Macronutrients

Macronutrients

1. Carbohydrate

   • Fuel sources
     • Blood glucose
       • From liver glycogen
       • Increased usage with intensity
     • Muscle glycogen
       • GREATLY increased usage with intensity
   • Rely more on CHO during high-intensity exercise
     • Rate of energy transfer 2x fat/protein
   • Storage
     • 500 g (2000 kcal)
     • Plasma glucose
       • 4 g (16 kcal)
     • Liver glycogen
       • 100 g (400 kcal)
     • Muscle glycogen
       • 400 g (1600 kcal)
   • Glycogen
     • Importance of glycogen
     • Muscle glycogen depletion during exercise
     • Key to endurance performance
       • Carb depleted
         • Can't maintain workload
         • Lower plasma glucose
         • Lower plasma lactate
         • Higher FA oxidation
   • Glucose
     • Falls after 1 hour endurance exercise
     • Production by liver
       • Glycogenolysis
         • Major backup source for blood glucose
           • Increases with exercise time
           • Increases with intensity
         • Uses metabolic byproducts
       • Increases with intensity
       • Gluconeogenesis
     • Glucose uptake increases with intensity

2. Fat

   • Fuel sources
     • Plasma fatty acid
       • From adipose tissue
       • Decreased usage with intensity
     • IMTG
       • Increases, then decreases with intensity
   • Rely more on stored fat during low-intensity exercise
   • Types
     • Simple Lipids
       • Triglycerides
         • Glycerol + 3 Fatty acids Storage form of lipids
       • Hydrophobic
       • Lipolysis
         • Breakdown of triglycerides into glycerol + 3 FA
     • Compound Lipids
       • Lipids + other molecules
       • Phospholipids
         • Lipid + phosphate Cell membranes
       • Glycolipids
         • Lipid + carbohydrates Antibody identification, cell function
       • Lipoproteins
         • Lipid + protein Makes lipids water-soluble Major form of lipid transport in blood
         • Chylomicrons
           • Packaged triglycerides from diet     
         • HDL
           • “good cholesterol” ~50% is protein (providing greater density)     
         • LDL
           • “bad cholesterol” ~25% is protein (ie. reduced density compared to HDL)     
         • VLDL
           • Mostly triglyceride inside Made (ie. packaged) in the liver     
     • Derived Lipids
   • Fatty acid structure
     • Chains of carbon
       • usually 12-20 carbons long     
       • # of carbons and hydrogens determine properties
       • Saturated
         • Hydrogen attached to all possible binding sites of the Carbon atoms  “saturated with Hydrogen” No double bonds between Carbon atoms Animal fat, eggs, & dairySolid at room temp     
       • Unsaturated
         • One or more double bond Can synthesize through hydrogenation
         • Monounsaturated
           • One double bond Olive oil, canola oil
         • Polyunsaturated
           • >1 double bond safflower, sunflower, soybean, corn oils
           • Trans
           • Cis
   • Relative health risk
   • Rely more on fat with endurance duration

3. Protein

   • Structure
     • Amino acid chains
       • R groups
   • Metabolism
     • Anabolism
     • Catabolism
     • Glucose-alanine cycle