The UK's largest bakery chain said like-for-like sales - which excludes new store openings - for its third quarter ending 2 October rose 0.2%.
Greggs said its breakfast bacon roll was now its best-selling sandwich.
It is now adding more breakfast products, including croissants and pains au chocolat.
The 0.2% rise in Greggs' sales for the third quarter was down from the 0.7% growth seen in the first half of its financial year.
Greggs chief executive Ken McMeikan said: "As we expected, the trading environment has been tough and is likely to remain so, with consumer spending continuing to be constrained and inflationary pressures building for next year.
"We anticipate that like-for-like sales in the final quarter will be broadly flat and therefore marginally positive over the year as a whole."
He added that the company was keeping a "very tight focus" on costs.
Greggs currently operates 1,451 shops. It said that its expansion programme was on track, having opened a net 32 new shops in the year to date.

The first minister has been reflecting on Scottish government proposals for a fresh ballot on the issue in the wake of the general election result.
It saw the SNP lose 21 seats at Westminster after the party's share of the vote fell from 50% to 37%.
But the party's 35 seats meant it remained the largest in Scotland.
The first minister called in March for a second independence referendum to be held in the autumn of next year or spring of 2019, once the results of the Brexit deal are known.
She has insisted a vote was needed to give Scots an alternative to a "hard Brexit" after nearly two-thirds of voters in Scotland backed the UK remaining in the EU.
But she has faced calls from opposition parties to ditch her plans - while some figures from her own party have called on her timetable to be "parked".
Ms Sturgeon discussed a referendum when her cabinet team met in Edinburgh on Tuesday morning.
Her spokesman said afterwards: "There was a discussion led by the first minister on an independence referendum and related issues.
"That forms part of the process she laid out after the election and she will continue to consult with government and party colleagues, and will lay out her views on the way forward in due course."
When asked if this would be before Holyrood breaks up for the summer recess at the close of business on Thursday of next week, he stated: "I think it is likely before then."
The spokesman added there was not "an exact timetable" for when any announcement would be made.
In the immediate aftermath of the general election, Ms Sturgeon conceded her plans for a second independence referendum were "undoubtedly" a factor in the results.
She said at the time: 'We will reflect on these results, we will listen to voters and we will consider very carefully the best way forward for Scotland, a way forward that is in the interests of all of Scotland."
Scottish Secretary David Mundell said at the weekend that he can see "no circumstances" under which an independence referendum could be held before the Holyrood elections in 2021.
Responding the comments by Ms Sturgeon's spokesman, Scottish Conservative deputy leader Jackson Carlaw said: "It's welcome that Nicola Sturgeon will set out her thinking in the next couple of weeks.
"She now has to tell Scots what they want and need to hear - that plans for a second referendum on independence are unequivocally off the table."
Labour and the Liberal Democrats also called on Ms Sturgeon to shelve her plans - arguing that another referendum was not wanted by most Scottish voters.
And Scottish Liberal Democrat leader Will Rennie said: "After a clear message from the electorate a few weeks ago the first minister must take independence off the table or be seen to be ignoring the will of the people of Scotland."

The Create Your Space programme will allow groups to apply for grants to make changes to their local areas or conserve existing sites.
The money comes from the Big Lottery Fund and dormant accounts' funding from bank and building societies.
Applicants will be able to seek grants from between £500,000 and £2m for a seven-year project.
The total grants available come to £8.8m.
The council areas are Caerphilly, Conwy, Flintshire, Anglesey, Newport, Monmouthshire, Rhondda Cynon Taff, Vale of Glamorgan and Wrexham.
Strong demand for its breakfast range has helped Greggs report a small rise in sales, despite "an increasingly challenging trading environment".
[NEXT_CONCEPT]
Nicola Sturgeon is "likely" to make a statement on her independence referendum plans by the end of next week, her spokesman has said.
[NEXT_CONCEPT]
Nine councils in Wales are to share nearly £9m to improve natural environments used by local communities.