Ch 9 Basic Nutrition

Basic Nutrition Factors in Health

  • Presented by: Boram Lim, Ph.D., NSCA CSCS, ACSM EP

Role of Sports Nutrition Professionals

  • Sports nutrition is NOT a “one-size-fits-all” discipline.

  • Diverse nutritional goals for athletes include:

    • Increasing energy.

    • Building muscle.

    • Losing weight (fat).

    • Healing injuries.

    • Speeding recovery.

    • Most competitive athletes seek nutritional strategies to improve performance.

  • Varying degrees of nutrition knowledge among athletes:

    • Athletes with complex nutrition issues should be referred to a team physician or sports dietitian.

    • A sports dietitian is a registered dietitian with specific education and experience in sports nutrition.

    • They may hold a Board Certified Specialist in Sports Dietetics (CSSD) certification.

  • Responsibilities of registered dietitians in sports nutrition include:

    • Translating the latest scientific evidence into practical recommendations.

    • Assessing and analyzing:

    1. Dietary practices.

    2. Body composition.

    3. Energy balance of athletes.

    • Developing personalized meal and snack plans to achieve both short- and long-term goals for performance and health.

  • Key Point: Experienced sports dietitians help athletes understand the connection between their nutrition (plate) and their performance.

    • They possess advanced knowledge, skills, and expertise in the field of sports nutrition.

Standard Nutrition Guidelines

  • MyPlate is a food guidance system developed to assist consumers in making better food choices, serving as a baseline starting point.

    • Recommendations may need adjustments for those physically active for more than 30 minutes most days.

Healthy Eating Plate

  • Healthy oils (e.g., olive, canola) should be used for:

    • Cooking.

    • On salads.

    • At the table.

    • Limit butter; avoid trans fats.

  • Vegetables:

    • Increase variety and quantities; avoid potatoes and French fries.

  • Whole Grains:

    • Include whole grains such as whole-wheat bread, whole-grain pasta, and brown rice.

    • Limit refined grains (white rice, white bread).

  • Fruits:

    • Consume a wide variety of fruits of all colors.

  • Healthy Protein:

    • Choose fish, poultry, beans, and nuts.

    • Limit red meat and cheese; avoid processed meats (e.g., bacon, cold cuts).

  • Water:

    • Drink water, tea, or coffee (minimal sugar).

    • Limit milk/dairy to 1-2 servings/day and juice to 1 small glass/day; avoid sugary drinks.

  • Physical Activity:

    • Stay active!

MyPlate Recommendations Table (Table 9.1)

  • Estimated Daily Calories based on activity level:

    • Children (2-3 years): 1,000 calories;

    • Fruit: 1 cup

    • Vegetables: 1 cup

    • Grains: 3 oz. equivalents

    • Protein: 2 oz. equivalents

    • Dairy: 2 cups (1.5)

    • Oils: 3 tsp

    • Ages 4-8: 1,200-1,400 calories

    • Girls (9-13): 1,600 calories;

    • Fruit: 1-1.5 cups

    • Vegetables: 1.5 cups

    • Grains: 2 cups

    • Protein: 5 oz. equivalents

    • Dairy: 3 cups (3)

    • Oils: 4 tsp

    • Ages 14-18: 1,800 calories

    • Boys (9-13): 1,800 calories

    • Ages 14-18: 2,200 calories

    • Females (19-30): 2,000 calories

    • Adjust for age and activity level.

MyPlate Vegetable Subgroup Recommendations (Table 9.2)

  • Weekly Amounts for different age groups:

    • Children (2-3 years): 1/2 cup red/dark green, 2.5 cups orange, 0.5 cup beans/peas, 2 cups starchy, Other: 1.5 cups.

    • Females (19-30 years): 1.5 cups red/dark green, 5.5 cups orange, etc.

    • Recommendations help in achieving overall intake.

Dietary Reference Intakes (DRIs)

  • The DRI for each nutrient includes:

    • A total of 50 nutrients among which are 14 vitamins, 18 minerals, and 18 macronutrients.

  • Categories of DRIs include:

    • Recommended Dietary Allowance (RDA): Average daily nutrient requirement for most healthy individuals.

    • Adequate Intake (AI): Level suggested when an RDA cannot be established.

    • Tolerable Upper-Level Intake (UL): Maximum daily intake that poses no health risk.

    • Estimated Average Requirement (EAR): Average daily intake to meet needs in 50% of healthy populations.

Key Terms in Nutrition

  • Recommended Dietary Allowance (RDA): The average daily nutrient requirement for most healthy individuals at different life stages and sexes.

  • Adequate Intake (AI): Recommended nutrient intake when RDA cannot be determined.

  • Tolerable Upper-Level Intake (UL): Highest daily nutrient intake with low risk of adverse effects; excess increases risk.

  • Estimated Average Requirement (EAR): Daily intake sufficient for the needs of half of the healthy population.

Macronutrients

  • Definition: Nutrients required in significant amounts in the diet.

  • Three Important Classes of Macronutrients:

    1. Protein

    2. Carbohydrate

    3. Fat

    4. Alcohol

Protein

  • Types of Amino Acids:

    • Essential Amino Acids (9): Cannot be synthesized by the body; must be obtained through diet.

    • Non-Essential Amino Acids (4): Can be synthesized by the body.

    • Conditionally Essential Amino Acids (7): Needed in certain circumstances.

  • Protein Digestibility: Assessed by nitrogen absorption during digestion and the ability to provide necessary amino acids.

  • Protein Requirements:

    • RDA for adults: 0.8extg/kg0.8 ext{ g/kg} (approximately 0.36extg/pound0.36 ext{ g/pound}) for both sexes.

    • Common recommendation: 10-15% of total calories.

Acceptable Macronutrient Distribution Range (AMDR)

  • For protein: 10% to 35% of total calorie intake.

  • Concerns:

    • Higher protein intake may be needed for bone health.

    • Excessive protein may lead to compromised CHO and fat intake.

    • High intake could cause conditions like Gout.

Athlete Protein Intake

  • Athletes require higher protein than the RDA for muscle repair and growth.

  • Recommended intake ranges from 1.0extto1.7extg/kg1.0 ext{ to } 1.7 ext{ g/kg} body weight, for example:

    • For an 80 kg athlete: 80extgextto136extg80 ext{ g} ext{ to } 136 ext{ g} of protein.

Protein Quality

  • Higher-quality proteins are highly digestible and contain all essential amino acids.

  • Plant-based proteins are less digestible; soy protein is the exception, containing all essentials.

  • Muscle Protein Synthesis (MPS): Muscle sensitivity to amino acids persists for up to 48 hours post-exercise.

Carbohydrates

  • Chemical Composition: Comprised of carbon, hydrogen, and oxygen; major fuel source (~ 4extkcal⋅g−14 ext{ kcal·g}^{-1}).

  • Total storage capacity: approximately 2000 kcal (500 g) as glycogen in skeletal muscle.

Types of Carbohydrates

  • Monosaccharides: Single sugar units (e.g., glucose, fructose).

  • Oligosaccharides: Composed of 2-10 monosaccharides.

    • Example disaccharides include:

    • Sucrose: Glucose + fructose (table sugar).

    • Lactose: Glucose + galactose (milk).

    • Maltose: Glucose + glucose (used in brewing).

  • Polysaccharides: Long chains of monosaccharides; examples:

    • Starch: (e.g., rice, bread).

    • Fiber: (e.g., broccoli, kale).

    • Glycogen (energy storage).

Glycemic Index (GI)

  • Definition: Classifies food based on blood glucose impact.

    • High GI foods increase blood glucose quickly.

    • Low GI foods lead to slower rises in blood glucose.

Glycemic Index Food Examples (Table 9.5)

  • Low GI (55 or less): Apple juice, carrots, chocolate, etc.

  • Medium GI (55-69): Brown rice, couscous, honey, etc.

  • High GI (70 or more): Cornflakes, glucose, instant mashed potatoes.

Carbohydrate Requirements for Athletes

  • Endurance athletes require high carbohydrate replenishment:

    • Recommended intake: 8 to 10 g/kg BW.

    • Example: A 70 kg endurance runner would need approximately 560g to 700g/day.

Implications of Dietary Changes

  • Key Point: Athletes adapt over time to carbohydrate intake changes.

    • Low-carb diets may shift reliance on fat for energy (LCHF & Keto diets).

Fat

  • Structure and Function of Lipids:

    • Saturated Fats: No double bonds.

    • Monounsaturated Fats: One double bond.

    • Polyunsaturated Fats: Two or more double bonds (e.g., omega-3 & omega-6).

  • Fats provide approximately 9 kcal/g.

Relationship with Cholesterol

  • High levels of total cholesterol, LDL, and triglycerides increase heart disease risk.

  • High HDL levels are protective; can be increased through exercise and weight loss.

Fat Intake Recommendations

  • Limit saturated fat to 10% or less of total calories.

  • Suggested sources include:

    • Olive oil, avocados, nuts, etc.

Performance and Fat as Fuel

  • Body hosts sufficient fat reserves for extended activity.

  • Consistent aerobic training enhances fat utilization as energy.

  • Energy shifts from fat to carbohydrates during higher intensity exercises.

Vitamins

  • Definition: Organic compounds needed in small amounts; essential for various metabolic functions.

Minerals

  • Essential for diverse metabolic functions vital for athletes, such as:

    • Bone health.

    • Oxygen transport.

    • Electrolyte balance.

Key Minerals and Their Importance

  • Iron: Necessary for hemoglobin; widely deficient, especially in women and children.

  • Calcium: Low intake risks osteopenia and osteoporosis in athletes.

Fluid and Electrolytes

  • Fluid Balance: Water comprises 45% to 75% of the body's mass, influenced by fat-free mass and fat mass.

  • Adequate Intake (AI) for men: 3.7 L/day; for women: 2.7 L/day.

Preventing Dehydration

  • Athletes must avoid losing more than 2% of body mass during activity.

  • Fluid loss translates to approximately 16 ounces per pound lost.

Key Point: Hyponatremia

  • Risk for athletes who hydrate with only water during intense prolonged exercise, diluting blood sodium levels dangerously low.

Fluid Intake Guidelines

  • Start hydrated before exercise; consider individual hydration needs.

    • Recommendations for children, adolescents, and adults vary:

    • Children: 5 ounces every 20 minutes.

    • Adolescents: 9 ounces every 20 minutes.

    • Adults: Individual hydration plans suggested.

Sweat Rate Calculation

  • Formula:
    extSweatRate=rac(extpre−exerciseBM−extpost−exerciseBM+extfluidintake−exturinevolume)extexercisetimeinhoursext{Sweat Rate} = rac{( ext{pre-exercise BM} - ext{post-exercise BM} + ext{fluid intake} - ext{urine volume})}{ ext{exercise time in hours}}

    • Example Calculation: Pre-exercise BM 61.7 kg, Post-exercise BM 60.3 kg, Fluid intake 420 ml, Urine volume 90 ml, Exercise time 90 minutes (1.5 hours).

  • Results in sweat loss of approximately 1,730 ml and a sweat rate of 1,153 ml/h.

Conclusion and Recommendations

  • Athletes should establish and regularly evaluate their hydration strategies to optimize performance and health outcomes.

  • Developing personalized plans that account for individual sweat rates, physical activity levels, and nutrient needs is crucial for effective sports nutrition.

  • Monitoring and adapting to nutritional strategies can greatly improve athletic performance and health management.