sports nutrition in the 21 st century – what’s changed since 2000 and where are we going? alan...

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

Alan McCubbinSDA Advanced Sports Dietitian

alan@nextlevelnutrition.com.au

What were the recommendations in 2000?

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):2130-45.

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):2130-45.

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):2130-45.

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):2130-45.

So what’s changed?

Muscle Protein Balance

Waste Products

Oxidation

Gut

Amino Acids & Peptides

Food Animal or Plant based Proteins

When should we eat protein?How much protein should we eat?

What type of protein should we eat?

Protein – When?

Bohé et al. J Appl. Physiol. 2001. 523(2):575-579.

At rest…

Period to “re-set” yet to be studied – estimated ~4-6hrs

“Muscle full effect”

Protein – When?

Res et al. Med. Sci. Sport Exerc. 2012 44(8):1560-1569.

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…

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

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. 2014. 44;71-77.

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):2130-45.

“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.

Fatigue & Regulation of Pacing

TTE Vs TT Results

• 31% reduced TTE in no fluid Vs complete fluid replacement– Walsh RM et al. Int J Sports Med 1994, 15:392–398.

• 25% 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 – 34.

• 1.7% reduced TT (80km) in no fluid Vs complete fluid replacement– Dugas J et al. Eur J Appl Physiol 2009 ; 105 : 69 – 80.

Oral nutrient sensing

Placebo ingestion

Carbohydrate ingestion

Placebo infusion

Carbohydrate infusion

Placebo Mouth Rinse

Carbohydrate Mouth Rinse

57 57.5 58 58.5 59 59.5 60 60.5 61 61.5 62

~1hr TT Performance Time (min)

Int J Sports Med 1997; 18(2): 125-129

Med Sci Sports Exerc. 2004 Sep;36(9):1543-50.

2.3% improvement

No improvement

Med Sci Sports Exerc. 2004 Dec;36(12):2107-11.

2.3% improvement

Menthol9% 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.

CaffeineNo improvement

Doering et al. (2014) Int J Sport Nutr. Exerc. Metab., 24(1), 90–97.

Acetic Acid (Pickle Juice)Reduction in cramp durationMiller et al. (2010) Med. Sci Sports Exerc.,42, 953–961.

Muscle glycogen levelsBlood Glucose LevelBlood sodiumSkin & core temperatureBlood pH

CarbohydrateSodium?Acidity?

Absorption of carbohydrate

G Ga F G G Ga F G

G GG G GG

GGGG

Multiple transportable carbohydrates

Jentjens R et al. (2004) J. Appl. Physiol. 96(4):1277-1284

90g/hr GF mixture

90g/hr Glucose only

Water only

50 52 54 56 58 60 62 64 66 68

~1hr TT Performance Time (min) after 2hr SS

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

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):2130-45.

“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.

Fluid & Hydration

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):2130-45.

“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.

Nutrient Timing

• 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 Others

Carbohydrate

• 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

Supplements

Supplements since 2000

• 2000-2004: Sodium Bicarbonate• 2004-2008: Caffeine, Glycerol, ice slushies• 2008-2012: Beetroot Juice, Beta-alanine• 2012-now: Combinations of supplements

• The ones that never quite made it:– Ribose, Quercetin, L-Carnitine, L-Glutamine, HMB,

others

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, 2nd tier rugby league or below, etc.

• Sources: Powder in a drink (pre-workout formulas, protein powders and

energy drinks)

Energy Drinks

Maximum allowable caffeine = 320mg per litre

Most common sizes250mL cans – 80mg caffeine

470-500mL cans – 160mg caffeine

Is coffee any different?

Desbrow B et al (2012). J Food Comp. and Analysis 2012 28: 114-118.

AIS Sports Supplement Framework

New Tools/Resources

The Quantified Self

So what’s next?

Reverse Dieting

Vs

+ + + = ?

Nutrigenomics

The Quantified Self

What hasn’t changed?

What hasn’t changed?

• 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