BODY-MASS INDEX AND ECONOMIC PRODUCTIVITY

The paper reviews the evidence to date on the nutritional links with productivity and then goes on to provide results from a multi-country study on the effects of increasing body mass index (BMI) on productivity. The research relating nutritional status to work capacity is more consistent than the research linking nutritional status to productivity. None of the studies to date elucidate the pathways through which improved nutrition improves economic productivity. In addition, many of the studies that have been conducted on the nutrition/wage links have been based on samples that contained a disproportionate number of male subjects. The few studies that have disaggregated data by gender report different results for men and women. Research conducted at IFPRI is presented to examine the trends in BMI for men and women across countries and for Kenya to examine the relationships between various measures of nutritional status - BMI and height - and energy expenditures in women. BMIs of men show a more consistent relationship with increasing household income than do the BMIs of women. In the case of the Gambia and Kenya, the mean BMI of women decreases with increasing household income. One reason for the apparently low response of BMI to increasing household income in Kenya is the time allocation patterns of women. Women in the Kenya sample spend the largest proportion of their day in home production activities which are energy intensive. In examining the relationship between nutritional indicators and the time devoted to work, the results suggest a significant, positive association between both BMI and height and the amount of time devoted to work. In the models presented, both BMI and height appear to increase the capacity to carry out work. It is difficult to value much of this work time since a disproportionate share is devoted to home production activities. Some of the more classic methods of measuring economic productivity, such as measuring wage rates, are not relevant for women in this setting. The data from Kenya suggest that more appropriate measures for specifying the value of women's work need to be developed in order to capture some of the nutrition/productivity links which may exist.