Why is calorie surplus needed for muscle gain? Is this essential? Isn’t eating a balanced CH / protein ratio enough?
Thanks in advance!
First off, it actually is possible for overweight people to build muscle while on a low-calorie, high-protein diet:
>[T]here is clear evidence of marked skeletal muscle hypertrophy in response to a novel resistance training stimulus in otherwise healthy, overweight individuals in conjunction with a hypoenergetic, higher protein meal plan.
However, being in an energy surplus state does make an independent contribution to the level of muscle growth someone’s body will undertake. This anabolic trigger occurs even in the absence of resistance training:
>[T]here is clear evidence of a whole body anabolic response to overfeeding, even in the absence of a resistance training stimulus in sedentary populations.
The reason why is not described as fully clear down to a mechanistic level in that article, but may have some cause such as: “A person who is overfed puts more energy into metabolic processes.”
What is known is that calorie restriction turns off anabolic processes by altering your natural anabolic hormone levels:
>It is now well-established that energy restriction can significantly influence anabolic hormones in exercising individuals, potentially impairing their ability to gain and maintain LBM [lean body mass].
The reverse does not appear to be true, though, calorie surplus doesn’t seem to raise your testosterone or anything like that.
Muscle is a highly metabolic tissue and requires more calories the most other tissues just for maintenance along. Your body can only support so much muscle at any given calorie level. Increasing muscle mass causes increases in metabolism and requires more calories. Plus, more muscle tissue means bigger glycogen stores needed for physically-demanding activity.
Muscle is metabolically expensive. Biologically the body only keeps the minimum amount it needs to survive. It does this because as stated, having more muscle that serves no survival purpose costs a lot of energy.
Muscle tissue can grow without the presence of excess calories in a few scenarios (overweight, beginner, de-trained folks) however in the standard well trained folk, very unlikely and shouldn’t be relied upon.
Think about it like this:
A calorie surplus is described as eating more calories than your body requires to function. This means your maintenance calories is exactly what your body needs to spend every bit of energy and have none left.
Muscle tissue growth requires energy. This means you need energy to do so which would require you to have energy that isn’t used by the body’s regular processes.
This is (loosely) why you require being in a calorie surplus to grow muscle tissue.
EDIT: Further to the point of muscle being metabolically expensive - this is why retaining the same training volume/intensity during a calorie deficit is so important to force the need for your body to retain as much of the grown muscle tissue as possible.
The body needs extra calories to build either fat or muscle. If you are at a deficit, you’ll be destroying tissue quicker than you can build it.
With that said, beginners will see some muscle growth, albeit at a very low rate.