Overview of Nutrients

Overview of Nutrients

1. Macronutrients

   • carbohydrates (CHO)
     • recommended 60-70% of daily calories
     • 4 kilocalories per gram
     • average person stores 1500-2000 kcals
       • majority is in form of muscle and liver glycogen
       • small portion available as blood glucose
     • loading can benefit athletes in aerobic sports especially if lasting >60 min
     • amount
       • varies directly with exercise intensity and volume
         • easy to moderate/skill based
           • 3-5 g/kg body mass
         • moderate: abt 1 hr/day
           • 5-7 g/kg body mass
         • heavy/endurance: abt 1.5-5 hrs
           • of moderate to high intensity
             • 7-12 g/kg body mass
     • derived from plant sources
       • primarily grains, seeds, fruits, vegetables
     • simple CHO = monosaccharides
       • typically stimulate insulin release and blood glucose fluctuations
       • high carloric
       • often referred to as empty calories
     • complex CHO = polysaccharides
       • whole grain cereals & breads, vegetables, fruit
       • dietary fiber (ingestible CHO)
         • essential for digestion
   • Protein
     • needed for tissue construction, enzyme reactions, and energy during prolonged exercise
     • recommended 12-15% of total daily calories
     • 4 kcal per gram
     • composed of amino acids
       • 20 different ones
       • 8 are essential
         • cannot be synthesized by body
         • must be ingested in diet
     • MYTH: it's #1 energy source
       • only 10% during prolonged activity
     • include eggs, meats, dairy products, legumes, grains
       • vegetarians: must eat foods in correct combination to provide all essential amino acids
         • eat eggs, milk products, or both
     • supplementation
       • during intense training: 1.2-1.8 g/kg body wt. per day
         • 0.83-1.2 g/kg for sedentary or light exercises
       • NO SOLID EVIDENCE that supplementation beyond recommended doses enhances muscles unless you do the work
       • evidence lean muscle is put on easily/quickly
       • caution: it can increase saturated fat in diet AND overstress liver and kidneys
       • ingesting approximately 20g-30g total protein or approx 10 g of essential amino acids during exercise or recovery period
         • led to increased whole body and muscle protein synthesis
         • led to improved nitrogen balance
   • fats (lipids)
     • needed for energy, insulation, and protection of organs
       • recommended 30% or less of total daily calories
         • 0.8-2 g/kg body mass
     • 9 kcal per gram
     • fatty acids and glycerol make up fats
       • fatty acids
         • saturated
           • all of the available bonding sites on molecule are occupied by hydrogen atom
             • derived from animal sources (beef, pork, poultry, and dairy products)
           • generally solid at room temperature
         • unsaturated
           • structures in a way to prevent all the available bonding sites from being occupied by hydrogen
           • plant based
           • generally liquid at room temperature

2. Micronutrients

   • vitamins
     • have various functions
       • regulate biochemical reactions
         • energy metabolism
         • cell and tissue generation
     • contain no caloric value
     • balanced diet supplied RDA or dietary reference intake
     • types
       • water soluable
         • C, B1, B2, B6, B12
         • niacin, folic acid, biotin, pantothenic acid (B5)
       • fat soluable
         • A, D, E, K
   • minerals
     • needed for various body functions
       • provide structure
       • help maintain normal heart rhythm
       • promote neural conductivity
       • regulate metabolism
     • no evidence supporting taking excess minerals
       • but endurance athletes may be at increased risk of iron or calcium deficiency
         • RDAs/RDI iron and calcium
           • iron: 10 mg male; 18-20 mg females
           • calcium: 1200-1500 mg females; 1000-13000 males
   • not eating balanced diet
     • advise inclusion of a vitamin and mineral supplement
       • convenient method: daily multivitamin
       • mega-doses should be avoided and could result in severe consequences and overdosing

3. role of nutrients

   • supply energy
   • regulate various body functions
   • growth and repair of tissue

4. healthy diet = variety is key

   • CHO: 55-70%
   • proteins: 12-15%
   • fats: <30%
   • everyone is UNIQUE and may need adjustments
   • cannot make up for lifetime of bad habits with 1-2 good meals