The grocer, which is the UK's third biggest, also revealed that its total sales for the sixteen weeks to October 7 had risen 8 per cent excluding petrol.
Sainsbury's chief executive Justin King said that the strong figures were due to 'spells of good weather', an ongoing store opening and refurbishment programme and the introduction of 250 new products.
However, King warned that the market would remain highly competitive and that the retailer faced increasingly tough comparatives for the second half of the year.
He added that there would be a 'significant step up in our energy costs of about£55 million in the second half of the year'.
Analyst Goldman Sachs said that the update was 'strong', but added that the statement's 'cautious tone' highlighted the business's 'struggle' to recover operating margins.
Sainsbury's will unveil its interim results for the 28 weeks to October 7 on November 15.