie surplus is when you eat over your maintenance calories placing you in a ‘surplus’ of energy. This hypercaloric state has been observed to be beneficial for performance. However, if someone is in too much of a surplus it could result in the gain of fat mass. There is a fine line between being in a beneficial surplus and being in too big of a surplus, which will either improve performance and physiological benefits or hinder them.

Calorie Surplus and Performance

The role of a calorie surplus on performance isn’t fully understood and there are differing opinions across various studies that look at the lean body mass gains when someone is resistance training within a deficit and when they are not. Lean body mass has been seen to still increase when an athlete who is resistance training is in a hypocaloric state (energy deficit). However, a different study discovered that a calorie deficit decreases muscle protein synthesis which will lead to a decrease in the rate of production of lean body mass. This was observed over a 10 day moderate deficit (Approximately a 20% deficit). So if you are looking to optimally increase your lean body mass then a calorie surplus could be necessary to do so.

When it comes down to strength gains there has been evidence to suggest that a calorie surplus improves strength performance. However there is also evidence to suggest that strength gains are not significantly impacted with the use of a calorie surplus. So if you are looking to improve strength performance then a calorie surplus can be effective but again it is more important that your are training effectively and getting the appropriate stimulus.

How Much of a Surplus Should I Be In?

When looking at how much you need to be in a surplus by it is difficult to say an exact amount. This is due to there being so many factors that influence how many calories someone would need to put them in this ‘optimal’ surplus for building lean body mass, like training age, and how much energy the body uses to perform normal day to day functions. The recommended range to be in for a surplus is approximately 5-20% over your maintenance calories a day. It is then important to monitor your body composition as if you are in too much of a surplus you will also start to increase body fat mass.

Looking through various studies it is clear that a calorie surplus can have a positive impact on muscle mass and strength performance and bring about a favourable physiological adaptation. However it is also clear that in some cases eating at maintenance or sometimes even in a deficit can be seen to have similar favourable adaptations. One thing to remember that in a deficit an increase in skin fold has been observed meaning an increase in body fat. So it is important to keep track of your body composition when in a surplus to ensure fat mass gain is minimal.

Helms, et al., 2023, Aragon, et al., 2017, Slater, et al., 2019