The Anglo-Dutch group cut its full-year target for growth for its top 400 brands, such as Magnum ice cream and Hellmann's mayonnaise, from 5-6% to 4% and said second quarter growth would be 3%, in line with the first quarter.
Unilever blamed the revised outlook on a "soft performance" for its SlimFast diet brand and a slump in the travel retail market for hitting demand for its Calvin Klein fragrances.
It added that in the US, sharper-than-expected trade destocking, particularly from retailers facing financial difficulties, had exacerbated weak market conditions.
Unilever's head of investor relations, Howard Green, said: "We have given up more of the headroom in our plan than we are comfortable with at this stage of the year."
However Green added it was still on track to deliver restructuring savings of 1700m across 2003 and 2004 and savings of 1600m from its global buying programme in 2003.