Based on Christine's commentary so far, I want to emphasize something I touched on in my contribution earlier in the debate.
There are existing data linkng lack of dietary diversity (over-consumption of starches and sugars) to low incomes in Southern Africa. See the work of AFSUN (African Food Security Urban Network) and the article I co-auhtored in the attached issue of Right to Food and Nutrition Watch Magazine last year (attached). I think it is also establlshed through other evidence that lack of dietary diversity is linked to life-style diseases and to obesity. From this we can conclude that there is already some evidence that, in the urban transition, the malnutrition associated with obesity and life-style diseases is not associated with income increase and over-eating as is often asserted. Rather, it seems to be associated with urban poverty. The lack of afforbale food for the urban poor is a major issue.
One of the ways this is being tackled in Africa is through encouraging urban agriculture. This enables poor urban residents to produce micro-nutrients for themsleves, in the form of animal source foods such as milk and eggs as well as fresh fruit and vegetables. These may also increase available supplies in urban areas and help increase employment and incomes. I also attach the book Healthy City Harvests, published in 2008 which contains extensive research on urban agriculture, including establishing the link between urban agriculture and improved food and nutirtion security.