I dont think we can control much on the weight. Just trying our best to eat for 1 person healthily.I don't think there is an "ideal weight" for babies right? If gynae don't voice concerns usually it's ok. Doesn't matter what weight so long bb is healthy. Worrying is bad for baby too.
Basic staple diet is milk, fish, eggs, vege, meat. I was actually advised that on top of calcium supplements if can drink milk better cos bb & mummy both need calcium for strong bones. The gynae's nurse told me 4 cups milk but I think she's crazy to even suggest 4 cups especially @ final trimester with bad heartburn (+ i don't like that particular nurse)...
My bb suddenly put on 700g between 34-36th week.... So yes may have sudden growth spurt. She's aldy 3.35kg now at 38wks. I don't have much appetite just try to eat 3 proper meals a day... My previous 2 pregnancies bb only 3kg at 40wks so everyone also blur dunno why this little girl is so "fat"!!
As for ideal weight, of coz we shouldnt be over concern as long as baby is healthy.
However here are some reading on fetal weight. Medscape: Medscape Access