Way too late, but...
I facilitated a one and a half day session on household food security and nutrition during a summer school on sustainable mountain development at the end of June. Part of this was group work and one of the groups decided to work on a valley in the Peruvian Andes. Their diagnosis (which caught me by surprise) was that the local economy was undermined by the Conditional Cash Transfer programme: people would stop buying locally and spent their cash in the local supermarket (which was doing great :-)). So no good for local farmers (who may have to apply sooner or later to the programme) and no good for consumers (not sure shifting from local foods to supermarket food is necessarily the healthy choice).
This was clearly anecdotal. Has any research been carried out to look at the impact of social protection programmes on food practices and diets?