RHM reported tough trading at its preserves and baking products business on Tuesday and said annual profit would be even more skewed to the second half than last year, hitting its shares.
The firm, which makes Mr Kipling cakes and Hovis bread, said turnover in the four months to August was about 2 percent higher versus the same period last year.
Mr Kipling cakes saw an unspecified rise in like for like sales and also gained market share, RHM said, confirming a recovery after a dive in sales in late 2005 and early 2006.
But it added that turnover and profit margins at its culinary brands business, home to Bisto gravy, Sharwood's Asian sauces and Robertson's jam, had been hit by a hot summer, as well as some retailer destocking and stiff competition.
For these reasons, as well as the impact of higher wheat prices, increased marketing spend and the timing of price increases, profit will be even more skewed to the second half than last year, RHM said in a statement ahead of its annual shareholder meeting.
At 10:05 a.m., RHM shares were down 4.4 percent at 271 1/2 pence, below the 275 pence at which they were floated in July 2005.
Panmure Gordon analysts cut their full year earnings forecast to 28 pence a share from 29.4 pence, as well as their price target on RHM shares to 270 pence from 290 pence.
The seasonality of RHM means September is a bad time to predict how the full year is going to transpire. Nevertheless, today's trading statement highlights a number of concerns, and it seems clear that little progress is likely to be made at the first half stage, they wrote in a research note.
Keith Bowman, equity analyst at Hargreaves Lansdown Stockbrokers, added: Today's statement leaves investors requiring an even greater leap of faith going forward.
RHM bakes about a third of the country's bread including the Hovis and Mother's Pride brands.
For the year as a whole, the board remains confident that RHM will deliver further progress, it said.