Changes in the household calorie supply during the 1994 economic crisis in Mexico and its implications on the obesity epidemic.

To characterize the effects of the 1994 economic crisis on calorie sources of Mexican households, five nutrition surveys done every leap year (1992-2000) in national representative samples (> 10,000 households) were analyzed. Each household was visited during 7 days to collect data on foods purchased, exchanged or home-grown and their monetary value. We selected 88 food items to calculate kilocalories/ person/day and cost in pesos/megacalorie (CPMC) for rural-urban strata (localities < 2500, > or = 2500). The food items were classified in 8 groups and the summation of kilocalories and CPMCs of items in each group were our units of analysis. Linear regressions for 1992-2000 were performed, and slopes and intercepts were used to characterize changes. Available calories showed very little change at the height of the economic crisis. Expensive calories (meat in urbans, eggs and milk in rurals, and industrialized meat and soft drinks in both) tended to increase, whereas the most inexpensive staples (cereals, legumes, sugars) decreased their share in both strata. An increase in obesigenic calories was seen, notably in soft drinks, despite a cost increase second only to meat. Main conclusions were: (1) the economic crisis did not affect total calories availability in Mexican households; (2) the 1992-2000 trends in calorie sources were contrary to any crisis effect in rurals and urbans (i.e., expensive foods increased and inexpensive staples decreased); (3) there were sizable rural-urban differences in number, source, and cost of calories; and (4) obesigenic calories increased and soft drinks emerged as a food with its own dynamic.