The cost of fruit and vegetables has risen the most, up 16 per cent since January, according to retail analysts Verdict.
The price of branded goods increased more than supermarkets' own brand ranges, while the cheapest ranges saw little change, the report said.
Verdict said retailers were absorbing some of the price rises.
Neil Saunders, consulting director of Verdict, said: "Although the price of goods is rising, the UK's grocers are helping to mitigate price rises."
Consumers spent 13p in every £1 on food, meaning a 5.8 per cent increase in prices since the start of the year was "particularly painful".
"Such rises, combined with hikes across other areas of household expenditure, are squeezing the amount consumers have to spend on things like leisure activities and on other retail goods, " the report said.
"For many people it also means that inflation feels far higher than the Government's official rate."
It forecasted strong food price inflation throughout this year and in 2009.
The research was based on a "typical basket" of 100 grocery items.