Replacing forage with a mixture of byproducts or replacing corn grain with saturated free fatty acids resulted in an increase in NEL intake. The forage effect was caused by increased DMI and the fat effect was caused by increased energy density. When high-forage diets were supplemented with fat, the increased NEL intake was directed mostly to body reserves but when fat was added to the low-forage diets, the energy was directed mostly to milk production. In early lactation, the lower DMI by cows fed the high-forage diet may have caused nutrients other than energy to be limiting for milk production.