Download Is it in you? Optimal Nutrition for Promoting Aims

10/22/2012
Is it in you?
Optimal Nutrition for Promoting
Physical Activity in Obese Youth
Abbie Smith-Ryan, PhD, CSCS*D, CISSN
Assistant Professor
University of North Carolina Chapel Hill
Aims
• A discussion of nutrient timing
• A detailed look into commonly used sports
drinks: their ingredients, their purpose and
recommendations.
• The role favorite sports drinks may play in
meeting the needs of an overweight
physically active child.
Issues at hand
• Childhood obesity has more than tripled in the
past 30 years.
• This rise follows the increase in SSB’s.
• 84% of teens consume SSB ‘s daily
– Equivalent to +365 extra calories daily
• 50-70% of beverage consumption occurs in
homes. 7-15% occurs in schools
Wang, C et al. Pediatrics 2008.
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Issues at hand
• Sugar consumption:
– Food & snacks = 1˚
– SSB = 2˚
Beverage
(Approximate Calories
per 12oz portion)
Sports drink
105
Energy drink
165
Juice drink
180
Regular soda
Grams of Sugar
140
Phillips, SM. Sports Med 2012: 42 (1): 817-828
Cause of Childhood Obesity?
• Result of the classic weight loss paradigm?
– Too many calories consumed
– Not enough physical activity
• Not the whole picture:
– Type of calories makes a difference:
• Sugar
• Protein
– Type of exercise makes a difference
• EPOC and metabolism
– Nutrient timing
Calorie Balance Equation
• Assumptions include:
– Calorie content of food is accurate
– Calorie expenditure can be measured accurately
– No other factors affect weight management
Biggest influence
Variable
Minor but
advantageous
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Caloric Expenditure & Exercise
Not All Exercise Increases Energy Needs
Baseball/Softball
Track – Field Events & Sprinting
Diving
Any Sport with only 2 activity sessions per week
Sports That Require Additional Energy
Sports training 4 or more times a week HARD
Endurance Sports: swimming, running, cycling
Team Sports: soccer, lacrosse, football, basketball,
lacrosse, ice hockey, field hockey
Gymnastics, tennis, fencing, skiing
Caloric Expenditure & Exercise
• Intensity is the most
important factor
• Nutrient availability
can influence
metabolic response
• Kids (16-30%) > CHO
oxidation than adults
(10-20%)
Caloric Expenditure & Exercise
• Intensity also effects post-exercise caloric
expenditure.
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“Nutrient – Exercise Timing”
Hypothetical Model to Maximize:
Fuel Utilization
Growth
Recovery & Repair
Ivy & Portman 2004; Kerksick et al. ISSN 2008, Manore, Meyer & Thompson 2010
ENERGY
PHASE
ENERGY
PHASE
PreExercise Workout
15-60
min
ANABOLIC
PHASE
PostExercise
1-2
hours
1
hour
GROWTH
PHASE
(Rapid)
GROWTH
PHASE
(Sustained)
Recovery
Recovery
5
hours
16-17
hours
24 Hours
ENERGY
PHASE
PreExercise
15-60
min
•
•
•
•
•
Increase nutrient availability
Spare muscle glycogen
Enhance fat utilization
Minimize muscle damage
Faster recovery provisions
Consume:
- Moderate GI CHO before
- Small Pro- before/during
-Essential AA (e.g., whey)
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ENERGY
PHASE
•
•
•
•
•
Workout
Increase nutrient delivery
Spare muscle glycogen
Limit immune system suppression
Minimize muscle damage
Faster recovery provisions
Consume:
- CHO during exercise
1-2
hours
-Liquid, 6-8% CES
-Small Pro- before/during
-Essential AA (e.g., whey)
ANABOLIC
PHASE
Consume:
- High GI CHO post-exercise, immediate
-Liquid, 6-8% CES
-1.0 to 1.5 g/kg
- Pro- post-exercise
-3:1; 2:1 CHO to Pro- ratio
-Essential AA
- Hydration: 1-2 cups fluid (CES/H2O) per lb lost
High GI CHO – perfect time to feed ‘sweet things’
PostExercise
1
hour
•
•
•
•
•
•
Shift catabolic to anabolic state
Speed waste elimination
Replenish muscle glycogen
Initiate muscle repair-growth
Reduce muscle damage
Bolster immune system
GROWTH
PHASE
(Rapid)
Recovery
5
hours
• Maintain:
• Insulin sensitivity
• Anabolic State
Consume:
- Small CHO / Pro- feedings
-Every 1 to 2 hours post-exercise
-3:1; 2:1 CHO to Pro- ratio
-Essential AA (e.g., whey, casein)
- Food / meals
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Consume:
-Energy intake
-Neutral balance
-Positive N balance
-Pro- intake (1.0-1.5 g/kg/d)
GROWTH
PHASE
(Sustained)
- CHO to repletion glycogen
- Food / meals (mixed diet)
• Maintain + nitrogen bal
• Stimulate protein synthesis
• Promote:
• Protein turnover
• Muscle development
Recovery
16-17
hours
Hydration
Pre-Exercise:
• Young athletes should plan on drinking eight ounces of gatorade sports drink
an hour or two before physical activity.
• About 10 – 20 minutes before the activity, an additional four to eight ounces
should be ingested.
• Why Gatorade?
– Research by Dr. Bar-Or demonstrated in young boys (10-14 years), hydration was
maintained better dinking Gatorade versus plain water and favored water while exercise
in hot environments. Thought to be due to behavior and physiological reasons.
During-Exercise:
• While exercising, young athletes should drink three to four ounces of
CES/water every fifteen minutes
Post-Exercise:
• Young athletes should ingest two cups of water for every pound of weight loss.
Int J Sport Nutr. 1998 Mar;8(1):1-9.
J Appl Physiol. 1999 Jan;86(1):78-84.
Fate of Ingesting 1950 ml Solutions after Exercise
at 2 Hours Post Ingestion
2.5
2
1.5
Other
Urine
Retained
1
0.5
0
W ATER
CHO/ELECTROLYTE
Glucose solution up to 10% without impeding fluid replacement
Glucose greater than 10% will delay gastric emptying and compromise
fluid replacement (Costill 1977)
Gonzalez-Alonso et al. Int J Sports Med. 1992
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Whole Foods or Liquid Supplements – Which is
Better for Exercise Recovery?
• Nutrient timing critical:
– For a rapid and complete recovery due to a metabolic window of
opportunity
• Muscle has residual catabolic activity following exercise, it
will rapidly shift from a catabolic state to an anabolic
state if the right nutrients are ingested soon after
exercise.
– Once the metabolic window of opportunity has closed, nutrient
supplementation is not as effective in shifting the muscles into
an anabolic state
Metabolic window of opportunity – The time after exercise in which the muscle is
highly capable of responding to the anabolic effects of insulin if sufficient substrate is
made available. Without nutrient intervention, the metabolic window begins to close
within 45 minutes following exercise
• Nutrients that are essential for a rapid and complete
recovery are fast-digesting :
– Whey and Casein
– Amino acids
– Electrolytes
– High-glycemic carbohydrates
• Consuming a liquid supplement as your postexercise recovery nutrition helps start the
rehydration process. Whole foods as the recovery
meal will slow gastric emptying and will likely
delay rehydration
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TO DRINK OR NOT TO DRINK?
• Gatorade
– Prime, Perform, Recover
•
•
•
•
•
G2
Powerade
Juice
Soda
Milk
CHO Supplementation in Kids
• Pre-exercise & During CHO supplementation:
Author
Demographics
Protocol
Supplementation Findings
Dougherty
MSSE 2006
Male B-Ball (13.5 yrs)
2h intermittent ex +
B-ball game
6% CES + water; water
– both euhydrated
PshooQng
accuracy (p<0.05)
Carvalho
IJSNEM 2011
Male B-Ball (14.8 yrs)
1.5 hour drills &
training
Ad libitum:
8% CES, water, nothing
No significant
influence of CES on
performance or
shooting accuracy
Phillips
EJAP 2010
M & F multi-sport
(12.7 yrs)
Intermittent
sprinting
6% CES 5ml/kg pre-ex
& 2 ml/kg every 15min
during vs. H2O
24% longer TTE
No effect on sprint
Higher HR in CHO
grp
Phillips
EJAP 2012
M & F multi-sport
(13.3 yrs)
Intermittent
sprinting (4 x 15 min)
2%, 6%, 10% pre and
during
Longer TTE in 6%
vs 10% and 2%.
2%> TTE than 10%
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Concerns – beyond performance
• Dental erosion
– Sports beverages = pH similar to diet cola
• Linked to dental erosion in adult consumers
• Obesity
– Numerous articles citing association of SSB & obesity
– but don’t quantify physical activity
• Mundt et al. MSSE 2006; 38:1245-54– only study to date:
– FM inversely associated with physical activity with no significant
influence of SSB on fat mass.
• Yale Rudd Center for food policy & obesity: SSB synopses
and child obesity: no clear CAUSE, but clear association
• More research is needed.
To drink or not to drink?
• Kool-Aid vs. Milk
– 8 oz Kool-Aid (108 kcal, 28.8 g CHO/sugar)
– 8 oz. 1% milk (102 kcal, 11.7 g CHO, 8 g PRO, 2.6 g
FAT)
FIGURE 1.
•
•
Figure 3.
Figure 5.
REE – indirect calorimetry
Body Fat
• Milk consumption in children
induces greater REE, TEF, and RQ.
– Greater caloric expenditure
– Greater fat utilization
St-Onge et al. Metab Clin Exper 56 (2007) 1699-1707
To drink or not to drink?
• Randomized controlled trial:
– 98 children 8-10yrs regular consuming SSB
• 16-week intervention
– Milk Group: 3 servings/day (1%) & no SSB
– Control: no instruction/dietary changes
• DXA for body composition
– %body fat
– Trunk fat
– Lean mass
• Significant reduction in SSB
– PRO, Calcium increased (p<0.001)
– Calories decreased (p=0.009)
• No change in %Body fat (p=0.22) or Fat mass (p=0.81)
• Significant increase in LBM (p=0.04)
– Greater increase in height for boys
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Summary & Applications
Abbie Smith-Ryan, PhD, CSCS*D, CISSN
[email protected]
919-962-2574
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