This report explores the importance of nutrition for Tanzania. It demonstrates that the prevalence of malnutrition is very high. In fact, Tanzania appears to be affected by a double burden of malnutrition, with a very high incidence of undernourished children, but with a high prevalence of overweight and obese adults as well, particularly in urban areas. The report highlights the high (economic and welfare) costs associated to such high rates of malnutrition by discussing the consequence of malnutrition for infant mortality, education outcomes, the health system and labor productivity. For nutrition to be successfully advanced high level support is needed. Efforts to advance nutrition in Tanzania have made before, with the earliest attempts dating back to the late 1970s. Most have not been very successful. To enhance the likelihood of success this time, commitment from all stakeholders is needed. A social contract that is announced at a public event by a high level policy maker may be one way to commit the actors to change. Such a social contract would have to set clear objectives and a timeline, it would have to define roles and responsibilities of the various stakeholders and provide an accountability framework. The high incidence of malnutrition thus presents an opportunity to enhance school performance, reduce maternal and infant and child mortality and to improve the ability of the labor force to be productive.