Macronutrients – Quick Review Notes

Learning Targets

  • Identify functions & classifications of carbohydrates, fats & proteins
  • Plan balanced meals that meet macronutrient needs

Physical Activity & Food-Guide Basics

  • Adults: ≥30 min moderate activity most days; children: 60 min
  • Food-guide (≈2000 kcal):
    • Grains 6 oz (≥½ whole)
    • Veg 2.5 c
    • Fruits 2 c (limit juice)
    • Dairy 3 c low-/non-fat
    • Meat/Beans 5.5 oz lean, seafood, legumes
    • Oils 6 tsp (favor plant/fish); limit solid fats & added sugars
    • Water ≥8 glasses/day

Macronutrients – Overview

  • Needed in largest amounts: carbohydrates, fats (lipids), proteins

Carbohydrates (CHO)

  • Formula Cm(H2O)_n – primary energy source

Classification

  1. Monosaccharides (absorb directly)
    • Glucose (blood sugar; via gluconeogenesis from protein)
    • Fructose (sweetest; fruit, honey → glucose)
    • Galactose (from lactose; infant brain dev)
  2. Disaccharides (hydrolyzed before absorption)
    • Sucrose = glucose + fructose
    • Lactose = glucose + galactose
  3. Polysaccharides (complex)
    • Starch → sustained energy
    • Dextrins (starch breakdown; thickeners)
    • Cellulose (dietary fiber)
    – Soluble: fruits, legumes, oats (↓glucose spike)
    – Insoluble: wheat bran, whole grains (GI motility)
    • Pectin (jellies; ↓cholesterol, toxins)
    • Glycogen (stored glucose)

Key Health Effects

  • Weight control, ↓CVD, ↓cancer risk, diabetes management, healthy GI

Lipids (Fats)

  • Insoluble in water; body energy reserve (~34\% kcal)

Classification

  1. Simple – Triglycerides (glycerol + 3 FA)
  2. Compound – plus other groups
    • Phospholipids (lecithin, cephalins, sphingomyelins)
    • Glycolipids (cerebrosides, gangliosides)
    • Lipoproteins: HDL "good", LDL "bad"
  3. Derived
    • Fatty acids: saturated (animal), monounsaturated (olive/peanut), polyunsaturated (vegetable oils)
    • Glycerol (osmotic effect)
    • Steroids (cholesterol)
  • Trans-fat (partially-hydrogenated oils) banned; raises CVD risk

Health Effects

  • Saturated/ trans fats ↑ heart disease, cancer, obesity
  • Mono & polyunsaturated fats ↓ LDL, ↓ CVD risk

Protein (CHON)

  • 20 amino acids – growth, repair, enzymes

Classification

  1. Simple (yield only AA)
    • Albumin, globulin, glutelin, prolamin, albuminoid, histone/protamine
  2. Compound (protein + non-protein group)
    • Nucleo-, muco-, lipo-, phospho-, chromo-, metallo-proteins
  3. Derived (partial hydrolysis products)

Amino Acids

  • Essential (cannot synthesize): histidine, valine, tryptophan, threonine, phenylalanine, methionine, lysine, isoleucine, leucine ➜ obtain from varied plant/animal foods
  • Non-essential: body can make
  • Complete proteins: animal sources
  • Incomplete: plant sources (combine for completeness)

Protein-Energy Malnutrition

  • Marasmus (chronic total deprivation)
  • Kwashiorkor (acute protein lack)

Key Nutrition Calculations

  1. Desirable Body Weight (DBW)
    • Men: 50 + 0.91\,(height{cm} - 152.4) • Women: 45.5 + 0.91\,(height{cm} - 152.4)
    • Alternative: IBW = 22\times(heightm)^2 (men) IBW = 22\times(heightm - 0.10)^2 (women)
  2. Basal Energy Needs
    • Men: 1\,kcal\cdot kg^{-1}\cdot hr^{-1} \times DBW \times 24
    • Women: 0.9\,kcal\cdot kg^{-1}\cdot hr^{-1} \times DBW \times 24

Diet & Meal Planning Tips

  • Variety ensures nutrient balance
  • Use iodized salt & fortified foods for micronutrients
  • Emphasize whole grains, fruits, veg, lean proteins, healthy oils
  • Limit saturated, trans fats, added sugars, sodium
  • Pair plant proteins to supply all essential AAs
  • Regular exercise & good hygiene complement dietary measures