CT has an analogy for this…
Quote: "I like to use a construction worker analogy to explain this. Imagine that your muscles are like a house you’re trying to build. The bricks used to build the house represent the amino acids (from the ingestion of protein) while the money you’re paying the workers (so that they’ll do the work) represents the carbs and fat you eat.
Finally, the workers represent the factors involved in the protein synthesis process (Testosterone mainly) and the truck bringing the bricks to the workers represent insulin (which plays a capital role in transporting the nutrients to the muscle cells).
If you don’t give the workers enough bricks (protein) they won’t be able to build the house as fast as they could. So in that regard, an insufficient protein intake will slow down muscle growth.
Similarly, if you don’t pay your workers enough (low carbs or fat intake) they won’t be as motivated to work hard. As a result, the house won’t be built very rapidly. In fact, if you really cut the workers’ pay, they might even get mad, go on strike, and start demolishing the house (catabolism due to an excessively low caloric intake). So in that regard, not consuming enough protein or calories to support muscle growth will lead to a slower rate of gains.
Now, what happens if you start to send more bricks (increase protein intake) to the workers? Well, they’ll be able to build the house more rapidly because they aren’t lacking in raw material. However, at some point, sending more and more bricks won’t lead to a faster rate of construction because the workers can only perform so much work in any given amount of time. For example, if your crew can add 1000 bricks per day to the walls, giving them 2000 bricks per day will be useless: it exceeds their work capacity. So the excess bricks will go to waste (literally).
In the same regard, if you increase your workers’ salary (increase caloric intake) chances are their motivation will also increase and as a result they’ll build the house faster. However, just like with bricks, there comes a point where increasing the workers’ salary won’t have any effect on the house-building rate: the workers will reach their physical limit. Once this limit is reached you can increase their salary all you want; they won’t be able to add bricks to the house any faster.
What I’m trying to say is you can’t bully your body into building muscle by force-feeding it. Adding nutrients and calories will have a positive effect on muscle growth until you reach your saturation point. After that, any additional calories will be stored as body fat.
So while it’s true the more you eat the bigger you’ll get, the additional weight will be in the form of fat, not muscle tissue."