Image source, Getty Images
By Tom Espiner
Business reporter, BBC News
Some suppliers have raised prices by more than their costs went up over the past two years, according to the UK's competition watchdog.
This has helped push up food prices, the Competition & Markets Authority (CMA) said.
The findings are part of an analysis of pricing in 10 categories, including baby formula, milk and baked beans.
High food price inflation has mainly been driven by rising energy and fertiliser costs, the CMA said.
But about three quarters of branded suppliers have also been making more profit on individual products.
As a result shoppers have increasingly turned to own-label products, meaning branded products have lost market share.
But in the case of baby formula there are not many alternatives, and prices have risen by a quarter over the past two years.
New parents could make significant savings of £500 in the first year of a baby's life on baby formula by shopping around, the CMA added.
Cheaper formula still needs to follow rules on providing the nutrients babies need, it said.
But the market is dominated by two big players, and there is little evidence of parents switching to cheaper alternatives.
"We're concerned that parents may not always have the right information to make informed choices and that suppliers may not have strong incentives to offer infant formula at competitive prices," said Sarah Cardell, chief executive of the CMA.
She added that the pace of food price rises "has put huge strain on household budgets".
The watchdog will probe the baby formula market further, and will also look at supermarket loyalty card schemes.
Some supermarkets have only been making cheaper prices available to customers on loyalty card schemes, and the watchdog will look at this practice in 2024.