I had five children all of whom are grown.
I breast fed all of them back when few women did.
I gave them rice cereal at 6 weeks and they slept through the night from then on. They had no digestive problems and gained weight and were very healthy.
I hear about mothers who did not give their children solid food until they were much older being up every night for months with hungry children.
Soon after they started on rice cereal I gave them other canned baby food.
I know that what I did is now considered very bad but it seems to me that I had less trouble with the five of them than most mothers nowadays have with one.