Shares in food and coffee franchisor Retail Food Group fell 10 per cent after the company trimmed profit growth forecasts and flagged writedowns that will slice bottom-line profits by about 16 per cent.

RFG, which owns brands including Crust Gourmet Pizza and Pizza Capers, Donut King, Brumby's Bakery, Michel's Patisserie and Gloria Jeans, issued a trading update on Wednesday saying it now expected underlying net profit in 2017 to rise 15 per cent rather than its original guidance of 20 per cent.