Athletic Performance and Protein IntakeProtein BasicsSlide 3Protein SynthesisDietary Protein RequirementsProtein and AthletesProtein Needs in AthletesMeeting dietary protein needs in Athletes...Slide 9Strength AthletesSlide 11Slide 12Slide 13Slide 14Slide 15Protein Intake and Protein SynthesisSlide 17Muscle growth, fat lossProtein SourcesSlide 20WheySlide 22What is whey anyway?Why could whey be better than other protein sources?Slide 25Athletic Performance and Protein IntakeProtein Basics•Proteins are molecules have many enzymatic and structural functions related to the growth, maintenance and repair. –The goal of dietary protein intake is to contribute the amino acids necessary to assimilate proteins for skeletal structures and hormones, function as cell membrane receptors and maintain fluid balance.H2N - C - CHOHORAminecarboxylProtein needs are estimated by measuring nitrogen balance...Nitrogen balance= in (protein intake) – out (sweat, urine and feces)Protein Turnover 200g-400g dailyProtein Degradation: catabolismProtein Synthesis: anabolismThese two mechanisms employ different pathways. Both pathways are always “on”. Nitrogen balance reflects the net protein degradation or synthesis at the whole body level.Protein Synthesis•For athletes in training their goal is to maintain or increase lean body mass (FFM)–An increase in muscle size and thus mass is caused by an increase in protein synthesis.•Increased protein synthesis is reflected by an positive nitrogen balance... Anabolic environment.–Muscle mass maintenance (endurance athletes) is sustained by discouraging protein degradation.•Protein degradation is reflected in a negative nitrogen balance... Catabolic environment.Dietary Protein Requirements•The RDA for protein in normal sedentary individuals is 0.8g/kgBW (1kg=2.2lbs)–For a 130lbs person=(130/2.2)*0.8 = 47g–For a 180lbs person=(180/2.2)*0.8 = 65g•Athletes have increased protein needs compared to sedentary people but there is some debate about how much protein athletes really need...Protein and Athletes•General belief:–Endurance performance = CHO intake–Strength/Power performance = protein intake•But this is not true. All athletes have an increased need over sedentary people for dietary protein.–Goal of endurance athletes: provide amino acids for energy , maintain FFM–Goal of resistance athletes: gain/maintain FFMProtein Needs in Athletes•Endurance Athletes:–Protein oxidation occurs as an energy source–After prolonged or high intensity exercise a negative net protein balance is seen–Training seems to have a protein sparing effect, protein oxidation during exercise decreases with training•Recommendations, agreed upon by most researchers:–1.2-1.8g/kgBW •For 130lbs person (1.5g/kgBW)= 88g•For 180lbs person (1.5g/kgBW)= 122gMeeting dietary protein needs in Athletes...•Endurance:–Ex: Tour de France. Athletes have difficulty maintaining energy balance but are in nitrogen balance. Research has shown a linear relationship between energy intake and protein intake. When they consumed 12% protein of 6500kcal, easily met requirements.When energy intake matches output in endurance exercise athletes don’t need to supplement with extra protein.Protein Needs in Athletes•Resistance Training/Strength Athletes: numerous research studies but no clarity about how much “extra” protein a strength athlete needs.•The goal of the resistance trained athlete is to increase FFM (must be in positive protein balance after exercise, promote muscle synthesis)–The general consensus is that a general increase in dietary protein intake will promote muscle growthStrength Athletes•Research has shown:–Tarnopolsky et al. recommended that athletes involved in high intensity sports & resistance training consume 1.76g/kg/BW of protein to maintain a positive nitrogen balance. •130lb person = 104g•180lb person = 144g–They also showed that 1.0g/kgBW maintained nitrogen balance while 2.77g/kgBW attained a positive balance that was twice that of the lower group.•Also evidence that body-builders require only 0.82g/kgBW to maintain balance...•Surprisingly one study found that athletes couldn’t maintain nitrogen balance with an intake of 2.0g/kgBW.Conflicting results in dietary protein recommendations are due to problems with methods used and intensity of the training.•Lemon et al. adds to the body of literature suggesting that strength and power athletes need between 1.5-2.0g/kgBWEvidence has shown:–protein needs in strength athletes increase with changes in intensity and volume to their training–This need for “extra” protein is negated after 12 days of training. (temporary in response to a training stimulus)–With further increases in training loads, protein requirements are also increasing to promote synthesis.Meeting dietary protein needs in Athletes...•If athletes consume 15% of their calories as protein are they getting enough to promote an increase in FFM?–Let’s do the math for a male involved in a moderate intensity resistance training program (160lbs=72.7kg):PROTEIN CONSUMED:TDEE = 3000kcal15% of 3000kcal= 450kcal/4kcal/gPRO = 112g PRO = 112/72.7 = 1.45 g/kg BW/dayMeeting dietary protein needs in Athletes...•What about 20%?3000kcal *20%= 569kcal/4kcal/gPRO=140g PRO = 1.9 g/kg/dayIs simply increasing dietary protein intake sufficient to maintain or increase FFM?After exercise the environment of the body is catabolic (favors protein breakdown).•Feeding promotes protein synthesis:1) Increases amino acid pool2) Elevated plasma insulin reduces protein breakdownWhat should I eat?A mixed meal is recommended with at least 1g of CHO/kg BW and 0.5g PRO/kg BW after an intense training session.180lbs (81.8kg) = 82g CHO and 41g PROProtein Intake and Protein SynthesisRasmussen et al. (2000)–After a bout of resistance exercise subjects were fed 6g of a.a. plus 35g sucrose–Plasma a.a. increased 3-fold, insulin increased 10-fold–Muscle protein synthesis was increased 3.5 fold. There was no increase in breakdown.–Control condition saw a net protein breakdown.•The effect of timing...–If feeding is delayed by 24hours net protein balance is negative and no muscle hypertrophy occurs. •Order of CHO and protein in post-exercise meal...should CHO precede protein?–Shifting environment to the “fed” state by ingesting CHO first may limit the oxidation of absorbed amino acids–Trade-off is that the stimulatory