Don't know of studies that have specifically targeted Black women, because the primary issue is inner.city poverty. Food choices and outcomes such as obesity, poor health etc seem to follow as a result. The journal Health Education and Behavior has published some results of smaller studies, and some cities such as Chicago and Seattle have written reports on inner-city poverty and food choice. For larger studies your best bet will probably be the USDept. of Health Education and Welfare and /or the USDept of Agriculture.