V.C.
Just like adults -- or even moreso -- babies take spells of less or more appetite, and with growth 'spurts' --and between, they need less or more ingestion. It's natural!
Please look around at all the overweight people in America and realize that encouraging anyone to 'eat more' (unless they're truly sick or so depressed that they don't want to eat anything) is counter-productive. Your child WILL EAT when s/he is hungry!
Diet is not an emotional issue. It is a sustenance issue, but it can quickly turn into a battle of wills and a control issue if treated with too much concern.
As long as any baby or child eats, drinks, pees, poops, has energy, rests well and seems healthy & happy, DON'T SWEAT IT!