Dietary Recommendation

for AthletesDr. 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 DietFor “Endurance Athletes” Traditional recommendation

– > 60% of calories Why?

– endurance training reduces glycogen

– repeated training effects

ADA/ACSM Position PaperDietary 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 DietRecovery 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:– 50 kg x 1.5 gCHO/kg = 75gCHO– = 5 servings of bread or fruit

Whole/real foods preferred– 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 DietMost 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, L-Glutamine, 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/kgCHO: 1011g/98=10.3g/kg

Diet analysis of 24-hr recall

Revised food list

PRO: 174g/98kg = 1.8gP/kgCHO: 782g/98kg = 8.0gP/kg

Revised diet analysis

Pre-Event Meal

Goals“Top off” glycogen storesOptimize hydrationEmpty upper GI tract

Pre-Event Meal

Meal CompositionHigh in carbohydrates

–mixed complex and simpleReasonably low in fats and protein

Low in dietary fiber

Pre-Event Meal

Composition (cont.)High in fluidsIndividualize

–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 LoadingTheory: 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)