1. Not getting enough milk!
If your baby is not gaining enough weight, then it may be because he is not getting enough milk (breast or formula). If you're concerned about his weight, your first step would be to increase the amount of milk you offer him and if this fails to increase his weight gains, see a doctor to make sure there's no physical reason.
If your baby is breastfed, your breast milk supply may not be sufficient to meet his nutritional needs. (See our article on How to tell your baby is getting enough breast milk.) However, there are also a number of reasons for a breastfed baby to underfeed, which have nothing to do with low milk supply. If a physically well baby is not gaining sufficient weight it is wise to talk to someone who is experienced in educating mothers on breastfeeding, such as a breastfeeding counsellor or lactation consultant.
If your baby is bottle fed, you may need to offer more milk (breastmilk or formula). Take a look at our section on bottle feeding for information on how to estimate how much milk your baby needs and dealing with common bottle feeding problems. Also, check that you are making the formula correctly. If you were making it too weak your baby may not be getting the calories he needs.
Strangely, it's most often the bigger babies (who are experiencing no problems putting on enough weight) that are the most difficult to satisfy. For these thriving infants, the problem may be related to one of the following reasons.
2. Lowered breast milk supply in the evenings
It's normal that your breast milk supply can be a little lower in the evenings. This could be a reason why your little one is restless and wants to breastfeed more frequently in the evenings. If he's gaining good amounts of weight and providing your with lots of wet diapers (6 or more a day), then he's getting enough breast milk over a 24 hour period and it may help to plan your day so that you can allow for more frequent breastfeeding in the evenings.
However... if he's gaining weight well and wants to feed more frequently throughout the entire day, this could be a sign of a growth spurt.
3. Growth spurt
If your baby is formula-fed, you may find he's looking for just at little more formula at the end of each feed. An increase in the amount of formula offered at each feeding will normally resolve his restlessness.
If he's breastfed, you may need to offer more frequent breastfeeds, to stimulate an increase in your supply. Restlessness related to a growth spurt should settle within a few days and feeding patterns return to normal. If his feeding pattern does not return to normal, yet his weight gains are good, there may be other reasons for him to "appear hungry
