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Protein Requirements for Athletes…
Beyond Daily Targets
Gary Slater PhD
Senior Lecturer (Masters of Sports Nutrition)
University of the Sunshine Coast
National Performance Nutrition Coordinator ARU
Overview of Session
• Factors to consider…
– Energy budget
– Protein distribution
– Protein dose
– Protein source
• Amino acid profile
• Digestion rate
• Intake during exercise
• Health implications
Protein Requirements
Group
Protein Intake (g.kg-1.day-1)
Male Female
Sedentary males & females 0.8 - 1.0 0.8 - 1.0
Recreational endurance athletesa 0.8 - 1.0 0.8 - 1.0
Moderate intensity endurance athletesb 1.2 1.0
Elite male endurance athlete 1.6 1.4
Resistance athletes (early training) 1.5 - 1.7 1.3 - 1.5
Resistance athletes (steady state) 1.0 - 1.2 1.0
Football, power sports 1.4 - 1.7 1.2 - 1.5 aExercising 4-5.wk-1 for 30 min. @ < 55% VO2 peak
bExercising ~ 4-5.wk-1 for 45 – 60 min.
Clinical Sports Nutrition (4th ed.) 2010.
Muscle Protein Turnover
Little & Phillips. Appl Physiol Nutr Metab. 34:817-826, 2009.
Mu
scle
Pro
tein
Ba
lan
ce
I
II
AA/Leucine
± CHO
AA/Leucine
± CHO
Fed state gains (I) = Fasted state losses (II)
Muscle Protein Turnover
Little & Phillips. Appl Physiol Nutr Metab. 34:817-826, 2009.
Fed state gains (I+III) > Fasted state losses (II-IV)
AA/Leucine
± CHO
AA/Leucine
± CHO
Mu
scle
Pro
tein
Ba
lan
ce
Resistance Exercise
I
II
III
IV
Muscle Protein Turnover
Phillips et al. Am J Physiol 273:E99-E107, 1997.
Protein Synthesis
Protein Breakdown
Rather than the age-old debate regarding overall protein & amino acid needs of athletes, focus should be given to the importance of timing & type of protein & amino acid ingestion relative to both muscle
growth & exercise performance. Recent data indicate that consuming a small meal of mixed macronutrient composition following strength exercise bouts can alter significantly net protein
balance, resulting in greater gains in both muscle mass & strength than observed with training alone. With aerobic exercise, some evidence suggests immediate post-exercise supplementation is also beneficial. Second, protein type may also be important owing to variable speeds of absorption &
availability, differences in amino acid and peptide profiles, unique hormonal response, or positive effects on antioxidant defence. In addition to athletes, many others who desire to regain, maintain, or
enhance muscle mass or function need to ensure that nutrient availability is sufficient during the apparently critical anabolic window of time associated with exercise training sessions.
Lemon et al. Curr Sports Med Rep. 4:214-21, 2002.
Lemon et al. Curr Sports Med Rep. 4:214-21, 2002.
• When reviewing protein needs of athletes, consider desired outcomes as well as…
– Total energy intake
– Distribution of protein intake
– Individual protein dose
– Protein source
Overview of Session
• Factors to consider…
– Energy budget
– Protein distribution
– Protein dose
– Protein source
• Amino acid profile
• Digestion rate
• Intake during exercise
• Health implications
Protein Requirements
• Optimisation warranted for wide range of athletes & specific goals – Strength, endurance
– Fat loss, muscle gain, optimal recovery
• When assessing protein intake, consideration must be given to… – Training undertaken & desired outcomes
– Energy budget (& thus co-ingestion of other nutrients)
– Distribution of protein throughout the day • Include a small serve at each meal & snack
– Individual doses of protein at meals & snacks • 15-30g+ (0.3g·kg-1) for majority of athletes, slightly higher for older athletes
• Upwards of 50g if satiety is priority
– Source of protein • Rapidly digested HBV proteins rich in Leucine should be a priority • Emphasize nutritious protein rich foods, achieving overall nutrient needs • If using protein supplements, allocate use to periods where you’ll get
‘maximum bang for your buck’ & limit to <1-2 serves a day
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