Calories are a measure of the energy present within foods. Only three types of molecules contain calories: carbohydrates, proteins and fats. These molecules also have various functional and structural uses in the body. For example, cells use proteins to form the basic machinery that allows the muscle fibers to contract and control movement. Along with strength training, proper calorie consumption is an important component of bulking up.
Average Daily Calorie Intake
Daily calorie requirements depend a number of factors such as age, activity level and genetics, so each person may burn energy at a slightly different rate. However, it is also possible to generalize calorie expenditure across a broad spectrum of people. According to exercise physiologists William McArdle, Frank Katch and Victor Katch, active males between the ages of 25 and 50 expend an average of 2,900 calories a day; active females of a similar age expend about 2,300. Therefore, you will have to eat a similar number of calories to fuel your daily activities and maintain a proper energy equilibrium.
Calorie Intake to Build Muscles
According to experts from Columbia University, research has shown that you should consume an additional 2,270 to 3,630 calories per week to build as much as a single pound of muscle during that time span. This equals about 500 additional calories per day. A typical 180-lb. male needing about 2,700 calories per day would therefore require at least 3,200 calories. Furthermore, an hour of intense weightlifting burns 500 calories. Added up, this same person may consume as much as 3,700 calories on lifting days just to properly bulk up.
Just as important as the number of calories is the composition of calories. Protein is needed to provide the amino acids upon which muscle fibers are repaired and built. Every day, a topflight athlete or bodybuilder needs approximately 0.68 to 0.9 g of protein per pound of body weight. Most people who want to build some muscle will probably settle for less than the high end but more than the 0.36 g recommended for the average person. Without the proper consumption of protein, the muscles may not grow at a rate that is in accord with the actual amount of growth facilitated by strength training sessions.
Carbohydrates are used to fuel muscle growth. They are stored in the muscles in a form known as glycogen. If the muscles get low on glycogen, you may begin to feel weak, tired and fatigued, affecting the integrity of your workouts and the rate of muscle synthesis. For this reason, an athlete or bodybuilder should consume 3 to 4.5 g of carbohydrates per pound of body weight. However, the high end is only for ultra-endurance athletes and unnecessary for building muscles.