Too little exercise, too much junk food  -- most of us know these explanations for childhood obesity. But the amount of sleep your child gets may be just as important, according to a review of studies in the Archives of Disease in Childhood. Researchers found that kids who sleep less than the recommended amount at age 2 are more likely to be obese at age 7.

One reason: Fatigue alters the levels of appetite-regulating hormones, which can cause children to eat more, says Shahrad Taheri, M.D., author of the review.

To make sure your child gets all the snoozing she needs:

* Stick to regular sleep and wake-up times, even on weekends.

* Create a calming bedtime routine, like a warm bath followed by a book.

* Limit caffeinated beverages, especially before bed.

* Keep her room dark and quiet at night, which means no TV.

* Encourage her to exercise (active kids tend to sleep better)  -- but not right before heading to bed.

* Make sure she has enough downtime, since stress can lead to sleep problems.