We examine the associations between nutrition and mortality at the national level. Altogether four aspects of this association are explored: (1) total calories with expectation of life, (2) dietary composition with expectation of life, (3) total calories with the age patterns of mortality, and (4) dietary composition with the age patterns of mortality. The data consist of life tables and national food balance sheets for 341 populations from 96 countries. A preliminary principal components analysis conducted on the dietary composition data yields three dietary components: (1) the overall quality and quantity of the diet, (2) the relative contribution of carbohydrates versus fats, and (3) the relative contribution of fats versus proteins. The results indicate that expectation of life at birth increases with total calories, with overall quality and quantity of the diet, and with the ratio of fats to proteins. The ratio of carbohydrates to fats is negatively associated with level of mortality. However, evidence indicates that the main effect of the ratio of fats to proteins is reversed when diets are high in quality and that all the effects tend to saturate at high nutrient availability. Variation in nutrition is also strongly associated with the international variation in age patterns of mortality. For example, when expectation of life is held constant, populations with higher quality diets tend to have lower childhood mortality and higher adult mortality. The results indicate that nutritional patterns are highly correlated with much of the worldwide variation in mortality and may be a useful criterion for selecting or predicting the best suited model life table for use on a particular population.