The importance of a good healthy diet can not be underestimated for your growing child. A good diet leads to his active development. However, another equally important element for his growth is - Sleep!
What you need to know
You still need to supervise his sleeping patterns. Most kids who do not get proper sleep develop poor concentration and attention deficiency. According to research, children aged 4-5 must sleep at least for 11 hours every night. Short naps after coming back from school are also fine so that the child can rest his body.
To avoid cranky behaviour make sure he sleeps at an early hour and wakes up within a time frame of 11-13 hours. Do not let the kid sleep too much either. This could backfire because at times this can might grow him lazy. To maintain a proper sleep time make sure the kid is engaged in sports or other physical activities. Make sure the kid watches TV only for limited hours. Enforce strict rules if the child is adamant.