Science of Nutrition and Tools of a Healthy Diet

Nutrition

The science of food, nutrients, and the body's process of metabolizing them.

Nutrients

Substances essential for health that the body cannot make or makes in insufficient amounts.

Macronutrients

Nutrients needed in large quantities: carbohydrates, proteins, lipids, and water.

Micronutrients

Nutrients needed in small amounts: vitamins and minerals.

Carbohydrates

Composed of carbon, hydrogen, and oxygen; provide 4 kcal/g of energy.

Proteins

Composed of C, O, H, and nitrogen; provide 4 kcal/g; main structural body components.

Lipids

Insoluble in water, composed of C, O, and H; provide 9 kcal/g of energy.

Triglycerides

Major form of fat in foods and body; 3 fatty acids attached to a glycerol backbone.

Saturated Fats

Mostly solid at room temperature, mainly from animal sources; raise blood cholesterol.

Unsaturated Fats

Mainly liquid at room temperature and plant-based; generally healthier than saturated fats.

Essential Fatty Acids

Linoleic acid (Omega-6) and Alpha-linolenic acid (Omega-3) supplied by diet.

Trans Fatty Acids

Partially hydrogenated oils banned in the U.S. due to health risks.

Vitamins

Organic compounds that enable chemical reactions; water-soluble and fat-soluble.

Minerals

Inorganic substances not destroyed by cooking; do not yield energy.

Water

Nutrient needed in largest quantity; acts as a solvent, lubricant, and transport medium.

Functional Foods

Provide health benefits beyond traditional nutrients due to phytochemicals.

Calorie

Amount of heat energy needed to raise 1 gram of water 1 degree Celsius.

Kilocalorie

Amount of heat energy needed to raise 1000 grams of water 1 degree Celsius.

Hunger

The physical need for food, such as stomach rumbling or low blood sugar.

Appetite

The psychological desire to eat, driven by cravings.

ABCDEs of Nutritional Assessment

Anthropometric, Biochemical, Clinical, Dietary, and Environmental assessments.

Registered Dietitian (RD/RDN)

Qualified professional with an approved degree, 1000 hours practice, and national exam.

Dietary Reference Intakes (DRIs)

Official dietary standards for the U.S. and Canada evaluating nutrient intakes.

Estimated Average Requirements (EARs)

Daily nutrient amounts estimated to meet the needs of half the people in a life stage.

Recommended Dietary Allowances (RDAs)

Daily nutrient amounts sufficient to meet the needs of nearly all (97-98%) individuals.

Adequate Intakes (AIs)

Daily intake amounts set when insufficient research exists to establish an EAR.

Tolerable Upper Intake Levels (ULs)

Maximum daily intake amounts unlikely to cause adverse health effects.

Estimated Energy Requirements (EERs)

Average daily energy need for each life-stage group to promote healthy weight.

Acceptable Macronutrient Distribution Ranges (AMDRs)

Intake ranges for carbs, proteins, and fats associated with reduced chronic disease risk.

Nutrient Density

Amount of essential nutrients a food provides relative to its calorie content.

Daily Values (DVs)

Generic FDA standards on Nutrition Facts panels based on RDIs and DRVs.

Nutrient Content Claims

Closely regulated FDA claims describing nutrients in a food, such as low fat.

Health Claims

Describe a relationship between a disease and a nutrient, food, or food constituent.

Structure/Function Claims

Describe how a nutrient affects body structure or function; not FDA-approved.

Energy-Dense Foods

High in calories but weigh very little, such as nuts and fried foods.

Low-Energy-Dense Foods

Contain large amounts of water and few calories, such as fruits and vegetables.

Dietary Guidelines for Americans

U.S. government foundation for nutrition policy, published every 5 years by USDA and DHHS.

MyPlate

USDA food guide introduced in 2011 depicting key elements of a healthy diet on a plate.