Dietary
Recommendation for
Athletes
Dr. David L. Gee
FCSN/PE 446
Training Diet Recommendations:
High Carbohydrate Diet
 For
“Power Athletes”
 Traditional
recommendation
– > 55% of calories
 Why?
– primary source of energy
– effect of repeated high intensity
workouts on glycogen
Training Diet Recommendations:
High Carbohydrate Diet
 For
“Endurance Athletes”
 Traditional
recommendation
– > 60% of calories
 Why?
– endurance training reduces glycogen
– repeated training effects
ADA/ACSM Position Paper
Dietary Carbohydrates

6-10 gCHO/kg BW
– Upper end with high intensity
– Upper end with long duration


Recommends against % CHO guidelines
4000 Cal/day @ 50%CHO for 70kg athlete
– = 7.1 gCHO/kg

2000 Cal/day @ 60%CHO for 60kg athlete
– = 5 gCHO/kg
Training Diet Recommendations:
High Carbohydrate Diet
 Recovery

Meal
CHO ingested within 2hrs of workout is
converted to glycogen 50% more rapidly.
– Rec: up to 1.5 g CHO/kgBW of mixed CHO within
2 hours (hi glycemic index?)
– Particularly important for multiple
workouts/events per day

Role for protein in recovery meal?
Training Diet Recommendations:
High Carbohydrate Diet: Recovery Meal

Example:
–
–

Whole/real foods preferred
–

50 kg x 1.5 gCHO/kg = 75gCHO
= 5 servings of bread or fruit
Cheapest, has other nutrients
Sport Supplements
–
–
–
Convenient
Concentrated
Expensive
High CHO Energy Drinks
Energy Bars
> 70% carbohydrate calories
Sport Shakes
Energy Gels
Training Diet Recommendations:
Moderate Protein Diet

RDA = 0.8 gP/kgBW
 For




“Power Athletes”
ACSM/ADA:
– 1.6-1.7gP/kgBW
maintenance of large muscle mass
optimizes rate of protein synthesis
(?)
Is more protein a problem?
Training Diet Recommendations:
Moderate Protein Diet
For “Endurance
Athletes”
 ACSM/ADA:

– 1.2-1.4gP/kgBW

replaces proteins used as
fuel during endurance
training (10-15% of
energy)
Training Diet Recommendations:
Moderate Protein Diet
 Most
athletes do NOT need to
consume supplementary
amounts of protein
 typical
US diet: 15% of calories
 4000 Cal diet = 150g Pro in the diet
 90 kg “Power athlete” needing
1.6gP/kg = needs 144g Pro
Which athletes are at risk for
inadequate protein intake?

Limited caloric intake
– low meat/dairy intake
– very low fat intake
– weight conscious athlete
2000 Calorie, 10% protein
 = 200 PRO Cal = 50g PRO provided
 1.6 gPRO x 55 kg = 88g PRO needed

MetRx Protein Plus Powder




INGREDIENTS: METAMYOSYN®
(Unique Blend of Milk Protein
Concentrate, Calcium Caseinate, Sodium
Caseinate, Whey Protein Isolate, LGlutamine, Dried Egg Whites), Natural
and Artificial Flavors, Partially
Hydrogenated Oil (soybean and
cottonseed oils), Aspartame, Sodium
Carboxymethylcellulose, Guar Gum,
Xanthan Gum.
$40/container, 16 servings/container,
46gP/serving = $2.50/serving,
$75/month, $900/year
8 oz sirloin steak, $5/lb, 56gP, $2.50
5 c NF milk, $2/gal, 40gP, $0.63
Training Diet
Recommendations:Low Fat Diet
 >55-60%
<
CHO, 10-15% PRO
25% FAT
 Advantages
of moderately low fat
(compared to very low fat)
– High caloric density
– Wider variety of foods available
– May be more palatable
Training Diet Recommendations:
Summary

Carbohydrates
– Moderate to high in carbohydrates
» 6-10g CHO/kg BW

Protein
– Higher than RDA, moderately high
– Power athletes: 1.6-1.7gP/kgBW
– Endurance athletes: 1.2-1.4gP/kgBW

Fat
– Balance of calories, relatively low fat
– <25% of calories
Case Study: Brian
Competitive Stair Runner

Works 7AM to 3:30PM
– Construction contractor in Boston suburbs

Training Schedule
– 5X/week for 2 hours on stairs
» 3 hour RT commute to city
– Trains weekends by cycling/trail runs

Diet
– Realizes he needs hi CHO diet
– Eats convenience foods
Brian’s Diet and Training Schedule







6:30AM: lg bowl cereal, banana, whole milk
7AM: coffee w/cream&sugar, doughnut
12noon: spaghetti with butter, 1-2 slices
bread w/butter, 4 Oreo cookies, 2c whole
milk
4-5:30PM: drives to Boston
5:30-7:30PM: trains
7:30-9PM: 16 oz sport drink while driving
home
10PM: mac & cheese (frozen dinner), handful
of crackers, 2 c milk, 4 Oreos, or a fast-food
burger, fries, 2c milk
Brian’s Diet Analysis



4000 Cal, 50% CHO, 15% PRO, 35% Fat
Assume 160 lbs = 73kg
PRO needs = 1.4gPRO/kg x 73 = 102gPRO
– PRO intake = 4000 x 15% = 600 Cal PRO
» = 150 g PRO, protein intake is OK
» Or 150g/73kg = 2.1 gP/kgBW

CHO intake = 4000 x 50% = 2000 Cal CHO
» = 500 g CHO
» = 6.8 g CHO/kg
» CHO intake OK, but perhaps marginal

Goal:
– Increase CHO, decrease FAT intake
– Recognize need for convenience
Case Study: Weight Gain for a
Professional Basketball Player
 25
yo CBA rookie
 7’1” (2.2m)
 215 lbs (98kg)
– BMI = 20
– Goal weight 235 lbs
24 hour diet recall
PRO: 97g/98kg=1.0gP/kg
CHO: 1011g/98=10.3g/kg
Diet analysis of 24-hr recall
Revised food list
PRO: 174g/98kg = 1.8gP/kg
CHO: 782g/98kg = 8.0gP/kg
Revised diet analysis
Pre-Event Meal
Goals
 “Top
off” glycogen stores
 Optimize hydration
Empty
upper GI tract
Pre-Event Meal
Meal
 High
Composition
in carbohydrates
– mixed
complex and simple
 Reasonably
low in fats and
protein
 Low in dietary fiber
Pre-Event Meal
Composition
(cont.)
 High
in fluids
 Individualize
–Use familiar foods
Pre-Event Meal
Timing
of meal
–Complete > 2 hours before
event
 Individualize
Carbohydrates Just Prior to
Event
Purpose: provide exogeneous CHO to
avoid hypoglycemia and delay
glycogen depletion.
 For endurance athletes only

– Absorption delayed
Response highly individualized
 Caution:

– May promote reactive hypoglycemia in
sensitive individuals
Meals/CHO before/during/after events

Pre-event/Pre-game meal
– 2-3 hours before event

CHO immediately prior to event
– 5-15 minutes before event
CHO during event
 Post-workout meal

– Within 2 hours of workout
Carbohydrates During Event
Sport drinks, energy bars, fruits, breads
 Metabolically useful for

– endurance athletes
» May spare muscle/liver glycogen
» May provide extra CHO for more power
– those prone to hypoglycemia
» Exogenous source of glucose for blood

Dilute concentration (<10%) may be
advantageous because it also promotes
fluid absorption
Types of Carbohydrate

Fructose
– Absorbed more slowly than glucose
» Reduced insulin response
» Reduced chance of reactive hypoglycemia

May produce more stable blood sugar if consumed
45 minutes prior to exercise
» May cause osmotic diarrhea in susceptible
individuals in high dosages
– Free fructose, high fructose corn syrup
(~50%), sucrose
Types of Carbohydrate

Glucose Polymers
– Short polymers of glucose
» Partial hydrolysis of starch
– Soluble, low osmolarity, rapid gastric
emptying, digestion, and absorption
– Most, but not all studies, suggest that
glucose polymers may be superior to
glucose, fructose, and sucrose
Types of Carbohydrate

Solid vs Liquid Carbohydrates
– Most studies suggests little difference
between solid vs liquid carbohydrates
» Those that show difference tend to suggest that
liquids are more rapidly absorbed
– Ultra-endurance athletes may develop
aversion to liquid sweet carbohydrates
Types of Carbohydrate

Low Glycemic Index Food
– Slowly absorbed resulting in lower, but
prolonged elevation of blood glucose
– Research findings vary when comparing
hi-, mod-, and low- GI foods and
performance
Types of Carbohydrate

Individualize type of carbohydrate used
– Individual differences
– Sport differences
– Use before/during workouts
» Note outcomes
Carbohydrate Loading
 Theory:
Glycogen depletion is a cause of fatigue
in endurance athletes.
 Increasing glycogen stores above
normal levels will enhance performance
in endurance athletes.

Diet, muscle glycogen, and endurance
performance.
Karlson & Saltin. J. Appl. Physiol. 1971-31:203-206.




Subjects: Trained distance runners
Protocol: normal vs high carb diet
Performance test: 30km run
Outcomes:
– Muscle glycogen after hi-carb diet was double that
than after normal diet
– All runners finished 30km faster after hi-carb diet
by an average of 8 minutes
– No benefit seen in first hour of run, but able to
maintain pace toward end of run.
Carbohydrate Loading Protocol:
Classic Method
 Depletion
Phase (3-4 days)
– Strenuous endurance training
– Very low carbohydrate diet
 Repletion
Phase (3-4 days)
– Tapered training --> rest
– Very high carbohydrate diet
» 8-10g CHO/kg
Carbohydrate Loading Protocol:
Classic Method: Drawbacks
High level of fatigue during depletion
phase
 May result in hypoglycemia and
ketoacidosis during depletion phase
(nausea, fatigue, dizziness, irritability)
 Very unusual diet during depletion
phase

– Unappetizing
– May cause GI distress
Carbohydrate Loading Protocol:
Classic Method: Drawbacks

May not result in substantially higher
glycogen levels than Modified Method
– Effect of different dietary CHO plans and muscle
glycogen content (Sharman, 1981)
» Protocol: trained runners, 73% VO2max for 90, 40, 40, 20,
20, 0 minutes
– Muscle glycogen content
» 50% CHO diet for 6 days: 160 mmol/kg
» 50% CHO for 3 days, 70% CHO for 3 days: 203 mmol/kg
» 15% CHO for 3 days, 70% CHO for 3 days: 207 mmol/kg
Carbohydrate Loading Protocol:
Modified Method

Mild Depletion Phase
– Normal training with tapering
– Moderate carbohydrate diet (~4gCHO/kg BW)

Repletion Phase
– Light training --> rest
– Very high CHO diet
» 8-10gCHO/kg BW
» 400-700gCHO/day
» 70-80% of total Calories
Carbohydrate Loading

Diet a mixture of complex and simple
carbohydrates to maximize liver and muscle
glycogen

Effect of Dietary CHO-type on Rate of Glycogen
Synthesis (Costill, 1981)
– Protocol: trained endurance athletes, 10 mile run @ 80%
VO2max + five 1-minute sprints with 3 minute rests
– Muscle glycogen content
» 24 hours


High simple CHO diet: 133 mmol/kg
High complex CHO diet: 138 mmol/kg
» 48 hours


High simple CHO diet: 145 mmol/kg
High complex CHO diet: 165 mmol/kg
Carbohydrate Loading

Concerns:
– 2-3 lbs of weight gain (water)
» 3 grams of water for every extra gram of glycogen stored


»
»
300-400 grams of glycogen = 900-1200 grams of water
1.2-1.6kg weight gain (2.5-3.5 pounds)
stiffness
hyper-hydration
– nausea and diarrhea with diet changes
– Useful ONLY FOR ENDURANCE ATHLETES!
(events over 60 minutes)