Chapter 6: Forming a Plan for Good Nutrition ØNutrition is the study of nutrients and the way the body processes them ØThe Recommended Dietary Allowances (RDAs) were established to prevent acute deficiency diseases ØThey are being revised to prevent or delay the onset of chronic diseases, today’s primary nutrition-related problem

Essential Nutrients ØThe essential nutrients are carbohydrates, fat, protein, vitamins, minerals, and water ØEssential nutrients must be supplied by the diet ØThe energy nutrients are carbohydrates, fat, and protein because they supply the body with calories ØA calorie is a measure of food energy

Calories (1) ØA gram of carbohydrate or protein provides 4 calories of energy ØA gram of fat provides 9 calories ØA gram of alcohol provides 7 calories, but is not an essential nutrient

Calories (2) ØAt least 55% of the diet should be in the form of carbohydrates; a minimum of 45% of these should be complex carbohydrates ØNo more than 30% of calories should come from fat ØApproximately 15% should come from protein

Carbohydrates ØCarbohydrates are sugars and starches from plants ØMonosaccharides are simple carbohydrates, or sugars ØPolysaccharides are complex carbohydrates, or starches ØStarches help the body maintain normal blood-sugar levels

Protein (1) ØProteins are composed of amino acids and contain nitrogen ØOf the 20 amino acids, nine are essential (must be supplied by the diet) ØComplete proteins contain all essential amino acids; high-quality proteins contain the amino acids in the proportions needed by the body (usually found in meat and dairy foods)

Protein (2) ØIncomplete proteins do not contain amino acids in proportions needed (plant foods) ØLegumes, such as soy, are complete proteins ØMost people require 0.36 grams per pound of body weight of protein daily ØExcess protein is stored as fat; high protein intake strains the kidneys and causes the body to excrete calcium

Fat (1) ØFats (lipids) are composed of chains of carbon atoms with hydrogen atoms attached ØSaturated fats carry all the hydrogen atoms they can ØMonounsaturated fats have room for two hydrogen atoms ØPolyunsaturated fats have room for four or more hydrogen atoms

Fat (2) ØHydrogenated products have hydrogen atoms added into them so they are more resistant to spoilage (and more saturated) ØHydrogenation yields a new type of fat called transfatty acids ØOlestra is a synthetic fat that cannot be digested, so it has no calories

Fat (3) ØCholesterol is found only in animal products ØThe body requires 3 calories to digest 100 calories of dietary fat but 23 to 27 calories to digest 100 calories of carbohydrates ØDietary fat intake should be less than 30% of the total diet and should be low in saturated fat

Vitamins (1) ØVitamins are organic compounds necessary in small amounts for good health; they do not supply energy ØFat-soluble vitamins include A, D, E, and K; excess amounts are stored in the body ØAntioxidant vitamins (C, E, and carotenoids) help neutralize the activity of free radicals ØFree radicals cause cellular damage that contribute to disease

Vitamins (2) ØHealthy adults who eat a variety of foods do not need vitamin supplements ØExceptions for specific supplements might include people who are 65 or older; consume fewer than 1000 calories per day; have a digestive tract disease; smoke; drink alcohol excessively; are pregnant or lactating; are vegetarians

Minerals ØMinerals are inorganic compounds that fulfill a variety of functions in the body ØMacrominerals (major minerals) are required in large amounts—more than 100 mg/day ØMicrominerals (trace minerals) are required in small amounts—less than 100 mg/day ØCalcium is the mineral most commonly deficient, especially in women

Water ØNext to air, water is the substance most necessary for survival ØSixty percent of the body’s weight is water ØRecommended daily fluid intake is 8 to 12 cups—preferably tap water ØIf you are thirsty, your body has already lost too much fluid

Other Nutrients ØPhytochemicals are active compounds that exist naturally in all plant foods ØBotanicals (phytomedicinals), usually called herbs, are considered dietary supplements and are not regulated by the FDA ØSoluble fiber adds bulk to stomach contents ØInsoluble fiber speeds transit time through the large and small intestines

Dietary Guidelines for Americans (1) ØEat a variety of foods (see the Food Guide Pyramid) ØBalance food intake with physical activity; maintain or improve your weight ØChoose a diet with plenty of grain products, vegetables, and fruits

Dietary Guidelines for Americans (2) ØChoose a diet low in fat, saturated fat, and cholesterol ØChoose a diet moderate in sugars ØChoose a diet moderate in salt and sodium ØDrink alcoholic beverages in moderation— one drink per day for women and two drinks per day for men

Other Nutrition Concerns ØPregnancy imposes a greater demand for some nutrients ØCarbohydrates are the main energy source for anaerobic and high-intensity aerobic exercises ØFood labels provide helpful information about nutrients associated with common chronic health problems