OBJECTIVE:To analyze the evolution of relative prices of food groups and its infl uence on public healthy eating policies.
METHODS:Data from the municipality of São 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 defl ated 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 modifi ed 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, fl our 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. Trends in the evolution of Brazilian eating patterns show a signifi cant increase in the consumption of processed foods with high levels of simple sugars, sodium and lipids (foods which characterize an unhealthy diet). Associated with reduced consumption of fresh foods (standard markers of healthy eating). 10 The nutritional profi le of Brazilian adults has changed signifi cantly since the 1970s. This transition process is characterized by the gradual decrease in the proportion of malnourished individuals and the continued increase in prevalence of obesity. 12 The change in Brazilian eating patterns is allied to life style changes due to urbanization and technological advances, such as the progressive reduction in energy expenditure at work and on household tasks. This results in an increase in the prevalence of overweight and obesity. 18,19 The result of the changing nutritional panorama in the country includes increased prevalence of overweight and obesity in the population and changes in the national morbidity profi le, burdening the health care system. 3,15,17 Food consumption is infl uenced by a wide variety of factors, especially economic determinants, such as relative prices and income. 4,11,17,a Since the end of the 1930s, factors linked to supply, such as improved technology and increased scales of production, accompanied by increased demand, have enabled the price per calorie of processed food to be reduced. 8,b Studies show that the price per calorie of fresh food, more subject to weather conditions and pests ...