Sainsbury's is helping lift the food retail sector higher after saying today a record Christmas performance completed a strong third quarter in which like-for-like sales, excluding fuel, rose by 3.7%.Like-for-like sales, including fuel, rose by 3.8% in the 13 weeks to 2 January, while like-for-like sales excluding fuel and VAT were up by 4.2%. Total sales rose 6.2%, or 6.3% excluding fuel.Peer Morrisons is also posting good gains. Data from the market research firm Nielsen today showed John Lewis leading the way in sales in the four weeks to December 26, with Morrisons the next best performer. In other retail areas, JD Sports is going well after the sportswear fashion retailer said it expects full-year profit before tax and exceptional items to significantly exceed current market forecasts.But the general retail sector is lower again, having fallen for the past two days in the wake of a cautious outlook on 2010 from Marks & Spencer and Next. JD Sports rivals JJB Sports and Sports Direct are among the fallers, with M&S and Next continuing their declines.Top performing sectors so far todayForestry & Paper 3,906.77 +1.48%Construction & Materials 3,570.28 +1.29%Household Goods 6,471.03 +1.19%Food & Drug Retailers 4,706.82 +1.17%Tobacco 25,043.63 +1.00%Bottom performing sectors so far todayMobile Telecommunications 3,214.03 -2.38%Life Insurance 3,940.54 -1.45%Electricity 6,659.19 -1.39%General Retailers 1,718.70 -1.34%Gas, Water & Multiutilities 4,090.80 -1.17%