Midterm 2 Review

Chapters 5-8

Midterm #2

• Chapters 5-8• Multiple Choice and True/False (50)• Multi-part Short Answers (4)• Bring: Scantron, Non-graphing calculator,

pencil, eraser

Chapter 5: Carbohydrates

• Carbohydrates include sugars, starches, and fibers

• Major food sources: plants• Two main carbohydrate types:– Simple (sugars): mono + disaccharides– Complex (starches and fiber)

• Bond: alpha or beta glycosidic bonds

Carbohydrates

• High Fructose Corn Syrup• Complex Carbohydrates– Starch vs. Glycogen– Amylose (straight) vs. Amylopectin (branched)– Fiber: non-digestible before entering large intestine

• Soluble: dissolves in water gel-like slows digestion – Fermentable

• Insoluble: does not dissolve in water creates a bulk larger, softer stool– Fermentable (Resistant Starch) vs. Non-Fermentable

Fiber Diagram

Carbohydrates Digestion & Absorption

• Mouth: Salivary amylase• Small intestine:– Enzymes: pancreatic amylase, brush border enzymes– End product: Glucose– Liver stores and releases glucose to maintain blood

glucose• Large intestine:– Bacteria in colon digests rest of carbohydrates,

soluble fiber, and resistant starch (a type of insoluble fiber) to gas + short chain fatty acids energy supply for colon cells

Regulating Blood Glucose Levels

Carbohydrates and Health

• Glycemic Index• Hyperglycemia vs. Hypoglycemia– Hyperglycemia consequences: sweet urine,

ketosis/acidosis (if you are also diabetic)– Hypoglycemia: • Reactive Hypoglycemia• Fasting Hypoglycemia• Consequences: ketosis/acidosis, coma death

– Diabetes I, II, Gestational Diabetes

Carbohydrates in your diet

• Nutritive vs. Non-nutritive sweeteners– Nutritive:• Natural, Refined, Sugar Alcohol• Can be “sugar free,” but not always calorie free

– Non-Nutritive: “Artificial sugar”• Saccharin (bladder cancer), Aspartame (PKU),

Acesulfame K (Stable under heat), Sucralose

Chapter 6: Lipids

• Types: Triglycerides, Phospholipids, Sterols• Made of: Glycerol + Fatty Acids• Bonds and Saturation:– Saturated fatty acids vs. Unsaturated fatty acids

(MUFA, PUFA)• Saturated fatty acids: all single bonds• Unsaturated fatty acids: Cis (natural) vs. Trans fatty

acids (partial hydrogenation)

• Essential vs. Non-essential fatty acids

Lipids• Triglycerides– Functions: energy storage, insulation/protection, etc.– Visceral vs. Subcutaneous fat– Food sources by most prevalent type: Saturated

(animal) vs. Polyunsaturated (plants)• Phospholipids: – Functions: Emulsifier (bile, lingual lipase), Structural

element for cell membrane (lipoprotein carrier)• Sterols– Functions: structural component, precursors to other

substances

Lipid Absorption

Lipoprotein Pathway Summary

Lipid Digestion

• Fat hydrogenation Pros/Cons• Lipids and Health• AHA diet and lifestyle recommendations• Metabolic Syndrome• Cancer

Proteins

• Made up of: Amino acids– Essential, Non-Essential, Conditionally essential

• Bond: Peptide bond• Denaturalization of Protein (factors and

consequence)• Functions of Body Proteins

Summary of Protein Digestion and Absorption

Function of Blood Amino Acid Pool

Protein in the Diet

• Nitrogen balance• Recommended protein intake– Adult RDA = 0.8g/kg of body weight– Infants have highest needs relative to body weight

• Physical stress increase your body’s needs for proteins

• Protein Quality: Complete vs. Incomplete• Vegan vs. Vegetarian, Pros/Cons

Health Effects of Protein

Too Little Protein• Protein-energy malnutrition

(PEM)– Kwashiorkor: severe protein

deficiency– Marasmus: severe calorie

deficiency

Too Much Protein• Heart Disease• Obesity• Osteoporosis• Cancer

Energy Balance and Weight Management

• Energy input vs. output• Food intake is regulated by sensations of

hunger, satiation, satiety, appetite– Physiological vs. psychological

• Internal (physiological response) vs. External cues (environment)– Internal: sense of fullness, NPY, Ghrelin, Leptin– External: diet composition, sensory properties,

portion size, environment/social, emotion

How does our bodies use energy?1. Resting energy expenditure or

(REE)2. Thermic effect of food (TEF)3. Physical activity (PA)

• REE + TEF + PA = Total Energy Expenditure

Measuring Body Weight and Fat

• Body composition– Is the relative amount of fat and lean muscle mass

• Assess body weight via BMI• Assess body fat via DEXA/DXA, Underwater

weighing, BodPod, Skinfold measurements, Bioelectrical impedance

Overweight and Obesity

• US: 2/3 or 66% of American adults are overweight/obese

• Factors in development of obesity– Biology: genetics, race, fat cell development,

sex/age– Social environmental factors: socioeconomic

status, built environment, social factors– Lifestyle and behavior: psychological, physical

activity

• Weight cycling or “yo-yo dieting”

Diet and Eating Habits

• Adopting a healthy behaviors• Crash diets don’t work• Balancing energy sources: Carbs (45-65%),

Fats (20-25%), Proteins (10-35% of total calories)

• Weight management approaches• Underweight

Resources

• Your required textbook• Lecture Notes• Practice Quiz (online)• Classmates• Professor