Investors have lost their appetite for food producers after a good day yesterday.Hovis bread maker Premier Foods gave the sector a lift despite posting a fall in profits and saying high wheat prices will hurt the full year figures.But investors have been digesting figures from Unilever, maker of Hellmann's mayonnaise, Flora spread and much more, and are not too impressed.The company saw volume growth slow in the second quarter and expects the trading environment to remain difficult for the rest of the year.Aviva is behind a big jump in the insurance sector after it reported a better-than-expected 21% rise in its half-year profit.Aviva posted an IFRS operating profit of £1.27bn in the first six months of the year, up from £1.05bn a year ago and higher than forecasts of £1.15bn.The group also grew sales for the third consecutive quarter and improved the group's margin.Top performing sectors so far todayAutomobiles & Parts 3,518.79 +3.79%Life Insurance 3,837.94 +2.65%Industrial Metals & Mining 6,100.97 +2.05%Health Care Equipment & Services 3,190.94 +1.99%Technology Hardware & Equipment 512.04 +1.73%Bottom performing sectors so far todayFood Producers & Processors 4,680.42 -3.54%Aerospace and Defence 3,110.67 -1.67%Beverages 8,582.89 -1.21%Tobacco 25,904.24 -0.99%Household Goods & Home Construction 5,943.97 -0.60%