My baby also behaves this way. It's is due
to colic. After feeding try to put him up right or put him in an incline position.
If your baby is breastfed, following a nondairy diet may be worth a try, even though there's no conclusive evidence that it helps. If you're breastfeeding, talk to your doctor about cutting back on milk, cheese, and yogurt for a couple of weeks to see whether it makes a difference. (Cow's milk protein can remain in breast milk that long, so this dietary experiment takes some patience.)
If you're breastfeeding, it's also possible that your baby is sensitive to something in your diet other than dairy products. There's plenty of controversy about which foods are problematic (and the data is conflicting), but the prime suspects seem to be wheat, eggs, nuts, fruit, caffeine, and chocolate.
To see whether one of these foods is making your baby uncomfortable, avoid them all for a few days. If your baby seems better, reintroduce one food at a time, allowing a few days between reintroductions. If your baby starts fussing again after you start eating a certain food, you may have discovered the offending substance. Talk with your doctor if you notice a certain food makes your baby fussy.
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Momsy of 2 curious junior