Your child may just be a slow eater. But here is some advice even if that is the case. Consider the age of your child...still rather young. Probably in Kindergarten and they are slow eaters for the most part. Make sure that during meal times, you provide a relaxed eating environment free of distractions such as the tv. You will have to train your child to finish his/her food in a resonable amount of time..let's say 30 minutes to start because you want them to have success at first and not get discouraged. Use a timer and REALLY praise accomplishments. If the food is not finished in the designated amount of time, then take the plate away and do not offer any more food until the next meal. Practice makes perfect!!!!
Hope this helps. Have a great day!!!