9 [Basic Nutrition], 10 [Nutrition Strategy], 11 [Performance Enhancers]

Dietary Reference Intakes (DRIs) (Definition)

A group/set of nutrient references for use when evaluating and planning diets for healthy individuals.

Dietary Reference Intakes (DRIs) (List)

• Recommended Dietary Allowance (RDA): Average daily nutrient requirement of most healthy people in each population

  • Good for individual athletes

• Estimated Average Requirement (EAR): Average daily nutrient requirement of half of healthy people in each population

  • Good for groups of athletes/athletic teams

• Adequate Intake (AI): Average daily nutrient requirement when a RDA cannot be established

  • Good for unestablished nutrients/electrolytes

• Tolerable Upper Intake Level (UL): Maximum average daily nutrient level not associated with any adverse health effects

All populations have a high prevalence of inadequacy of _____ and _____. These can be found in _____

Vitamin E; magnesium

Nuts, seeds, oils

All individuals over the age of 2 have a high prevalence of inadequacy of _____ and _____

fiber; potassium

Individuals over the age of 50 are at risk of _____ deficiency and are encouraged to take synthetic supplements

Vitamin B12

Women and adolescent females capable of becoming pregnant have high prevalence of _____ and _____ deficiency, which can be found in _____

iron; dietary folate

meat, cereal, beans; beans, peas, peanuts, seeds

Amino Acids, Polypeptides, Proteins

Amino Acids: Molecules that form proteins

Polypeptides: Several amino acids together

Protein: Largest aggregate of these constituents, considered one of the macronutrients

Protein Reserves in the Body

• Almost ½ of stored protein exists as skeletal muscle.

• 15% of stored protein is in structural tissue (skin/blood).

• The rest are in visceral tissues (e.g. bones, liver, kidneys).

During cellular turnover, amino acids are released and recycled for use in new cell synthesis. This is not 100% however, indicating the need for dietary protein.

Essential, Nonessential, Conditionally essential amino acids

Essential: The body cannot manufacture them, but needs them

• e.g. animal-based proteins and soy

Nonessential: The body needs them and manufactures them

Conditionally Essential: The body needs them SOMETIMES but cannot manufacture them

Protein Digestibility Correct Amino Acid Score

PDCAAS takes into account essential amino acids AND bioavailability during digestion

Protein RDA

0.80 g protein / kg bodyweight

Protein / Bone Health

Protein makes up 50% of bone volume and 33% of bone mass.

Being under the RDA reduces calcium absorption in the intestines.

Protein / Weight Management

• Promotes satiety in a dose-dependent manner

  • Also depends on timing, form (solid v. liquid), and time until next meal

• Thermic effect (caloric cost of protein metabolism) is greatest compared to other macros

• High protein diets spare muscle loss on a reduced-calorie diet

Protein Requirement: Aerobic endurance, Strength, and Combination athletes

Aerobic: 1.0 - 1.6 g/kg

Strength/Combination: 1.4 - 1.7 g/kg

Post-exercise Protein Intake

Aerobic: 4:1 or 3:1 as carbs:protein

Resistance: 20 - 48 g protein

Excessive Protein Intake Concerns

Proteins consumed in excess of amount needed for synthesis are simply broken down; the nitrogen is converted into urea and the remaining ketoacids are used as energy or converted into carbs (gluconeogenesis).

The consumption of excessive protein on a calorie-restricted diet leave less room for necessary carbs and fats while accomplishing very little for the individual.

Carbohydrate Groups (3)

• Monosaccharides

• Disaccharides

• Polysaccharides

Monosaccharides

e.g. Glucose, fructose, galactose.

Simple single-sugar molecules.

Glucose molecules make up glycogen, a polysaccharide stored in muscle/liver cells.

Disaccharides

e.g. Sucrose, Lactose, Maltose

Two-sugar molecules.

Sucrose: Glucose + Fructose

Lactose: Glucose + Galactose

Maltose: Glucose + Glucose

Polysaccharides

e.g. Starch, Fiber, Glycogen.

Contain up to thousands of sugar molecules, aka complex carbohydrates.

Starch vs Fiber

Both are complex carbs/polysaccharides.

Starch: Storage form of glucose in plants (e.g. grains, legumes, vegetables).

Fiber: Constituent of the plant cell wall (e.g. beans, peas, bran, fruits/veggies, some whole grain foods).

Fiber Functions

There are many different types of fiber with many different functions, including:

• Delayed gastric emptying (→ increased satiety)

• Increasing bulk and water content (→reducing constipation, decreasing transmit time for feces)

• Decrease cholesterol absorption (→reduce blood cholesterol after ingestion)

• Stimulate gut microbiome

Glycogen storage in the body

When glucose enters muscle and liver, but not metabolized for energy, it can be converted into glycogen via glycogenesis.

• ~15 g glycogen / kg bodyweight

• ¾ of all glycogen is stored in skeletal muscle

• ¼ of all glycogen is stored in the liver

Glycemic Index

Ranks carbs according to how quickly they are digested and absorbed (raising blood glucose levels) in the 2-hours post-meal compared to a reference food (white bread or glucose) which has a GI of 100

( (Test food blood glucose response) / (Reference food blood glucose response) ) * 100

Glycemic Load

A more realistic gauge of glycemic response than the GI.

GL = (GI * grams of carbs per serving) / 100

Fiber DRIs

Women: 21-29 g/day

Men: 30-38 g/day

Daily Carb Requirements for Aerobic vs Anaerobic athletes (and post-exercise)

Aerobic: 8 - 10 g/kg bodyweight

Anaerobic: 5 - 6 g/kg bodyweight

Post-exercise: 1.5 g/kg bodyweight of high GI/GL food

Dietary Lipids (Fats) (List)

• Triglycerides (formed by glycerol + 3 fatty acids)

• Fatty acids

• Phospholipids

• Cholesterol

The majority of dietary lipids are triglycerides; in the NSCA exam, fats will refer exclusively to triglycerides.

Saturated vs Unsaturated Fats (Structure)

Saturated: No double bonds and carbon is saturated with hydrogen. Nonessential fat.

Unsaturated: Can be monounsaturated (one double bond) or polyunsaturated (2+ double bonds).

Essential Polyunsaturated Fatty Acid groups

Omega-3 and Omega-6 (both polyunsaturated).

Omega-3: really only in fatty fish and supplements

Omega-6: in an abundance of food like soybean, corn, safflower oils

Omega-3 Fatty Acids

EPA and DHA come from the fish.

ALA comes from seeds/oils and need to convert into EPA/DHA, which is less efficient.

LDL, HDL, and Total Cholesterol (Optimal Ranges)

LDL: <100

HDL: >60

Total: <200

Vitamins vs Minerals

Vitamins: Organic substances typically acting as coenzymes to facilitate reactions in the body

Minerals: Inorganic substances that contribute to structure of bone/teeth/nails, are a component of enzymes, and perform certain metabolic functions

Water-soluble vs Fat-soluble Vitamins

Water-soluble (B/C vitamins): Dissolve in water and are transported in blood, but cannot be stored by the body (except B12). Because of this, it is not believed that excess water-soluble vitamins are harmful because excess becomes urine.

Fat-soluble (all other): Dissolve in fat, are carried by fat in the blood, and can be stored in fat tissue. Excess fat-soluble vitamins are usually harmful because they can build up over time.

Major Minerals (list)

• Calcium

• Phosphorous

• Magnesium

• Iron

• Electrolytes: Sodium, potassium, chloride (magnesium and calcium also count i guess)

Iron Role

Hemoglobin: Carries O2 in blood

Myoglobin: Carries O2 in muscle

Iron Deficiency Risk factors

• Women of childbearing age

• Pregnant women

• Infants/toddlers

• Distance runners

• Vegetarians

• Excessive antacid consumption

• Certain digestive diseases such as celiac disease

Dehydration risk factors

• Children

• Older adults

• Athletes at the beginning of the season

• Sickle cell

• Cystic fibrosis

AI for Water

Men: 3.7 L

Women: 2.7 L

Pregnant Women: 3.0 L

Lactating Women: 3.8 L

*For sport nutrition, this amount PLUS the amount lost to sweat during exercise needs to be consumed

Preventing Dehydration from Exercise

Measure the change in bodyweight from pre- to post- workout.

A loss of 2% of bodyweight is considered bad dehydration.

Each lb lost during practice equals 16 oz of fluid lost.

Sweat Rate Calculation

Bodyweight loss from exercise + fluid intake during exercise - urine volume produced

Pre-exercise Hydration

Prehydrate up to several hours before exercise to allow for fluid absorption and urine output.

• USG <1.020 for athletes

During Exercise Hydration (Children/adolescents)

Children: 5 oz water or a flavored, salted beverage every 20 minutes

Adolescents: 9 oz water or a flavored, salted beverage every 20 minutes

During Exercise Hydration (adults/athletes)

Sports drinks containing

• 20 - 30 mEq sodium / L

• 2 - 5 mEq potassium / L

• 5 - 10% concentration of carbohydrates (multiple types of carbs usually better)

Hydration beverage temperature range

10 - 15 degrees C or 50 - 59 degrees F

Precompetition Meal Guidelines

• Take into account timing, meal competition, and fluid composition

• Smaller quantities of a meal when closer to the event

• Familiar foods to the athlete

• Low in fat and fiber (for rapid gastric emptying, reducing GI distress)

• Moderate in protein (satiety during competition)

Precompetition Meal Timing

• Prehydration as described

• With GI distress potential: 4 hours before competition, 1 - 4 g carbs/kg bodyweight and ¼ g protein /kg bodyweight

• If 2 hours pre-exercise (as with early morning starts): 1 g carb/kg bodyweight, and potentially carb consumption during the exercise to maintain blood glucose

• Remember sports drink during exercise

Traditional Carbohydrate Loading Regimen

1. Tapering exercise 1 week before the event, with complete rest the day before

2. Three-day high carb diet pre-event (8 - 10 g carb/kg) or (10 - 12 g/kg) for marathon runners

Carb Loading: Males vs Females

There is a misconception that men have a greater capacity for carb loading than women. However, this is likely due to study design flaws → because women typically consume less total calories per day than men, they struggle to reach the carb minimum required for effective carb loading. When caloric intake is accounted for/increased in women, they display a similar ability to carb load precompetition.

*>2,400 calories recommended for women during carb loading.

Anaerobic Competition and Carb Loading

Carb loading appears to be less beneficial or not beneficial at all for anaerobic athletes.

Postexercise Protein Consumption

Muscle synthesis post-exercise is highest immediately after (3 hours), and tapers off throughout the 48-hour period.

Ingesting protein immediately after a workout, when muscle synthesis rates are highest, leads to better stimulation of muscle synthesis.

Maximal stimulation occurs with 20 - 25 g of a high-quality, high-leucine, fast protein in younger adults or ~40 g in older adults. The leucine content of the protein, and probably the leucine delivery, appears to be the determining factor for acute changes in maximal stimulation of muscle protein synthesis. Total leucine within the protein should be 2 - 3 g, or 0.05 g / kg bodyweight.

Consistent protein supplementation post-workout leads to mild-moderate increases in muscle hypertrophy compared to none.

Postexercise carbohydrate consumption

Postexercise carb consumption is important for replenishing muscle/liver glycogen stores, especially if there is another competition/training session within the next 24-48 hours. In this case, high GI/GL carbs are best immediately with a mixed carb load otherwise.

Postexercise carb consumption mainly benefits time-to-fatigue, with a very minor effect for performance before fatigue, and little-to-no effect for long-term performance/strength increases.

Protein at mealtime

Resistance training increases muscle sensitivity to amino acids for 24 to 48 hours after exercise; the anabolic effect of a meal lasts 3 - 5 hours.

For optimal muscle remodeling, consume 20 - 30 g protein per meal and eat meals every 3 to 4 hours.

Protein Nutrition: Adults vs Children

Children’s muscle synthesis is driven by insulin and caloric intake, as opposed to leucine in adults. This suggests that children can consume protein in smaller amounts throughout the day to meet protein needs.

Cunningham Equation for RMR

RMR = 550 + 22*(Lean Body Mass)

Wt loss goal in overweight and obese individuals

10% of initial weight lost in first 6 months

Testosterone Efficacy and Adverse Effects

Efficacy: Works to increase lean muscle mass. More effective for trained athletes than untrained individuals.

Risks: Significant health risks to about every system, especially CV, endocrine, and psychological.

Erythropoietin Efficacy and Risks

Efficacy: Helps improve oxygen delivery, improving aerobic capacity and time to exhaustion.

Risks: Blood clotting, strokes, embolisms. Relative dehydration.

B-Adrenergic Agonist Efficacy and Risks

Efficacy: Can increase lean muscle mass and reduce fat mass

Risks: Several reported but not actually documented

Branched-Chain Amino Acids (BCAA)

• Leucine

• Isoleucine

• Valine

All responsible for increasing muscle synthesis; however, leucine appears to be the most important rate-limiter.

Arginine Efficacy and Risks

Efficacy: Purported to increase nitric oxide (and therefore vasodilation), no such evidence has been found.

Risks: No risks found either.

B-Hydroxyl-B-Methylburate (HMB) Efficacy and Risks

Efficacy: Dose-dependent anti-catabolic supplement that reduces muscle breakdown. Most effective under the addition of a novel training stimulus, such as during heavy periodization.

Risks: No risks.

B-Alanine Efficacy and Risks

Efficacy: “Loaded” for 4 weeks and taken continuously. Improves performance in HIIT/anaerobic scenarios (extreme IM acidotic conditions) due to ability to improve H+ clearance.

Risks: Paresthesia only in high acute doses.

Sodium Bicarbonate Efficacy and Risks

Efficacy: Taken acutely 60 - 90 minutes pre-exercise to help acid buffering. Appears to work starting at 0.3 g/kg bodyweight.

Risks: The minimum effective dose (0.3 g/kg) is also the point at which GI irritability begins. Experts recommend trying it during practice/precompetition first.

Sodium Citrate Efficacy and Risks

Efficacy: Similar to sodium bicarb, taken ~.4-.5 g/kg bodyweight.

Risks: GI distress at higher levels (0.6 g/kg bodyweight) than bicarb.

Creatine Efficacy and Risks

Efficacy: Loading phase (~5 days) or non-loading (~30 days) to reach upper ceiling effect. Improves PCr stores by ~20%, improving performance during workouts which leads to better muscle stimulus.

Risks: Only GI distress during a loading phase has been observed long-term.

Caffeine Mechanics, Efficacy, and Risks

Mechanics: Improved beta-oxidation (aerobic) and enhanced excitation-contraction coupling (anaerobic).

Efficacy: Works more for aerobic endurance, results are less clear for power athletes

Risks: Anxiety, GI distress, heart arrythmias, physiological addiction.

Ephedrine Efficacy and Risks

Efficacy: Ephedrine has a synergistic effect with caffeine that is greater than either substance alone for aerobic endurance.

Risks: Banned by FDA and most sports governing bodies due to high GI, neurocardiovascular, and psychological risk