Hi, there,
At 4 months babies are usually too young to eat - that's why it's recommeded by all reputable authorities that babies start solids at 6mnths. Unfortunately there is a lot of conflicting advice around this and it is very confusing for mums. If he's just not enhoying it, give yourselves both a rest for a month and try again later when he's a little more able to cope with solids. In regards to solids we know that when solids are introduced under 6 mnths they tend to displace breastmilk from the diet. Most of the first solids we give babies are very low in calories (the sort of foods we'd eat if we were on a diet) So they are not usually going to help a baby grow - at that age they need milk. Tell us some more about his weightgains. Some mums, and some health profesionals don't realise that the charts we use are charts of normal baby growth - if your baby appears on the chart it is in the "normal' range. 1/2 of babies will be below the 50th percentile and 1/2 will be below - it's all normal. There are several factors that affect baby's growth, including genetics - so tell us a little more of what is happening with you.