For children, these reactions should not be in balance. In a child, the anabolic reactions have to be greater than the catabolic. Boys start their growth spurt after girls. That’s why when they are in 7th or 8th grade, the girls are still taller than the boys. The boys change a couple years after the girls. Guys may gain 2-3 inches in that growth spurt between 14-17 years of age. During that growing period they will eat up all the food in your refrigerator. They are growing like crazy during that time. But what happens to both boys and girls at 18-19 is that if they keep eating the same way, they won’t grow taller anymore but only wider. This is the phenomena everybody notices.
There are many signals that control catabolism. Most of the known signals are hormones and the molecules involved in metabolism itself. Endocrinologists have traditionally classified many of the hormones as anabolic or catabolic, depending on which part of metabolism they stimulate. The so-called classic catabolic hormones known since the early 20th century are cortisol , glucagon , and adrenaline (and other catecholamines ). In recent decades, many more hormones with at least some catabolic effects have been discovered, including cytokines , orexin (also known as hypocretin ), and melatonin . [ citation needed ]