Chapter
1
Nutrients and Nourishment
Why Do We Eat the Way We Do? • Personal Preferences • Sensory Influences: Taste, Texture, and Smell • Habits • Comfort/Discomfort Foods • Advertising and Promotion • Food and Diet Trends • Social Factors • Nutrition and Health Beliefs
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Why Do We Eat the Way We Do? • Environmental • • • • • •
Economics Lifestyle Availability Cultural influence Religion Social-Ecological Model
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The American Diet • Americans know about healthful food choices. • Eating habits do not always reflect this knowledge.
Introducing the Nutrients • Definition of nutrients • Food = mixture of chemicals • Nutrients = essential chemicals • Six classes of nutrients
Introducing the Nutrients • Carbohydrates • Sugars and starches • Functions • Energy source
• Food sources • • • •
Grains Vegetables Fruits Dairy products
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Introducing the Nutrients • Lipids • Triglycerides (fats and oils), cholesterol, and phospholipids • Functions • Energy source, structure, regulation
• Food sources • Fats and oils • Meats • Dairy products
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Introducing the Nutrients • Proteins • Made of amino acids • Functions • Energy source, structure, regulation
• Food sources • Meats • Dairy products • Legumes, vegetables, grains
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Introducing the Nutrients • Vitamins • Fat-soluble: A, D, E, K • Water-soluble: B vitamins, vitamin C • Functions • Regulation
• Food sources • All food groups
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Introducing the Nutrients • Minerals • Macrominerals and trace minerals • Functions • Structure, regulation
• Food sources • All food groups
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Introducing the Nutrients • Water • Most important nutrient • Functions • Structure, regulation
• Food sources • Beverages • Foods © Photodisc
Introducing the Nutrients • Energy in foods • Measured in kilocalories (kcal)
Introducing the Nutrients • Energy in Foods • When is a Kilocalorie a Calorie? • How can we calculate the energy available from foods? • Be food smart: Calculate the percentages of calories in food
Calculating Energy in Foods • One bagel plus 1.5 ounces of cream cheese contains 39 grams of carbohydrate, 10 grams of protein, and 16 grams of fat • • • •
39 g carbohydrate x 4 kcal/g = 156 kcal 10 g protein x 4 kcal/g = 40 kcal 16 g fat x 9 kcal/g = 144 kcal Total = 340 kcal
Diet and Health • Obesity • Behavior • Environment • Genetics
• Physical Activity
Applying the Scientific Process to Nutrition • Common study designs used in nutrition research • • • •
Epidemiological Animal Cell culture Human: case control and clinical trial
• Publishing experimental results
Headlines Can Be Confusing • Sorting Facts and Fallacies in the Media
Finding Scientific Information Versus Misinformation • As scientific information is made accessible to more and more people, less detail is provided and more opinion and sensationalism are introduced. • Sources include professional journals, scientific magazines, generalist magazines and newspapers, nightly news bites, and unattributed Internet sites.
Evaluating Information on the Internet: Red Flags of Junk Science • Recommendations that offer a quick fix • Dire warnings of danger from a single product or regimen • Claims that sound too good to be true • Simplistic conclusions drawn from a single study • Dramatic statements that are refuted by reputable scientific organizations
“American Diet” • American cuisine is truly a melting pot of cultural contributions to foods and tastes. Although Americans receive and believe many messages about the role of diet in good health, these beliefs do not always translate into better food choices.