Nutrition the science of food and how the body uses it in health and diease. Essential nutrients substances the body must get from foods b/c it cannot manufacture them all or fast enough to meet its needs. Macronutrient an essential nutrient required by the body in relatively large amounts. Digestion process of breaking down foods in the gi tract into compounds the body can absorb. Kilocalorie measure of energy content in food; one kilocalorie represents the amount of heat needed to raise the temperature of one liter of water by ine degree celsius. Protein essential nutrient, made of amino acids that contains carbon, hydrogen, oxygen and nitrogen. Legumes vegetables, such as peas, beans, that are high in fibre and protein. Hydrogenation process by which hydrogen is added to unsaturated fats, increasing the degree to saturation and turning liquid oil into solid. Trans fatty acids type of unsaturated fatty acids produced during the process of hydrogenation.