UK retail sales were subdued in July, despite better weather and the start of the Olympics towards the end of the month.
These factors helped the sale of food and drink, the figures from the British Retail Consortium indicated.
Overall, sales rose just 0.1% in July compared with a year earlier on a like-for-like basis, which strips out the effect of newly opened shops.
This reflected the continued squeeze on household incomes, the BRC said.
Online retail sales rose 15.6% in July compared with the same time last year. Cooler weather helped drive online traffic at the beginning of the month as consumers spent more time at home, the consortium said.
Some retailers had benefited from longer opening hours brought in for the Games, the BRC said.
However, the sporting events only started at the end of July, so August's figures are likely to give a better indication of the impact on spending habits.
"Let's hope that Team GB keeps on increasing its medal tally, bringing a feel-good factor that helps consumer confidence," said Stephen Robertson, director general of the BRC.
There have been concerns that people have been put off from shopping in central London because of warnings of overcrowding due to the Olympics.
The number of people going to shops on Friday 27 July, ahead of the opening ceremony, was 10.4% lower than a year ago, said research group Experian.
The group, which measures the numbers of people visiting shops, but not how much they spend, said customer footfall levels were 11.7% down on Saturday, the first day of the Olympics competition.
More recent Experian figures show that the effect of the Games had lessened since then.
Between Wednesday 1 and Saturday 4 August, as Team GB's medal tally rose dramatically, the number of visitors to central London shops was down by between 2.1% and 4.5% compared with the same day a year earlier.
On Sunday 5 August, when the women's marathon was being held in the centre of the city, footfall was up 4.5%.
"Clear messages that the city is dealing effectively with the Olympic crowds and relaxed Sunday trading laws have together made an impact and certain retailers and particular sites witnessed significant increase in shopper numbers," said Experian in a statement.