The upmarket supermarket chain said its full details will be shared when it announces it interim results in September.
Managing director Mark Price said: “We have been achieving sales growth that has been significantly and consistently ahead of the market - indeed, we have now outperformed the market for over four years in a row, according to Kantar data.”
Total sales for the week ending 27 July were up by 4.1% which was slightly ahead of expectations and Price added: “We faced particularly tough comparatives with the equivalent week last year when we had the first sustained period of hot weather of the summer and the excitement for the Olympics had started to build.”
The chain, part of the John Lewis Partnership, also saw growth in its desserts – thanks in part to the good weather – with items like trifle and Eton mess, with sponge fingers up 277 %, meringues up 162% and strawberries up 15%.
Home baking too also received a boost, with a 13% uplift. Sugar increased by 12%, cake decorations and sprinkles up 161% and cooking chocolate up 39%.
The Heston TV advert also resulted in a 2,460% uplift in sales of his salted caramel popcorn ice cream.