The toddler years are times of change in behaviour and development. Toddlers start wanting to be independent. As well they are starting to achieve self control of thinking, behaviour and social interaction.
It is often at meal times that toddlers will show their independence. They may refuse to eat what is offered, limit the variety of what they will eat and not want to spend much of their time at the dining table.
Just like babies, toddlers know how much food they need. As long as food is offered on a regular basis, they will know how much to eat.