Dietary Goals and Carbohydrates Quiz

Dietary Goals

• Optimize Performance & Body Composition by consuming appropriate nutrients.
• Acceptable Macronutrient Distribution Ranges (AMDR) are set by the Food and Nutrition Board to guide dietary choices.

Carbohydrates

• Primary Role: Energy provision providing 4 kcals per gram.
• Simple Carbohydrates (Monosaccharides & Disaccharides):
  • Monosaccharides: Glucose, Fructose, Galactose
  • Disaccharides: Sucrose, Lactose, Maltose
• Complex Carbohydrates (Polysaccharides):
  • Polysaccharides: Starch, Fiber, Glycogen
• Simple Carbs: Digested rapidly causing a large insulin response, potentially leading to fat deposition if glycogen stores are full.
  • Optimal Consumption: When glycogen stores are depleted.
• Fiber (25g-38g/day): Important for digestive health, helping to prevent heart disease, diverticulosis, colon cancer, and type 2 diabetes.
  • Weight Loss: Fiber contributes to satiety, promoting fullness between meals.

Carbohydrate Requirements For Optimal Performance

• Minimum: 50-100g per day to prevent ketosis and catabolism.
• Strength/Sprint/Skill Athletes: 5-6 g/kg/day
• Endurance Athletes (>90 min/day): 8-10 g/kg/day

Fat

• Essential for Life: Temperature regulation, organ protection, insulation, vitamin distribution, energy production, cell membrane formation (omega-3, -6).
• AMDR: 20-35% of energy from fat (400-700 kcals or 44g-77g based on 2000 kcal diet).
• Diets < 15% Fat: Potentially lack health benefits and are difficult to sustain.

Fat Types and Effects on Cholesterol

• Monounsaturated: Olives, olive oil, canola oil, peanut oil, almonds, peanuts. Lowers LDL, raises HDL.
• Polyunsaturated: Corn, soybean, safflower, fish oils. Lowers LDL, raises HDL.
• Saturated: Whole milk, butter, cheese, ice cream, red meat, coconuts. Raises LDL and HDL.
• Trans Fatty Acids: Margarine, shortening, fried foods. Raises LDL, lowers HDL.

Fat Metabolism During Exercise

• Epinephrine: Stimulates breakdown of adipose tissue triglycerides (TG), releasing free fatty acids (FFA) into the blood.
• Low Intensity Exercise (< 25% VO2 max): Less than 20% energy from CHO, over 80% from fat.
• Moderate to High Intensity Exercise:
  • 65% VO2 max: Fats & CHO contribute equally.

  • 85% VO2 max: Fat contribution diminishes (< 25%), muscle glycogen becomes the preferred energy source.

Fat Metabolism Factors

• Fitness level
• Exercise type
• Intensity and duration
• Fat reserves
• Ability to mobilize and transport FA
• Pre-exercise meal composition
• Availability of stored CHO or CHO intake during exercise

High Fat Diets and Performance

• Single High Fat Meal (4 hr prior): No significant impact on performance.
• Short-Moderate Term High Fat Diets (3-5 days to 4 weeks): May benefit steady-state, moderate intensity exercise, improving fat oxidation and in some cases time to exhaustion.
• High Fat Diets Followed by High CHO Intake (short or long term): Short term followed by CHO intake appears to be beneficial for performance.
• High Fat Diets and High Intensity Activity: Not practical due to potential GI distress and the metabolic characteristics of fats.

Protein

• Composition: Composed of amino acids (AAs)
• Essential AAs: 9 AAs the body cannot synthesize.
• Functions: Oxygen transport (hemoglobin), immune support (antibodies), catalysis (enzymes), muscle contraction (actin, myosin, troponin), blood clotting (prothrombin), hormone signaling, protein synthesis.
• Incomplete Proteins: Food sources deficient in essential AAs. Grains, beans, vegetables.
  • Complete Proteins: Soy and quinoa.
• Complementary Proteins: Combining grains, beans and vegetables to create complete protein sources.
• Protein Quality: Measured using the Protein Digestibility Corrected Amino Acid Score (PDCAAS).

Protein Requirements

• Sedentary Individuals: 0.8 g/kg/day for cell turnover.
• Endurance Athletes: 1.2-2.0 g/kg/day for tissue repair and BCAA use.
• Strength/Power Athletes: 1.4-2.0 g/kg/day for tissue repair and anabolism.

Factors Influencing Protein Requirements

• Total energy intake
• Weight loss/gain goals
• Carbohydrate availability
• Exercise intensity and duration
• Dietary protein quality

Proteins and Exercise

• Minor Energy Source: Protein contributes relatively little energy during exercise.
• Prolonged Endurance Exercise: Protein may contribute up to 15% of energy cost.
• High Intensity Exercise & Protein Synthesis: Brief sessions of high intensity exercise lower protein synthesis rates and accelerate breakdown.
  • Carbohydrate Consumption: May mitigate this effect.

Too Much Protein?

• Potential Risks:
  • Renal Damage: Less likely in healthy individuals.
  • Increased Urinary Calcium Excretion: May only be a concern for those using purified protein supplements rather than food.
  • Dehydration: Increased water loss due to nitrogen excretion.

Vitamins & Minerals

• Vitamins: Organic compounds not synthesized by the body.
  • Fat-soluble: A, D, E, K (absorption aided by fat).
  • Water-soluble: C and B vitamins.
• Minerals: Inorganic elements essential for growth and metabolic processes.
  • Calcium: Muscle contraction and bone mineralization.
  • Iron: Oxygen transport.

Vitamin Importance

• B Vitamins: Support energy production and muscle building/repair.
• Vitamin D: Crucial for calcium absorption and bone health.
• Antioxidants (Vitamins C & E, β-carotene, Selenium): Protect cells from oxidative damage.

CHO Pre- and Post- Training

• Pre-Training (1-4 hrs prior): 1-4g/kg bodyweight.
• Post-Workout: 1-1.5 g CHO/kg bodyweight at frequent intervals (every 2 hours).
• Glycogen Synthesis: Initiating with CHO+PRO intake demonstrates significant improvements in glycogen resynthesis rates.

Combining CHO + PRO

• Increased Protein Synthesis: CHO intake with protein significantly boosted protein synthesis and reduced muscle tissue damage.
• Enhanced Glycogen Storage: Simultaneous CHO+PRO intake resulted in superior glycogen storage compared to CHO-only or isocaloric treatments.

Do You Need To Fuel/Hydrate During Exercise?

• Recommended for Exercise > 60 Minutes.