This seems more the opposite. It says,

For example, we observed a missense mutation in the CR1 gene, the derived state of which has a frequency of 85% in Africans, but which is absent elsewhere. As this gene modulates the severity of malarial attacks in Papua New Guineans,our analysis strongly suggests that this particular CR1 mutation has been positively selected for in Africans because it modifies host susceptibility to malaria. Another important selective pressure that has confronted modern humans is adaptation to variable nutritional resources. ... ENPP1 harbors a mutation with a derived state known to protect against obesity and type II diabetes that is present in B90% of non-Africans but virtually absent in Africans.