Datamonitor quizzed more than 1,000 people in the UK as part of an international survey, in the run-up to Fairtrade Fortnight, which begins today (28 February).
While Fairtrade products are becoming increasingly popular, according to the published research, consumers are wary of increased price.
Datamonitor predicts that by 2014, Fairtrade food spend will almost double to £525m, while sales of Fairtrade alcoholic drinks will more than double to £57m, and sales of Fairtrade non-alcoholic beverages will increase by around 50% to £728m.
Only 14% of people regularly buy Fairtrade products, with a further 47% buying them "occasionally". Those who do buy the products say it is an important factor when shopping.
Mike Hughes, analyst at Datamonitor, said: "UK consumers are buying into the ethical marketing message of Fairtrade products, as well as the additional authenticity and provenance cues brought about by learning more about origins and production.
"However, while the market will continue to grow, consumers show a reluctance to pay more for products given an ethical positioning, unless there is also some immediate enjoyment-led feature to be had.
"This means that in order to target a wider consumer base, more emphasis has to be placed on elements such as great taste and freshness of products. The key challenge for manufacturers is that any wider marketing does not subtract from the ethical message around tackling global poverty, that the certification passionately focuses on."
Sainsbury's claims to be the world's largest seller of Fairtrade products. I has led the trend by converting all its bananas to Fairtrade in 2007, following this with sugar, tea and coffee products.
Liz Jarman, head of Fairtrade at Sainsbury's said: "We are absolutely focused on providing Fairtrade to our customers for free. So, where Fairtrade is the only own-brand option in our stores, as is the case with bananas, we make sure that our prices remain on a par with those of our non-Fairtrade competitors. This encourages customers to continue to shop with us and to continue to buy Fairtrade."
Sainsbury's is also introducing the first commercially produced coffee from the Democratic Republic of Congo for more than 40 years, as war has stripped the country of working markets.
The supermarket will donate 30p from each pack to Comic Relief. A second coffee, Red Nose Day coffee, is sourced from Malawi.
Andrew Mitchell, the secretary of state for international development, said: "Trade drives growth, which in turn creates jobs and wealth in communities. Through trade we can help people to pull themselves out of poverty.
"Ensuring farmers and other producers get a fair price for their produce and effort is central to this. Trade will soon become a central theme across our aid programme, particularly in Africa, helping developing countries, including those emerging from conflict, tackle the obstacles that prevent them from making the most of trading opportunities."
Sainsbury's has been pushing steadily into sustainability, launching green energy centres in 500 stores this year, and focusing on sustainably sourced fish.
Other supermarkets are keen to show off their green credentials. Waitrose started selling Fairtrade condoms last week, and produced an ad to show off its sustainbly caught cod.
The Co-operative also wants to increase the proportion of Fairtrade products it sells, and aims to have 90% of products sourced from developing nations Fairtrade by 2013.