INTRODUCTION Nutrient Timing: Affect on Exercise...

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Nutrient Timing: Affect on Exercise

Performance, Training Adaptation

and Body Composition

John Ivy, PhD

The University of Texas at Austin

INTRODUCTION

An important determinant of the adaptive response to exercise is the nutritional status of the individual.

While proper nutrition is certainly important in achieving exercise goals, it has become increasingly evident that when one eats can be just as important as what one eats.

That is, the timing of nutrient intervention or “nutrient timing” can have a significant impact on exercise performance, recovery and training adaptation.

In this presentation, the science behind nutrient timing will be discussed as it relates to exercise performance, recovery and training adaptation.

NUTRIENT TIMING

Simply stated, nutrient timing is the delivery of appropriate macronutrients during the time in which the body is primed to use them most effectively.

Nutrient timing as it relates to exercise can be divided into three phases:

energy phase

anabolic phase

adaptation phase

ENERGY PHASE

The energy phase represents the period

immediately prior to and during exercise. It can

be divided into two periods:

Pre-exercise period (the 4 hours before

exercise)

During exercise period

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PRE-EXERCISE

CARBOHYDRATE FEEDING: EFFECT ON ENDURANCE

PERFORMANCE

Experimental Protocol X

N = 8, well-trained cyclists

Exercise: 80% VO2max to exhaustion

Treatments: Provided 45 min before

exercise

1. Water

2. 75 g glucose in solution

Foster, C. et al. Med. Sci. Sport 11: 1-5, 1979.

0 10 20 30 40 50 60

Cyc

ling R

ides

~80%

VO

2m

ax

Water

Glucose (75 g)

Minutes Rode to Fatigue


7.0

6.0

5.0

4.0

3.0

Se

rum

Glu

cose

(m

M)

0 10 20 30 40 50 60

Time (min)

Water (Control)

Glucose

*

*


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Pre-Exercise and Improvement

• Sherman W, et al. Carbohydrate feedings 1 h before exercise improves cycling performance. Am J Clin Nutr. 54(5):866-870,1991.

• Francescato M, Puntel I. Does a pre-exercise carbohydrate feeding improve a 20-km cross-country ski performance? J Sports Med PhysFitness. 46(2):248-248-256, 2006.

• Gleeson M, Maughan R, Greenhaff P. Comparison of the effects of pre-exercise feeding of glucose, glycerol and placebo on endurance and fuel homeostasis in man. Eur J Appl Physiol Occup Physiol. 55(6):645-653, 1986.

• Karamanolis I, Tokmakidis S. Effects of carbohydrate ingestion 15 min before exercise on endurance running capacity. Appl PhysiolNutr Metab. 33:441-449, 2008.

• El-Sayer MS, et al. Carbohydrate ingestion improves endurance performance during a 1 h simulated cycling time trial. J. Sports Sci15:223-230, 1997.

CAFFEINE AS A

ERGOGENIC AID FOR AEROBIC ACTIVITY

Experimental Protocol

N = 9, well-trained cyclists

(2 females, 7 males)

Rode at 80% VO2max until exhaustion on two

separate occasions

Treatments: Provided 60 min before exercise

Decaffeinated coffee (placebo)

Coffee with 330 mg

Costill, D.L., et al. Med. Sci. Sports 10: 155-158, 1978.

100

80

60

40

20

0

Min

ute

s

Caffeine Placebo

18% improvement

Costill, D.L., et al. Med. Sci. Sports 10: 155-158, 1978.

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THE EFFECTIVE AMOUNT OF

CAFFEINE


N = 8, well-trained runners

Treatments: Placebo, 3 mg/kg body wt, 6 mg/kg

body wt, and 9 mg/kg body wt

Supplements were provided 1 hour before

exercise

Exercise: Run to exhaustion at 85% VO2max

Graham, T.E. and L.L. Spriet J. Appl. Physiol. 78: 867-874, 1995.

70

60

50

40

30

20

10

0

Runnin

g T

ime (

min

ute

s)

0 3 mg/kg 6 mg/kg 9 mg/kg

*

*

Graham, T.E. and L.L. Spriet J. Appl. Physiol. 78: 867-874, 1995.

*

Dietary Nitrate

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Functions of Nitric Oxide

• Increase vasodilation and blood flow

• Lowers blood pressure and plasma triglycerides

• Increase muscle glucose uptake

• Enhances efficiency of oxidative phosphorylation

• Alter calcium release kinetics from the SR and reduces ATP turnover rate at actin-myosin crossbridges

Nitric Oxide Production

• Produced by the conversion of arginine to

nitric oxide and citrulline by nitric oxide

synthase

• In the body nitrate is converted to nitrite,

which in turn is reduced to nitric oxide by

deoxygenated hemoglobin, xanthine oxidase

and other reducing enzymes.

EXPERIMENTAL DESIGN

• Randomized, double-blind, crossover experimental design

• N = 9 club competitive male cyclists

• Investigated the effects of beetroot juice on cycling time trial performance for 4.0 and 16.1 time trials.

• 500 ml of beetroot juice with or without nitrate provided 2.5 h before exercise

• Measure time to complete time trial, power and VO2

Lansley et al. MSSE 43: 1125-1131, 2011.

4 km Cycling Time Trial

Lansley et al. Med Sci Sports & Exerc 43:1125-1131, 2011.

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16.1 km Cycling Time Trial

Lansley et al. Med Sci Sports & Exerc 43:1125-1131, 2011.

CONCLUSION

• Pre-exercise supplementation with 100 g of CHO 30 to

60 min prior to exercise can help performance when

supplementation cannot be done during competition.

• Caffeine in amounts of 3 to 6 mg/kg body wt 45 to 60

min prior to exercise can improve aerobic exercise

performance

• Natural products that are high in nitrate can be

consumed and alter NO levels in the blood

• Increasing nitric oxide availability can reduce the O2 cost

of exercise and improve endurance performance.

SUPPLEMENTATION DURING

EXERCISE

Carbohydrate Supplementation During Steady State Exercise

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6

0

Pla

sma

Glu

cose

(m

M)

Exercise Time (hrs)

5

4

3

2

1 2 3 4

Cycling at 70% VO2max to Exhaustion

6

0

Pla

sma

Glu

cose

(m

M)

Exercise Time (hrs)

CHO5

4

3

2

Placebo

1 2 3 4

Cycling at 70% VO2max to Exhaustion

Carbohydrate Supplementation During Variable Intensity Exercise


• Treatments were 10% CHO supplement and Placebo

• 9 male subjects

• Cycled for 30 min at 45% VO2max, then alternated

between 75 and 45% VO2max for 2.5 hours.

• After 3 hours of cycling, the subjects rode to exhaustion

at 80% VO2max

• Supplements (180 ml) were provided every 20 min over

the first 3 hours of exercise

28

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Min

ute

s

260

240

220

200

40

20

0

Placebo CHO

* 150

125

100

75

50

250 50 100 150 200

Gly

co

ge

n(µ

mo

l/g

ww

)

Time (min)

P

CHO

*

Effect of Carbohydrate/Protein

Supplementation on Exercise Performance

Experimental ProtocolDesign: Double blind, crossover

Treatments: CHO 7.3%

CHO/PRO 7.3%/1.8%

1.8 ml/kg ingested every 15 minutes during

exercise and 10 ml/kg at the end of exercise

Exercise: 75% VO2max until fatigue

15 hours later 85% VO2max until fatigue

Saunders, M.J. et al. MSSE 2004

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Saunders, M.J. et al. 2004

Ride 1

120

100

80

60

40

20

0

Tim

e t

o F

ati

gu

e (

min

)

CHO+PRO

CHO

Ride 2

*

*

*Significantly greater (p<0.05) than CHO Ride.

Low Calorie

Protein/Carbohydrate Supplement with Carbohydrate

being a Mixture of Simple

Sugars

Low CHO/PRO Supplementation

Increases Variable Intensity Exercise Performance

• N = 15

• Randomized double blind repeated measures design

• TREATMENTS

• CHO (6.0%) and CHO (3.0%)/PRO (1.2%) provided as 200 ml/20 min

• PERFORMANCE TEST

• Cycle for 3 hours alternating between 45 and 75% VO2max and then cycled to fatigue at 80% VO2max

McCleave E. et al. J Stren Cond Res 25: 879-888, 2011

CHOCHO CHO+PROCHO+PRO

Kcals 24 16.9

CHO (%) 6 3.0

Dextrose (%) 6 1

Fructose (%) 0 1

Maltodextrin (%) 0 1

PRO (%) 0 1.2

Ratio of CHO: PRO 2.5:1

Treatment Composition

Both treatments contained the equal amounts of Na+, K+, and Mg2+.


SUPPLEMENT COMPOSITION (PER 100 ml)

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Time to Exhaustion

CHO+PRO

CHO

Tim

e t

o E

xhaustion (

min

ute

s)

**

0

10

20

30

40

50

60


15% increase in endurance

CONCLUSION

• Periodic supplementation with CHO/electrolyte drinks

every 15 to 20 min can improve aerobic exercise

performance.

• Using a combination of simple CHO will increase the

rate of CHO assimulation, spare endogenous CHO stores

and improve aerobic exercise performance

• The addition of protein to a CHO/electrolyte sports

drink can limit the need for CHO while also improving

aerobic endurance

ANABOLIC PHASE

The anabolic phase represents the immediate post exercise recovery period.

Post exercise the body is highly responsive to nutrient intervention.

Consuming the appropriate types and amounts of nutrients immediately to 45 minutes after an acute bout of exercise can:

increase rate of rehydration

increase the rate of muscle glycogen storage

reduce muscle damage

increase protein accretion

increase training adaptation

NUTRITIONAL SUPPLEMENTATION

FOR POST EXERCISE RECOVERY

40

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RETENTION OF FLUID

REPLACEMENT

• Exercised subjects in heat until 1.8 L of fluid loss

• 30 min recovery passive recovery

• Replaced 0.9 L of fluid with water or an electrolyte solution

• 45 minutes later replaced final 0.9 L of fluid

• Followed fluid recovery for 2 hours

González-Alonso, Heaps & Coyle, Int. J. Sports Med 13 (1992).

Fate of the Ingested Volume (n=19)

González-Alonso, Heaps & Coyle, Int. J. Sports Med 13 (1992).

Solutions

2.0

W

Flu

id w

eig

ht

(kg

)

CE

1.5

1.0

0.5

0.0

Other Fluid andCarbon Losses

Urine Losses

Volume Retained73 ± 3%65 ± 3%

*

††

EFFECT OF A

CARBOHYDRATE/PROTEIN SUPPLEMENT ON

REHYDRATION

Experimental Design

Subjects exercised to dehydrate by 2.5% of body weight.

Immediately after exercise subjects consumed one of

three liquid supplements equivalent to weight loss:

1. Carbohydrate/protein 6g CHO, 1.75g PRO, 45.8 mg

Na

2. Carbohydrate 6g CHO, 45.8 mg Na

3. Water

Monitored recover for 3 hours

Seifert J et al. IJSNEM 16: 420-429, 2006

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†*

*

C/P CHO Water0

270

280

290

SERUM OSMOLALITY


Se

rum

Osm

ola

lity

mO

sm/k

g

C/P CHO Water0

250

500

750

1000

†*

*

TOTAL URINE OUTPUT


Tota

l Uri

ne

Ou

tpu

t

(ml)

C/P CHO Water0

20

40

60

80

100 *†

*

FLUID RETENTION


% F

luid

Re

ten

tio

n Timing of Supplementation for

Rapid Glycogen Synthesis

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0

5

10

15

201.5g CHO • kg

-1

Immediately Post Exercise

1.5g CHO • kg-1

2 Hours Post Exercise

Gly

co

ge

n S

tora

ge

Po

st

Fe

ed

ing

(µm

ol•

g-1

we

t w

t•

2h

-1)

*

Basal Immediately 2 h Later

Net

Leg

Glu

co

se U

pta

ke

(µg

• m

in-1

• 100cc

-1)

160

140

120

100

80

60

40

20

0

*

Amount of Carbohydrate

Supplementation

0

1

2

3

4

5

6

7

0.0 0.5 1.0 1.5 2.0 2.5 3.0

CHO SUPPLEMENT

g/kg body wt

Provided immediately after and 2h after exercise

GLYCOGEN

SYNTHESIS

(µmol/g/h)

during 4h of

recovery

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Increases Glycogen Storage

with Added Protein

50

Gly

co

ge

n S

tora

ge

(mm

ol/l/4

h)

40

20

10

0

*

CHO-PRO HCHO LCHO

30

55% greater storage

40% greater storage

0

10

20

30

40

50

CHO-PRO HCHO LCHO

Gly

co

gen

Sto

rag

e(µ

mo

l•

L-1

)

180-240 min

40-180 min

20-40 min

0-20 min

Recovery Periods

*Training Adaptation Effects of

CHO/PRO Supplementation Post Exercise:

Timing

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3.5

3

2.5

2

1.5

1

0.5

0

-0.5

-1

-1.5

-2

*

kg

sk

gs

LBMLBM Fat massFat mass

*

Body fat %Body fat %

PRE/POST

MOR/EVE

PRE/POST

MOR/EVE

Cribb & Hayes Med. Sci. Sport Exerc. 38: 1918-1925, 2006

*

µm

2µ

m2

Type-IType-I Type-IIaType-IIa

*

Type-IIxType-IIx

PRE/POST

MOR/EVE

PRE/POST

MOR/EVE

1400

1200

800

600

400

0

200

1000

Muscle Fiber Type


*

kg

sk

gs

Bench pressBench press Squat Squat

*

Dead-liftDead-lift

PRE/POST

MOR/EVE

PRE/POST

MOR/EVE

25

20

15

10

5

0


CHO/Protein Supplementation on

Aerobic Training Adaptation

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% increase, absolute:

• All: 8.3%

• CM: 12.5%

• CHO: 6.5%

• PLA: 6.0%

Maximal Oxygen Consumption

% increase, relative:

• All: 9.1%

• CM: 14.3%

• CHO: 6.4%

• PLA: 6.5%

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

Ch

an

ge in

Ab

so

lute

VO

2m

ax (

L/m

in)

CM CHO PLA

†

SDH

µm

ol/

g/m

in

SDH

µm

ol/

g/m

in

BaselineBaseline EndEnd

10

8

6

4

2

0

Succinate Dehydrogenase

Cit

rate

Syn

tha

se

µm

ol/

g/m

in

Cit

rate

Syn

tha

se

µm

ol/

g/m

in

BaselineBaseline EndEnd

40

30

20

10

0

CMCHO

PLA

Citrate Synthase

50

Muscle Oxidative Capacity

Body Composition Changes

0.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

3500.0

Lean and Fat Mass Differential, Whole Body

Gra

ms

CM

CHO

PLA

*

0.0

500.0

1000.0

1500.0

2000.0

2500.0

Lean and Fat Mass Differential, Trunk

Gra

ms

CM

CHO

A B

C *

0.0

200.0

400.0

600.0

800.0

1000.0

1200.0

Lean and Fat Mass Differential, Legs

Gra

ms

CM

CHO

PLA

+ 1121 g lean mass - (- 1135 g fat mass) = 2256 g

*

whole body differential

Resistance Training Effect of

Carbohydrate/Protein

Supplementation

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Bird et al. (2006) EJAP, 97:225-

238.

32 subjects trained for 12

weeks while consuming

several different nutritional

interventions

Supplements consumed

during exercise

6% CHO solution

6 g EAA

CHO + EAA

Carbohydrate Amino Acid Supplementation Carbohydrate Amino Acid Supplementation

Carbohydrate and Protein Supplementation

What is an optimal amount of protein in a single dose?

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0 10 20 30 40

Protein (g)

Mu

scle

FS

R (

% •

h-1

)

0.15

0.10

0.05

0.00

Moore DR et al., Am J. Clin Nutr 89: 161, 2009.

~8.6g EAA

a

b

b

cc Protein Amount

• 20 g of protein (8.6 g of essential amino acids) maximally stimulates muscle protein synthesis after resistance exercise in young men

Best Type of Protein to Use†

FSR

(%

h-1

)FS

R (

% h

-1)

WheyWhey Soy Soy

*#†

CaseinCasein

Rest

Exercise

Rest

Exercise

.25

.20

.15

.10

.05

0

Tang et al. J Appl Physiol 107:987-992,2009

*#

Whey Protein Produces Best Response

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Re

lati

ve

In

cre

ase

in

MP

S

Hours

Whey

Milk

Soy

Casein

Protein Blend

0 1 2 3 4

Preventing Protein Breakdown

p70S6K

mTOR

�Blood amino acidsInsulin

Protein

�mRNA translation

initiation�ribosomes

4EBP1

eIF2BGSK-3

Akt

mTOR Signaling Pathway

�proteinsynthesis

AMPK

ATP/ADP

�

Glycogen

�

FOXO3A

�proteindegradation

rpS6

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

CTRL WP HMB LEU

0.0

0.2

0.4

0.6

0.8

1.0

CTRL WP HMB LEU

WG

phospho-m

TO

Rser2

448

(Arb

itra

ry u

nits)

a a,b

b

c

CTRL WP HMB LEU

aa

b

c

CTRL WP HMB LEU

b

c

RG

ph

osp

h-m

TO

Rse

r2

43

8

(Arb

ita

ryu

nit

s)

4/17/2013

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0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

CTRL WP HMB LEU

WG

phospho-p

70s6kth

r389

(Arb

itra

ry u

nits)

b

a

CTRL WP HMB LEU

a a

0.0

0.1

0.2

0.3

0.4

0.5

0.6

CTRL WP HMB LEU

RG

phospho-p

70s6k

thr3

89

(Arb

itra

ry u

nits)

a aa

b

CTRL WP HMB LEU

0.0

0.4

0.8

1.2

1.6

2.0

CTRL WP HMB LEU

WG

phosph

o-

FO

XO

3A

se

r31

8/3

21

(Arb

itra

ry u

nits)

aa

a

b

CTRL WP HMB LEU

0.0

0.4

0.8

1.2

1.6

2.0

CTRL WP HMB LEU

RG

phosph

o-

FO

XO

3A

se

r31

8/3

21

(Arb

itra

ry u

nits)

CTRL WP HMB LEU

aa

b

a,b

p70S6K

mTOR

Insulin

�mRNA translation

initiation�ribosomes

4EBP1

eIF2BGSK-3

Akt

mTOR Signaling Pathway

�proteinsynthesis

AMPK

ATP/ADP

�

Glycogen

�

FOXO3A

�proteindegradation

HMB

Leucine

�proteinaccretion

rpS6

CONCLUSION

• The addition of protein to a rehydration supplement will

increase fluid retention and speed rehydration.

• The addition of protein to a CHO recovery supplement

will increase the rate of muscle glycogen replenishment

• A post exercise supplement combining CHO and protein

will enhance protein synthesis post exercise and

increase the rate of training adaptation

• The addition of HMB could possibly reduce protein

breakdown and increase rate of protein accretion

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ADAPTATION PHASE

The adaptation phase represents the 4 to 6

hours after the effects of the initial post-exercise

supplement have dissipated.

During this phase nutrient supplementation

should be intermixed with regular daily meals

and snacks.

Incre

ase i

n M

uscle

Gly

co

gen

Co

ncen

trati

on

(mm

olkg

-1 w

et

weig

ht)

TIME (h)

0

1.40g/kg40

.35 g/kg

2 4 6

20

0

Mu

scle

Pro

tein

Syn

the

sis

(Arb

itra

ry U

nits

Burd, et al. J Appl Physiol 106:1692-16=701, 2009

Rest 3H 24H 48H

Continued Protein Synthesis

High Protein Late Night Snack

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TAKAHASHI, KipnIs, and DAUGHADAY J Clin Invest 47: 2079-2090, 1968.

8PM 12AM 4AM 8AM

Hormone responses

12 normal subjects

Experimental Design

• Subjects (n=20 males) performed a combined

endurance and resistance exercise protocol

starting at 8:00 PM and lasting 2 hours

• Received a CHO/PRO (1:1 ratio) supplement or

Water every 15 min during exercise and a

supplement 15 min and 90 min post exercise

• Whole body and muscle protein synthesis was

determined during exercise, and the subsequent

9 hours of recovery (7 hours of sleep)

Beelen M, et al. J Nutr 138:2198-2204,2008

TABLE 2: Whole-body and mixed muscle protein synthesis rates

following W or C+P ingestion during and after resistance exercise

in healthy young men

W C+P

WB protein synthesis, μmol�kg-1�h-1

During exercise (2 h) 38.7 ± 1.5 49.9 ± 1.9*

During recovery (9 h) 28.6 ± 1.3 34.2 ± 1.4*

Total (11 h) 30.5 ± 1.3 37.1 ± 1.5*

Mixed muscle FSR, %/h

During exercise (2 h) 0.056 ± 0.003 0.083 ± 0.011*

Druing recovery (9h) 0.057 ± 0.004 0.056 ± 0.004*

Total (11 h) 0.057 ± 0.003 0.060 ± 0.003

1Values area means ± SEM, n= 10. *Different from W, P < 0.05.

Baleen M, et al. J Nutr 138:2198-2204, 2008

Experimental Design

• Subjects (n=16 males) performed a resistance

exercise protocol starting at 8:00 PM and lasting 1

hour

• Subjects were provide a CHO(60g)/PRO(20g)

supplement immediately post exercise

• Prior to sleep (11:30 PM) subjects were provided

40g casein or placebo in 450ml water

• Whole body and muscle protein synthesis were

determined for the next 7 hours of sleep

Res et al. MSSE (Published ahead of Print 2012

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[ring-2H5]-Phenylalanine and [ring-2H2]-Tyrosine infusion

Time

Hours

Exercise

Drink

Blood Sample

Muscle Biopsy

1900 2000 2100 2200 2300 000 100 200 300 400 500 600 700

-4.5 -3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5

Sleep

PRO/PLA

Res et al. MSSE (Published ahead of Print 2012)

*

Wh

ole

-bo

dy

pro

tein

kin

eti

cs

µm

olp

he

ny

lala

nin

e �

kg

-1 �

7.5

h-1

Wh

ole

-bo

dy

pro

tein

kin

eti

cs

µm

olp

he

ny

lala

nin

e �

kg

-1 �

7.5

h-1

Breakdown SynthesisBreakdown Synthesis

*

Oxidation Oxidation

Placebo

Protein

Placebo

Protein

350

300

200

150

100

0

50

250

Net Balance


Ove

rnig

ht

mix

ed

mu

sc

le F

SR

(%�� h

-1)

*

0

0.2

0.4

0.6

0.8Placebo

Protein


Importance of Breakfast

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Importance of Breakfast• Cho et al. The Effect of Breakfast Type on Total Daily Energy Intake and Body

Mass Index: Results from the Third National Health and Nutrition

Examination Survey (NHANES III) J Am College Nutr 22:296-302, 2003

“This analysis provides evidence that skipping breakfast is not an

effective way to manage weight. Eating cereal (ready-to-eat or

cooked cereal) or quick breads for breakfast is associated with

significantly lower body mass index compared to skipping

breakfast”

• Ma et al. Association between Eating Patterns and Obesity in a Free-living

US Adult Population Am J Epidemiol 158:85-92f,2003

“Skipping breakfast is associated with increased prevalence of

obesity”

Actions of Sustained Cortisol

• Cortisol actives LPL and increases fat storage

• Will lower growth hormone secretion

• Will inhibit the action of leptin lowering energy

expenditure and increasing appetite

• Somatic consequences of sustained elevation

of cortisol is excess deposit of fat in visceral

adipose tissue and development of insulin

resistance and hypertension

Meal Timing

• Intake in the morning is particularly satiating

• That it can reduce the total amount of energy

ingested during the day

• Intake in the late night lacks satiating value

• Can result in overall greater daily intake

de Castro JM J Nutr 134:104-111, 2004

Experimental Design

• In this study 193 obese (BMI 32.2 ± 1.2kg/m2) sedentary non-diabetic adult men and women (47±7 y of age) were randomized to a low CHO breakfast (LC) or isocaloric diet with high CHO and protein breakfast (HCP).

• Fasting craving scores and breakfast meal challenge assessing hunger, satiety, insulin, ghrelin responses, where performed at baseline, after a diet intervention period (16 wk) and after a follow-up period (32 wk).

Jakubowicz D. et al. Steroids 77:323-331, 2012.

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25

65

70

75

80

85

90

95

0 4 8 12 16 20 24 28 32

HCPb

LCb

Diet Intervention Period

(Week 0 – Week 16)

Follow-up Period

Week 16 – Week 32)

Fig. 2. Body weight by Diet Intervention Group. The p-value is for general linear model repeated

measures comparisons. HCPb = energy-, carbohydrate- and protein-enriched breakfast diet group, LCb

= low carbohydrate breakfast diet group.

Jakubowicz D. et al. Steroids 77:323-332, 2012.

Participant characteristic at baseline and after 16 and 32 weeks,

n=193 LCb group: n=97; HCPb group: n=96

Group Baseline Week 16 Week 32

BREAKFAST MEAL CHALLENGE AUC

Ghrelin AUC240 min pg/ml x 240 min HCPb 259,431 ± 7479 204,325 ± 5579 201,115 ± 7295

LCb 275,432 ± 13,873

280,100 ±

11,735 282,968 ± 9526

p-value <0.24 <0.001 <0.001

Insulin AUC240 min μU/ml x 240 min HCPb 28,564 ± 3543 20,282 ± 3031 14,798 ± 4364

LCb 29,066 ± 3001 18,050 ± 3859 29,816 ± 5863

p-value 0.34 <0.001 <0.001

Hunger AUC240 min HCPb 19,346 ± 2310 19,301 ± 2475 19,890 ± 2204

LCb 35,499 ± 2436 40,651 ± 3264 40,639 ± 3110

p-value <0.001 <0.001 <0.001

Satiety AUC240 min HCPb 41,407 ± 3035 41,047 ± 3683 41,749 ± 2872

LCb 24,955 ± 2736 26,200 ± 6852 25,320 ± 2844

p-value <0.001 <0.001 <0.001

General craving HCPb 48.6 ± 4.7 37.1 ± 12.9 33.2 ± 14.7

LCb 48.5 ± 4.8 58.4 ± 5.7 62.7 ± 6.1

p-value 0.57 <0.001 <0.001

Jakubowicz D. et al. Steroids 77:323-331, 2012

CONCLUSION

• A rapid rate of muscle glycogen and protein synthesis

can be maintained by periodically supplementing post

exercise

• The addition of about 40 g of a slow digesting protein

prior to bedtime can stimulate muscle protein synthesis

while sleeping

• Eating breakfast rapidly lowers cortisol levels that have

been rising during the early morning hours and reduces

the chances of overeating and gaining fat

Planning Meals and Snacks

Around the Workout

4/17/2013

26

Time of day Daily workout schedules

AM Workout PM workout 2x/d workouts

7:00 AM Breakfast Breakfast Breakfast

8:00 AM

9:00 AM Workout Workout

10:00 AM CP Suppl. (2.5:1) CP Suppl. (2.5:1)

11:00 AM

12:00 PM Lunch (CP) Lunch (CP)

1:00 PM Lunch (CP)

2:00 PM

3:00 PM CP snack (1:1) CP snack (1:1)

4:00 PM Workout

5:00 PM Workout CP Suppl. (2.5:1)

6:00 PM Dinner (CP) CP Suppl. (2.5:1)

7:00 PM Dinner (CP)

8:00 PM Dinner (CP)

9:00 PM

10:00 PM CP snack (1:4) CP snack (1:4) CP snack (1:4)

Ratios listed are suggested carbohydrate-to-protein amounts in grams.

SUMMARY

• Supplementation prior to exercise with CHO, caffeine or foods high in nitrates can improve aerobic endurance

• Supplementation with CHO during exercise can improve aerobic endurance and this can be enhanced by using multiple simple carbohydrates and protein

• Supplementation soon after exercise with a CHO/PRO supplement can speed rehydration, glycogen replenishment, protein synthesis and training adaptation

• Supplementing with a small slowly digestible protein can increase protein synthesis during sleep

• Eating a wholesome breakfast will help control caloric consumption throughout the day and reduce the chances of weight gain

INTRODUCTION Nutrient Timing: Affect on Exercise...

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