Feeding only milk & baby food

So pedi said to start cereal... well we tried rice, constipated LO & trued oatmeal made him too gassy..

So as his mom... I thought who needs that junk.. just did baby veggies... and hes been good! :) loves green beans!

BUT im not sure how much he should be getting. Right now hes eatin 3x/ day, 1/3 of jar each meal= jar a day.

Although without cereal. I think it may not be enough. I think he could eat more. But I dont want to overfeed him.

Any thoughts or suggestions?