Children’s obesity is the volume and quantity of fat cells increase at the same time, adult obesity is mainly the volume of fat cells increase, so if children’s obesity is not effectively controlled, the probability of adult obesity may increase and difficult to control. The key period to prevent children’s obesity is as follows: 1, before and after the birth of newborn: should keep the baby’s weight in the moderate range, too big or too small weight are not beneficial to health; 2, breastfeeding period: within 1 year old baby milk fat should be controlled within a certain range, excessive milk fat should be noted; 3, adolescence: once obese may induce adult obesity, difficult to control.