Nutrition in pregnancy has been recognized for millennia as being important, but the current nutritional practices of pregnant women often do not conform to what we already know to be optimum. Pregnant women are increasingly entering pregnancy overweight as the dietary habits of young women deteriorate in many societies. This increase in overweight was accompanied by a 5-fold increase in gestational diabetes within 15 years in Norway, together with an unprecedented increase in the prevalence of large babies. This is accompanied by increasing risks of fetal malformations, damage to mother and child during parturition, and an increased risk of both obesity and type 2 diabetes in mother and the adolescent child. The prevalence of overweight girls is therefore a public health challenge with intergenerational implications.