It’s important to remember that since everybody is different, these estimates are just that. How the numbers work out for each person will definitely vary. So many factors—like genetics, hormones, sleep, and diet—can change the rate at which our bodies burn calories. And some people may have a harder time than others when it comes losing fat or gaining muscle—again, there are so many factors at play and our body chemistries are all different. Strength training is important for many, many, many other reasons (more on that later), but if you’re looking to increase your metabolism, it’s important to have realistic expectations and know that strength training can make a difference, but probably won’t drastically affect how many calories you burn from one day to the next.
If you’re not lifting super-heavy weights, doing high-intensity workouts, or eating a mainly vegan or vegetarian diet, your body probably makes as much creatine as it needs. “Creatine is naturally found in animal-based products,” says Bates, “so your body can make plenty of creatine as long as you have a balanced diet that includes animal-based products.” Protein sources like beef, chicken, pork, and fish help your body produce the creatine it needs — it varies depending on the source, but, in general, a 3-ounce serving of meat will have about 0.4 grams (g) of creatine, Bates says. (6)
The biggest mistake among young would-be bodybuilders is overdoing it, followed by not learning the proper techniques. Take those breaks and follow the correct form, or you'll give your body stress and injuries instead of muscle. Also make sure you're getting a large but balanced diet. Teens going through growth spurts need lots of food, especially when they're working out.
Using too much weight, too soon; always start lower than your expected ability and work your way up that first workout. If your form suffers, you are swinging the weight, or using momentum, this indicates you may be using too much weight. Greater momentum increases the potential for injury and reduces the effectiveness to the muscle group being targeted.