My bb is 6 months old now. Should I feed him with porridge or rice cereal? Thank you!

Traditional and grand parents prefer porridge and we grew up eating porridge too. And if they are the caregivers i wouldnt fight too hard so long there is no salt. If i am the caregiver i would give cereal as first food. I have been using happy bellies cereal from iherb for all my kids. Recently i had a few sample size friso milk based cereal whcih i bgt along for my travel. My baby loves it and i like it that i no longer need to add milk to make it more wholesome as there is milk content in it already. Normally i would stirred in milk with my happy bellies cereal..and friso milk based cereal also not too sweet.