The analyst said that this was a faster increase than that at UK supermarkets, which grew at only 0.6%.
Nielsen concluded that the shift towards convenience stores came as workers return to offices, children are back in school and consumers are shopping little and often.
Even so, the £9.8bn shoppers spent at the major supermarkets in the four weeks to 11 September represented a £526m increase on the same period pre-pandemic, in 2019.
Mike Watkins, NielsenIQ’s UK head of retailer and business insight, said: “UK shopping habits are shifting once again, this time towards convenience channels as Brits return to more impulsive shopping behaviours that correspond with a return to pre-pandemic lifestyles. The warm weather in early September also helped.
“However, there remain some clouds on the horizon as rising energy costs and inflation could hit disposable incomes, whilst availability concerns could present challenges.
“However, grocers can still expect to look forward to a short term boost as some of the incremental spend has not yet returned to the hospitality channels, and shoppers are likely to plan in advance if household budgets are more constrained.”