Cut fruit and vegetable prices in half and people will load up on them, according to a new study that suggests price regulation may play an important role in future public policy.
"Many people argue that we should educate the population better about healthy eating - however our results clearly show that that is not the direction to go," lead author Wilma Waterlander told Reuters Health by email.
"Price changes are really needed," said Waterlander, a research fellow at the School of Population Health at the University of Auckland in New Zealand.
In past surveys, people indicated they would buy more fruit if prices were lower, but there hadn't been rigorous supermarket tests to confirm the idea.
For the new test, Waterlander and her colleagues randomly divided 151 Dutch supermarket shoppers into four groups and gave each group half-off coupons (good for six months) for fresh, canned and frozen produce; healthy cookbooks and phone consultations with a dietitian; both coupons and nutrition advice or neither.
The researchers collected supermarket receipts before the programme began, one month into the discount period, three months in, at six months (as the discounts expired) and three months after the programme ended.
At the six-month point, households with coupons and cookbooks bought about 12 pounds more produce for a two-week period than they had before the study. People given only coupons bought almost nine pounds more. The phone conversations and cookbooks, with "easy, tasty and cheap" recipes using lots of fruits and vegetables, did not affect food purchases on their own.
"I think it tells us that we know we need to do more than just educate people," Glorian Sorensen, who studies the health impacts of community interventions at the Dana-Farber Cancer Institute in Boston, Massachusetts, told Reuters Health.
With coupons, participants not only bought more fruit and vegetables, but also ate more of them, based on responses to a questionnaire. Sixty per cent of participants ate the recommended daily amount of fruits and vegetables at the end of the study, compared to 42 per cent at the beginning, according to findings published in the American Journal of Clinical Nutrition.
The researchers were pleased to see that people didn't use the money they saved to buy more food in other areas of the store.
"This is crucial, especially in the light of obesity prevention," Waterlander said.
Varying effects by country
Price cuts would likely be most effective in countries where produce is most expensive, like the Netherlands, Waterlander said. In that country, an ongoing "supermarket war" has major chains competing for customers by pricing popular items like beer at a loss, while keeping the prices of fruits and vegetables high to compensate, she explained.
Produce prices are similarly high in much of Europe, Waterlander added, whereas in the US, US$20 billion (S$25 billion) in farm subsidies annually keep produce prices relatively low.
Only 14 per cent of Americans get the recommended two fruits and three vegetables per day, which provide essential vitamins, minerals and fiber and may reduce the risk of cancer and chronic diseases, according to 2010 data from the US Centers for Disease Control and Prevention.
"For people who are affluent, changing the price is probably not going to make a big difference," Karen Glanz, who studies community health and behaviour at the University of Pennsylvania in Philadelphia, told Reuters Health.
For people who are poorer and most affected by obesity and diabetes, price is a big factor, said Glanz, who was not involved in the study.
Only about half of the farmers markets in the US accept food stamps, but that number has been increasing lately, which could help make fresh produce more available to low income families, Glanz notes.
But it will be a while before major changes happen in supermarkets, which are still where Americans get most of their food, she said. "It's profitable for the bottom lines to promote the unhealthy options."
More studies need to look at long term effects on diet and determine how deep the discount needs to be before it's implemented in policy, Sorensen said.
"It might seem obvious - make it cheaper and people buy more - but it is not that simple," Waterlander said.