In contrast, protein deficient diets have been implicated as important regulators of metabolic programming and later health outcomes in mice and men [43, 44, 45, 46] . Gestational protein deficiency in the mother leads to intra-uterine growth delay in the offspring. However, when such offspring is then cross-fostered onto dams on a control diet, they show a phase of rapid catch up growth during lactation [47] . The combination of poor foetal and rapid post-natal growth leads to increased susceptibility for metabolic disease and reduces life-span [48, 49] . In contrast, nutritional restriction during lactation leads to a growth delay in rodent pups which is maintained throughout life [48] .