[Evolution of the relative prices of food groups between 1939 and 2010 in the city of Sao Paulo, Southeastern Brazil].

OBJECTIVE To analyze the evolution of relative prices of food groups and its influence on public healthy eating policies. METHODS Data from the municipality of Sao Paulo between 1939 and 2010 were analyzed based on calculating index numbers. Data from the Economic Researches Foundation Institute price database and weight structures (1939 to 1988) and from the Brazilian Institute of Geography and Statistics (1989 to 2010) were used to. The price database was organized, its consistency tested and prices were deflated using the consumer price index. Relative prices were calculated and associated to food categories and groups, according to the food pyramid guide adapted for the Brazilian population. The price indices for each group were calculated according to Laspeyres modified formula. The general food price index was compared with the indices for each food group and respective category: fresh food, processed food, beverages, meat, legumes, milk and eggs, cereals and root vegetables and eating out. RESULTS Price indices for fat, oil, spices, sugars and sweets and processed food showed relative price reduction. Fresh food, such as fruit and vegetables, showed an increase in relative prices. Other food groups, such as cereals, flour and pasta, meat, milk and egg, showed a steadier long term trend in relative prices. CONCLUSIONS The evolution of relative prices of food in the city of Sao Paulo demonstrates a negative trend towards healthy eating at household level in the long run.