I never bothered with set portion sizes. I just got used to how much she was devouring and whether she was wanting seconds and was led by her. At 1 yr my LO was eating more than she does now at 5yrs (can anyone say huge growth spurt!), like adult portion of shepherds pie and peas, then a banana, then two yoghurts, then 5mini rice cakes, then a pear, then a snack bar. I think all kids are different though and as long as they try a varied diet you can trust they won't starve themselves if you follow their lead.