I am four weeks pregnant and would like to know what foods are best for me to eat for my baby to grow

You need to take your prenatal vitamins
And omega fatty acid is really good for babies even after they are born.
Try avoiding sugar, artificial sweeteners and caffeine

Talk with your OB.

Fruits and vegetables and your prenatal vitamins specially folic acid for your baby's brain which is very important during the first trimester. :) goodluck and congratulations