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Sports Nutrition in the 21 st Century – What’s changed since 2000 and where are we going? Alan McCubbin SDA Advanced Sports Dietitian

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Presentation on theme: "Sports Nutrition in the 21 st Century – What’s changed since 2000 and where are we going? Alan McCubbin SDA Advanced Sports Dietitian"— Presentation transcript:

1 Sports Nutrition in the 21 st Century – What’s changed since 2000 and where are we going? Alan McCubbin SDA Advanced Sports Dietitian

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6 What were the recommendations in 2000?

7 2000 ACSM Position Statement “Protein requirements are slightly increased in highly active people. Protein recommendations for endurance athletes are 1.2 to 1.4 g/kg body weight per day, whereas those for resistance and strength- trained athletes may be as high as 1.6 to 1.7 g/kg body weight per day.” Med Sci Sports Exerc. (2000) 32(12):

8 2000 ACSM Position Statement “Dehydration decreases exercise performance; thus, adequate fluid before, during, and after exercise is necessary for health and optimal performance. Athletes should drink enough fluid to balance their fluid losses …during exercise 150 to 350 mL (6 to 12 oz) of fluid should be consumed every 15 to 20 min depending on tolerance. After exercise the athlete should drink adequate fluids to replace sweat losses during exercise. The athlete needs to drink at least 450 to 675 mL (16 to 24 oz) of fluid for every pound (0.5 kg) of body weight lost during exercise.” Med Sci Sports Exerc. (2000) 32(12):

9 2000 ACSM Position Statement “Carbohydrates are important to maintain blood- glucose levels during exercise and to replace muscle glycogen. Recommendations for athletes range from 6 to 10 g/kg body weight per day. The amount required depends upon the athlete’s total daily energy expenditure, type of sport performed, sex of the athlete, and environmental conditions” Med Sci Sports Exerc. (2000) 32(12):

10 2000 ACSM Position Statement “During exercise, the primary goals for nutrient consumption are to replace fluid losses and provide carbohydrate (approximately 30 to 60 g per h) for the maintenance of blood glucose levels.” Med Sci Sports Exerc. (2000) 32(12):

11 So what’s changed?

12 Muscle Protein Balance

13 Waste Products Oxidation Gut Amino Acids & Peptides FoodAnimal or Plant based Proteins

14 When should we eat protein? How much protein should we eat? What type of protein should we eat?

15 Protein – When? Bohé et al. J Appl. Physiol (2): At rest… Period to “re-set” yet to be studied – estimated ~4-6hrs “Muscle full effect”

16 Protein – When? Res et al. Med. Sci. Sport Exerc (8): Before bed… Looked at what happens overnight: Weight Training at 2000hrs 20g P, 60g CHO after RT (2100hrs) 40g casein P or placebo 30min before bed (2330hrs) Whole body protein balance measured for 12hrs overnight…

17 Protein – How much? Moore D. et al. Am J Clin Nutr 2009;89:161–8. Young men (at rest or post-RT) ~20-25g or ~0.25g/kg egg protein ~8.5-10g EAA’s

18 Protein – What Type? Protein containing foods have differences in: EAA and Leucine content (HBV proteins have more) Rate of digestion/absorption Phillips SM. Sports Medicine ;71-77.

19 Changes in guidelines “Protein requirements are slightly increased in highly active people. Protein recommendations for endurance athletes are 1.2 to 1.4 g/kg body weight per day, whereas those for resistance and strength-trained athletes may be as high as 1.6 to 1.7 g/kg body weight per day.” Med Sci Sports Exerc. (2000) 32(12): “Our consensus opinion is that leucine, and possibly the other branched- chain amino acids, occupy a position of prominence in stimulating muscle protein synthesis; that protein intakes in the range of 1.3–1.8 g/kg/day consumed as 3–4 isonitrogenous meals will maximize muscle protein synthesis... Elevated protein consumption, as high as 1.8–2.0 g/kg/day depending on the caloric deficit, may be advantageous in preventing lean mass losses during periods of energy restriction to promote fat loss. J. Sports Sci. (2011) 29(Supp 1):S3-4.

20 Fatigue & Regulation of Pacing

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23 TTE Vs TT Results 31% reduced TTE in no fluid Vs complete fluid replacement – Walsh RM et al. Int J Sports Med 1994, 15:392– % reduced TTE in minimal Vs complete fluid replacement – Barr SI et al. Med Sci Sports Exerc 1991, 23:811–817. – Fallowfield JL et al. J Sports Sci 1996, 14:497–502. No difference in 1hr TT in no fluid Vs complete fluid replacement – Bachle et al. J Strength Cond Res 2001 ; 15 : 217 – 24. – Kay D & Marino F. J Therm Biol 2003; 2 8 : 29 – % reduced TT (80km) in no fluid Vs complete fluid replacement – Dugas J et al. Eur J Appl Physiol 2009 ; 105 : 69 – 80.

24 Oral nutrient sensing

25 Int J Sports Med 1997; 18(2): Med Sci Sports Exerc Sep;36(9): % improvement No improvement Med Sci Sports Exerc Dec;36(12): % improvement

26 Menthol 9% increased TTE Mündel & Jones. (2010) European J Appl Physiol, 109(1), 59–65. Bitter Taste (Quinine) ~3% increased power in 30sec sprint Gam et al. (2014) Med. Sci Sports Exerc., 46, 1648–1657. Caffeine No improvement Doering et al. (2014) Int J Sport Nutr. Exerc. Metab., 24(1), 90–97. Acetic Acid (Pickle Juice) Reduction in cramp duration Miller et al. (2010) Med. Sci Sports Exerc.,42, 953–961.

27 Muscle glycogen levels Blood Glucose Level Blood sodium Skin & core temperature Blood pH Carbohydrate Sodium? Acidity?

28 Absorption of carbohydrate

29 G Ga F G G F G G G G G G G G G G G Multiple transportable carbohydrates Jentjens R et al. (2004) J. Appl. Physiol. 96(4):

30 Currell K & Jeukendrup AE. (2008) Med. Sci. Sports Exerc., 40(2), 275–281.

31 Change in guidelines “During exercise, the primary goals for nutrient consumption are to replace fluid losses and provide carbohydrate (approximately 30 to 60 g per h) for the maintenance of blood glucose levels.” Med Sci Sports Exerc. (2000) 32(12): “During sustained high-intensity sports lasting ~1 hr, small amounts of carbohydrate, including even mouth-rinsing, enhance performance via central nervous system effects. While 30–60 g /hr is an appropriate target for sports of longer duration, events >2.5 hr may benefit from higher intakes of up to 90 g/hr. Products containing special blends of different carbohydrates may maximize absorption of carbohydrate at such high rates”. J. Sports Sci. (2011) 29(Supp 1):S17-27.

32 Fluid & Hydration

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35 Change in guidelines “Dehydration decreases exercise performance; thus, adequate fluid before, during, and after exercise is necessary for health and optimal performance. Athletes should drink enough fluid to balance their fluid losses …during exercise 150 to 350 mL (6 to 12 oz) of fluid should be consumed every 15 to 20 min depending on tolerance. After exercise the athlete should drink adequate fluids to replace sweat losses during exercise. The athlete needs to drink at least 450 to 675 mL (16 to 24 oz) of fluid for every pound (0.5 kg) of body weight lost during exercise.” Med Sci Sports Exerc. (2000) 32(12): “Dehydration, if sufficiently severe, can impair performance in most events, particularly in warm and high-altitude environments. Athletes should be well hydrated before exercise and drink sufficient fluid during exercise to limit dehydration to less than about 2% of body mass. Chilled fluids may benefit performance in hot conditions. Athletes should not drink so much that they gain weight during exercise.” J. Sports Sci. (2011) 29(Supp 1):S3-4.

36 Nutrient Timing

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38 Post-training (Cermark et al. Am J Clin Nutr 2012;96:1454–64) Regular serves over the day (Churchward-Venne et al. Amino Acids 2013;45:231–240) Before bed (Res et al. Med. Sci. Sports Exerc. 2012;44,(8):1560–1569) Nutrient timing science in a nutshell Nutrient Timing Protein Ergogenic Aids OthersCarbohydrate Vary glycogen availability to the goals & demands of the session May be some benefit to deliberate restriction Varies: Dose & timing Desired adaptations Iron absorption Calcium & bone health

39 Supplements

40 Supplements since : Sodium Bicarbonate : Caffeine, Glycerol, ice slushies : Beetroot Juice, Beta-alanine 2012-now: Combinations of supplements The ones that never quite made it: – Ribose, Quercetin, L-Carnitine, L-Glutamine, HMB, others

41 Supplements & Doping Positive tests in Australian labs (2012) – 69 from >6,000 tests 40 (58%) were for stimulants Of those who were subsequently banned: – 18 were for Methylhexanamine (DMAA), found in some commercial supplements (Jack3d, White Lightning, OxyElitePro) – it’s listed on the label – 5 were for a substance found in some weight loss supplements The majority of positives were not elite athletes – VFL, state swimming trials, 2 nd tier rugby league or below, etc. Sources: Powder in a drink (pre-workout formulas, protein powders and energy drinks)

42 Energy Drinks Maximum allowable caffeine = 320mg per litre Most common sizes 250mL cans – 80mg caffeine mL cans – 160mg caffeine

43 Is coffee any different? Desbrow B et al (2012). J Food Comp. and Analysis :

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46 AIS Sports Supplement Framework

47 New Tools/Resources

48 The Quantified Self

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50 So what’s next?

51 Reverse Dieting

52 Vs

53 +++= ?

54 Nutrigenomics

55 The Quantified Self

56 What hasn’t changed?

57 Food We eat meals, not nutrients A healthy athlete is a strong/fast/powerful athlete People have their own lives/habits/preferences, and these must be uniquely catered for Nutrition guidelines are a starting point, not a prescription of what to do There are as many similarities as there are differences in different nutrition approaches


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