Inorganic anions nitrate and nitrite influence metabolic rate and glucose homeostasis. Infusion of nitrite iv caused an acute drop in resting energy expenditure (oxygen consumption) and nitrate, when given perorally, caused a reduction in oxygen consumption during exercise and a depression of the increase in blood glucose observed after an oral glucose tolerance test. The doses of nitrate and nitrite did not cause any detectable change in methemoglobin levels of blood. Also, nitrate and nitrite did not alter lactate levels in blood. This discovery provides useful treatments to regulate the energy expenditure and glucose homeostasis of a mammal by administration of inorganic nitrite and/or nitrate.