Although there is evidence that social cash benefits help shifting the food intake towards better (higher quality) foods among the poor, much of that impact could either come too late for better anthropometric results (due for example to means tested targeting practices penalizing children early in their lives) or get wasted by poor access to and/or lack of uptake of parallel, nutrition sensitive interventions (good sanitation, hygiene, care practices etc). See more on related links here http://www.unicef.org/esaro/5483_social_protection.html and here http://www.thelancet.com/series/maternal-and-child-nutrition
Reform efforts require, therefore, careful context specific analysis and inputs from economists as well as nutritionist, anthropologists, sociologists and development practitioners. This may help decision makers avoiding the political, economic and population burden of half-baked ad-hoc solutions and endorsing integrated, multi-dimensional response strategies with positive individual and social returns along several dimensions of human development.
Gaspar Fajth, UNICEF