A new study from the University of Iowa suggests kids who are active at age five have a better chance to stay lean even if they don’t remain as active over the next six years. Lead author Kathleen Janz calls it a "banking" effect. "That means there was something protective about their activity at age 5 that allowed them, at least in our study, to have less fat later on in childhood," Janz explained.
U-I researchers tested the body fat and activity level of 333 kids at ages 5, 8 and 11. Their findings indicate that kids who are active at age 5 end up with less fat at age 8 and 11, even when controlling for their accumulated level of activity. Janz also found that boys are more likely to experience the banking effect than girls.
She says that may be because the boys at age 5 were more active than girls. "So it might be that boys and girls are just different or it might just be that because boys were more active at age 5, they got better benefits later on at age 8 and age 11," Janz said. The researchers say further study is needed to determine if the active 5-year-olds will still develop less fat as teens and young adults.
Janz also wants to learn exactly what causes the banking effect. "We need to figure out…is it that they ended up with fewer fat cells because they’re active at age 5? Or that they have a different type of insulin/glucose relationship…or what is it in fact that changed biologically that seems to have allowed for some protection as they matured," Janz said.
Whatever the cause, Janz says the research implies that even 5-year-olds should be encouraged to be as active as possible because it appears to pay off as they grow older.