The Mediterranean diet may be healthier than the typical Western diet, but it's more expensive, too, a Spanish study found.
Spaniards who ate greater proportions of olive oil, fish, and vegetables spent nearly a dollar more per 1,000 kilocalorie of energy than those who consumed more red meat, processed meat, and dairy foods, according to Maira Bes-Rastrollo, of the University of Navrra.
"Our results are consistent with previous studies that have shown low-energy-density diets, specifically of the Mediterranean dietary pattern, are associated with higher costs of daily food consumption," the researchers wrote online in the Journal of Epidemiology and Community Health.
They noted that the cost of food influences diet, which may be a challenge to promoting the benefits of a Mediterranean diet and enacting policies that encourage it.
Also, they noted, the growth of the fast-food industry in Spain and in Europe in general has made it more affordable, convenient, and popular to consume a Western diet.
For their study, the researchers surveyed 17,197 university graduates and followed a total of 11,195 from December 1999 to February 2008.
They answered a 136-item food questionnaire to determine whether their diets were more Western or more Mediterranean. Average food costs were calculated from Spanish government data.
The mean age of study participants was 38.6 years, and 60 percent were women.
The researchers found that patients who had the highest scores on the Western diet scale spent less money on food every day -- about $0.80 less per 1,000 kilocalorie.
Those on the Mediterranean diet spent about $0.90 more per 1,000 kilocalorie.
However, the researchers found a significant association between having higher odds of weight gain and those who had the highest daily food consumption costs.
"Unexpectedly, higher daily food costs were associated with the risk of gaining at least 0.6 kilograms per year during follow-up," they said.
The researchers guessed behavior beyond diet may be responsible for the unexpected finding, including individual differences in metabolism and the ability to maintain or lose weight.
Those with the highest daily food costs also had significantly higher baseline body mass index (BMI), which suggests that heavier participants were more prone to weight gain because of other lifestyle, metabolic, or genetic factors.
This group also had a higher consumption of processed meats, precooked foods, soft drinks, and fruit juices.
"Nonetheless, this finding deserves further investigation to prove its consistency in other populations," the researchers said.
They said the study was also limited in that it may not generalize outside the Spanish population. They noted that there will always be a variation in the cost of food between regions of the country, seasons, and types of establishments from which the food is purchased.
"The Mediterranean dietary pattern may become more appealing than the Western dietary pattern if it were made more affordable," they said, adding that taxes on unhealthy foods or subsidies for healthy foods are policy options.