I’m really not sure where this idea comes from, I guess partly from the idea that if adults stop weight training, then their muscle will ‘turn’ to fat, which of course is just not possible, as muscle and fat are created differently.
Within 6-12 months of resistance training, children can expect to be leaner, stronger and of normal weight for their age. These exercises increase lean muscle mass and boost metabolism, thereby decreasing fat. Coupled with a diet of "real food", children achieve normal weight and their confidence subsequently lifted immensely. What really makes kids fat is a poor diet and not enough exercise.
Here’s how we helped one boy:
“Thirteen-year old Arthur came to us for regular classes two years ago, suffering from knee pain. He was also overweight despite regular hour-long swimming sessions. Nathan's tailored exercises helped him strengthen his lower limbs to eliminate his knee pain. His strength and stamina also improved, his nutritional requirements and diet adjusted, and as a result, he slimmed down to a normal weight.”