Depends on your diet and on your baby.
If you had a healthy pregnancy diet then no, but you should add a little more...
There are two sets of figures for the additional calorie intake required after three months.
Group 1 mothers are those whose breast milk no longer supplies all or most of their baby's food after the first three months.
Group 2 mothers are those who supply all or nearly all their baby's energy and nutrient needs for six months or more.
3-6 months:
Group 1 - 480 calories
Group 2 - 570 calories
More than 6 months:
Group 1 - 240 calories
Group 2 - 550 calories
If your baby is fussy, colicy or showing signs of an allergic reaction then you can try an elimination diet too see if any of the foods you are eating are causing the problems.
With my mother, sister and sister-in-law, cutting dairy from their diet helped their baby from getting stomach trouble.