Although the EY Item Club think tank predicts the economy will grow 1.9% this year, it expects that performance to fizzle out as inflation rises.
The economy's stability since June's Brexit vote was "deceptive", EY said.
Meanwhile, a senior Bank of England official told the BBC that inflation may surpass its 2% target.
In an interview to be broadcast on Monday, the Bank's deputy governor Ben Broadbent told Radio 5 live that sterling's weakness would fuel inflation, but that controlling prices with tighter monetary policy could hit growth and jobs.
The dilemma facing policymakers was underlined in the Item Club report.
It expects inflation to jump to 2.6% next year before easing back to 1.8% in 2018. That will cause growth in consumer spending to slow from an expected 2.5% this year to 0.5% in 2017 and 0.9% the year after, the report said.
Business investment is also forecast to fall due to uncertainty surrounding Britain's future trading relationship with the EU, dropping 1.5% this year and more than 2% in 2017.
EY predicts that the impact of weaker consumer spending and falling investment will cause UK GDP growth to drop sharply to 0.8% next year, before expanding to 1.4% in 2018.
Peter Spencer, chief economic advisor to the EY Item Club, said: "So far it might look like the economy is taking Brexit in its stride, but this picture is deceptive.
"Sterling's shaky performance this month provides a timely reminder that challenges lie ahead. As inflation returns over the winter it will squeeze household incomes and spending.
"The pressure on consumers and the cautious approach to spending by businesses mean that the UK is facing a period of relatively low growth," he said.
The report said that exporters will benefit from the depreciation of sterling, which last week tumbled against a basket of currencies. Exports will increase by 4.5% in 2017 and 5.6% in 2018, EY forecast.
But Mr Spencer did not expect this to be enough to offset a wider slowdown.
"With activity in the domestic market flat, GDP growth will become heavily dependent upon exports next year," he said.
"But once the UK has left the EU certain sectors, such as aerospace, automotive, and chemicals that trade extensively with the EU will be a lot more vulnerable and may need to be supported by subsidies and more robust industrial policies," he said.
Some of the economic challenges were spelled out in Mr Broadbent's BBC interview with 5 live's Sean Farrington.
The deputy governor, echoing remark's by the Bank's governor Mark Carney last week, said that letting inflation run ahead of the 2% target might ensure the economy does not suffer.
Tighter monetary policy to meet the target could lead to "undesirable consequences" such as lower growth and higher unemployment, he said. It's a "trade off", he added.

Investigators from the League Against Cruel Sports said they saw no gunmen and heard no shots when they filmed the Jedforest Hunt in February 2016.
However, Malcolm Henderson told a court he had been there with a shotgun.
John Clive Richardson, 66, and his son Johnny Riley, 24, both deny deliberately hunting a fox with dogs.
Mr Henderson, who has worked with the hunt for the past two years, said he had been at the site near Jedburgh on the day in question.
He told Jedburgh Sheriff Court he was present when a fox was flushed from cover and pursued by hounds towards his gun which the law permits.
He told the trial: "I was there.
"I was down in the dip but they (the investigators) would not see me from where they were standing."
Earlier in the trial, Mr Richardson had told the court that Mr Henderson had shot and wounded the fox.
Mr Richardson and Mr Riley, of Bonchester Bridge, deny breaching the Protection of Wild Mammals (Scotland) Act 2002.
The trial will continue later this month.

Moises Henriques hit 18 runs as the Sixers scored 22 in their extra over, while the Heat made 15 in reply.
Brendon McCullum had earlier scored 46 as the Heat compiled 167-9.
The Sixers looked well set after Henriques' 64, but Ben Dwarshuis had to score two runs off the final ball to tie the game at the Gabba.
Henriques then hit two sixes and a four in the super over.
The Sixers will play the Scorchers, who are two-time champions, in the final at the Waca in Perth.
Britain's economy faces a "prolonged period" of weaker growth as consumer spending slows and business curbs investment, according to a report.
[NEXT_CONCEPT]
A retired police wildlife crime officer has told the trial of two men accused of breaking Scots fox-hunting laws he was waiting in a gulley with a shotgun.
[NEXT_CONCEPT]
Sydney Sixers beat Brisbane Heat in a super over to reach Saturday's Big Bash League final, where they will play Perth Scorchers.