Consent Form Received.
The Role of Milk in a Dietary Strategy to Increase Muscle Mass and Improve
Recovery: Case Study of an Elite Sprint Kayaker
Dr Karen Reid, Ph.D, Registered Dietitian
Member of the UK Sport and Exercise Nutrition Register (SENr)
Director Performance Food Ltd. PO Box 58, Swansea SA3 4WX, UK.
E-mail: [email protected]
Website: www.performancefood.co.uk
The author is the Director of Performance Food Ltd and undertook the work described in this
case study as part of her consultancy work with Performance Food Ltd.
The athlete has read, approved, and provided written permission for this case study to be
submitted for the Dairy Council Awards.
KEY WORDS
Sports nutrition, kayaking, recovery, milk, protein, muscle mass
ABSTRACT
Flatwater kayaking requires upper-body muscle strength and a lean body composition. This
case study describes a nutrition intervention with a 19 year-old male elite Sprint Kayaker to
increase muscle mass. Prior to the intervention daily energy intake was 3247 kcal (protein 1.8
g/kg, carbohydrate 3.6 g/kg) and the athlete was unable to eat sufficient food to meet the energy
demands of training. During the intervention the athlete’s daily energy intake increased to 5279
kcal (protein 3.2 g/kg, carbohydrate 7.7 g/kg) by including milk based drinks pre and posttraining and before bed. This simple dietary intervention, along with a structured strength and
conditioning programme, resulted in an increase of 10 kg body mass without any significant
change in body fat. In addition the athlete reported the milk based drinks were easy to consume,
and for the first time, was able to maintain weight during intensive phases of the training cycle.
INTRODUCTION
The case study is a 19 year-old male Sprint Kayaker racing over K200, K500 and K1000
distances and member of the British Canoe Union (BCU) Olympic Development Programme
(ODP) and National under 23 training squad based at Teddington. As Kayaking is a sport which
requires upper-body muscle strength and a lean body composition (Michael et al. 2008) the
athlete’s aim was to focus on his physical development and increase muscle mass and strength.
He was set a target by his Great Britain (GB) sprint coach to increase body mass to 85 kg by
January 2014 and 90 kg by January 2015.
DESCRIPTION AND RATIONALE
The athlete was referred for nutrition support in January 2013 by his strength and conditioning
coach who was concerned that he was fatigued and not recovering well between training
sessions. At that time he was a member of the GB Junior Development squad, ranked 5th in
the UK in his age group and weighed 78 kg. A further consideration was the athlete required
surgery on his wrist during September 2013 and underwent a 6 week rehabilitation period
before resuming his weight training in November 2013.
Consent Form Received.
An initial assessment of nutritional intake and energy requirements was performed along with
body composition analysis and a blood test to measure Vitamin D status. A nutrition
intervention was developed to support the athlete’s training goals. An important focus was to
ensure day-to-day energy needs were being met and a positive energy balance for growth and
development of muscle mass. A further goal for the athlete was to maintain weight during
intensive training phases such as overseas training camps and during racing regattas as he had
previously lost the muscle mass gained from winter weight training.
Post-exercise nutrition was considered a priority for the athlete to improve recovery and
optimise muscle protein synthesis. Studies have demonstrated that protein ingestion postexercise increases the rate of muscle protein synthesis and suppresses muscle protein
breakdown (Phillips et al. 2005). Moore et al. (2009) concluded the optimum protein intake
for promoting net muscle protein gain was 20 g; therefore 20-25 g protein with carbohydrate
was advised post-exercise.
Whole milk ingestion post-exercise has been shown to enhance muscle protein synthesis and
gains in fat free mass. Evidence suggests that dairy proteins (casein, whey) are most effective
in stimulating muscle protein synthesis (Tipton et al. 2004). Whey protein has also been found
to enhance muscle protein synthesis rates over casein due to differences in digestion and
absorption kinetics affecting the uptake of amino acids into muscle (Wilkinson et al. 2007). A
further study (Cockburn et al. 2008) compared semi-skimmed milk and a flavoured milk drink
with a sports drink or water after eccentric exercise. Results showed improved recovery from
the muscle damaging exercise in those who consumed both the milk and flavoured milk drink
but not for those who consumed the sports drink or water. Notably, milk has a naturally high
electrolyte content which has been shown to aid fluid retention and have added benefits postexercise as a rehydration drink. Other studies have also suggested that consumption of low fat
milk post-exercise was more effective than water or a 6% carbohydrate electrolyte drink at
restoring and maintaining hydration (Shirreffs et al. 2007; Watson et al. 2008).
CASE PRESENTATION
The athlete lives with his parents in Maidstone (Kent) and studying for A Levels. He trains
twice each day with one rest day (Sunday) and also attends GB under 23 training sessions at
Dornay, Teddington and Bisham which involves staying in a shared house with the London
based Kayakers and preparing his own food.
Table 1 describes a typical training and school day routine.
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Table 1 Typical Daily Food Intake and Training Activity Pre-intervention
Activity
Food or Drink
5:30 am: 1st Breakfast
80g Porridge oats, half pint milk, 200 ml
orange juice, water
6.00 -7.00 am: Paddle
Maximum pace, 30 stroke every 2x10x2
7.30 am: 2nd Breakfast
2 scrambled eggs, 2 slices toast, cream
cheese, 200 ml orange juice
8.30 am: School
1.00 pm: Lunchbox at school
Pasta salad, ham, mascarpone, peppers, basil,
tomato, olive oil
3.50pm: Pre-training snack
Ready-made quiche (200 g)
6.00-7.00 pm: Strength training
8.00 pm: Dinner
Chicken portion, apricot and coriander cous
cous
10.00 pm: Bed
Dietary Assessment
In order to assess energy and nutrient intake the athlete was asked to complete a food and fluid
diary over a 7-day period and instructed to estimate portion sizes using standard household
measures, and where possible, information on food labels to record amounts consumed. The
athlete also recorded training sessions undertaken over the same 7 day period. On completion
of the diary the athlete was contacted by telephone to ask about any foods such as snacks and
drinks which may have been forgotten and to clarify preparation methods. The food records
were then analysed using dietary-analysis software (Compeat Pro, Nutrition Systems, UK).
The athlete’s average daily energy intake pre-intervention was 3247 kcal (Table 2) and when
compared with the Reference Nutrient Intake (RNI) for his age and activity level an energy
deficit of approximately 300 kcal per day was noted. Furthermore his average carbohydrate
intake was just 3.6 g/kg and below recommended levels of 5-7 g/kg (IOC, 2010).
Baseline assessments are shown in Table 2.
Anthropometry
The athlete attended the High Performance Sports clinic at University of Kent for physiological
and anthropometrical testing. Body composition was assessed using skinfold calipers
(Harpenden, UK) at 7 sites by the same operator, a qualified sport and exercise scientist.
Results are shown in Tables 2 and 5.
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Table 2 Baseline Anthropometric and Nutritional Assessment of the Athlete
Athlete characteristic
Age (years)
Height (m)
Body mass (kg)
Body mass index (kg/m2)
Body fat (%)
Energy intake (kcal)
Reference Nutrient Intake (RNI)
Serum vitamin D (nmol/L)
Value
18
1.93
78.0
20.9
5.8
3247
3540
120
(70-200 nmol/L replete)
Overview of the Nutritional Intervention
A planned approach to recovery within 30 minutes of each training session was developed to
ensure replenishment of glycogen stores and a sufficient quantity and quality of protein to
stimulate muscle protein synthesis. Flavoured milk was recommended because it provided a
source of high-quality dairy proteins (whey and casein) along with carbohydrate, minerals and
electrolytes to help replenish muscle glycogen and restore hydration. A bespoke homemade
recovery shake was designed consisting of 1 pint of semi-skimmed milk, 50g skimmed milk
powder and 50g of a commercial milkshake flavour (Nesquik, Nestle UK) which is fortified
with iron, magnesium, calcium, phosphorus, B vitamins and vitamins A, C and D. The
milkshake flavour also provided additional carbohydrate to that naturally present in milk. The
nutritional composition of the homemade recovery shake is shown in Table 3.
The athlete also had access to Maxiraw and Maxifuel nutritional supplements via the
GlaxoSmithKline (GSK) partnership with the BCU. In accordance with UK anti-doping
guidelines (UKAD, 2013) it was confirmed that these products were batch tested and registered
with Informed Sport. Their nutritional composition was evaluated in relation to the athlete’s
nutritional requirements and compared with the homemade recovery shake (Table 3). Other
factors such as cost and the convenience of using a commercial product, for example during
overseas training camps and racing regattas were discussed with the athlete.
Whilst the Maxiraw whey protein provided 22 g protein per 25 g scoop, there were insufficient
calories (92 kcal), carbohydrate (0.5 g) and electrolytes (70 mg sodium) for recovery when
used alone with water. However, adding a 25 g scoop to milk or a ready-to-drink flavoured
milkshake (Yazoo, Friesland Campina) enhanced the ratio of whey protein to casein and
increased calories, carbohydrate, electrolytes and micronutrients as shown in Table 3.
An alternative product, Maxifuel RecoverMax offered a better balance of protein and
carbohydrate, however nutritional comparisons (shown in Table 3) concluded that 2 servings
would be required to achieve the energy, protein and carbohydrate content of the homemade
recovery shake.
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Table 3 Nutritional Comparison of Commercial Nutritional Supplements (GSK) with a
Homemade Recovery Shake using Milk
Nutrient
Maxiraw
whey protein
per 25 g scoop in
Yazoo flavoured
milk (475ml)
Maxifuel
RecoverMax
(400ml)
per 75g serving
Homemade Recovery
shake
per pint semi-skimmed
milk
Energy (kcal)
377
290
637
Protein (g)
36.3
14.5
39
Carbohydrate(g)
46.0
55
103
Fat (g)
6.0
1.2
11.0
Fibre (g)
N/A
0.7
0
Sodium (mg)
257
90
537
Potassium (mg)
N/A
307
1783
Calcium (mg)
570
125
1346
Magnesium (mg)
N/A
152
143
Phosphorus (mg)
N/A
27
1061
L-Glutamine (g)
N/A
5.0
L-Carnitine (mg)
N/A
1.0
16.0
Zinc (mg)
N/A
N/A
5.0
N/A
N/A
A, C, D and B
Vitamins
* As Glutamic acid
4.1 *
After trialling the options in Table 3 the athlete decided to use the homemade recovery shake
on a day-to-day basis after training and continued to use it during a 3 week overseas training
camp in Seville (March 2014) and at racing regattas.
The 6 am water based training presented a challenge as time was limited for eating a large bowl
of porridge which was bulky and difficult to manage before an intensive training session. A
trial using a breakfast shake made with 1 pint of full fat milk, 50 g skimmed milk powder, 50
g milkshake flavour, 2 bananas and a 36 g sachet of instant porridge providing 1089 kcal, 48 g
protein and 172 g carbohydrate was undertaken. The athlete preferred the convenience of the
shake which he was able to consume during his journey to the river and felt more comfortable
Consent Form Received.
during training. A further benefit was the higher energy, protein and carbohydrate content
compared to porridge.
Table 4 describes the athlete’s typical daily food intake during the intervention.
Table 4 Typical Daily Food Intake and Training Activity during the Intervention
Activity
Food or Drink
5:30 am: 1st Breakfast
Breakfast shake, 2 x 65 ml bottles fermented
milk (Yakult, UK)
200 ml orange juice, water
6.00 -7.00: am Paddle
Maximum pace, 30 stroke every 2x10x2
Homemade recovery shake within 30
minutes
7.30 am: 2nd Breakfast
2 scrambled eggs, 2 slices toast, cream
cheese, 200 ml orange juice
8.30 am: School
Mid-morning snack
Fig roll biscuits or malt loaf, fruit
1.00 pm: Lunchbox at school
Pasta salad with Italian tomato sauce
chicken, spinach
3.50 pm: Pre-training snack
Bowl of cereal, berries, full fat milk
6.00-7.00 pm: Strength training
Homemade recovery shake within 30
minutes
8.00 pm: Dinner
Baked ham risotto with vegetables.
10.00 pm: Bed
Chocolate milkshake
Outcome of the Intervention
The athlete was reviewed on a regular basis to monitor dietary intake and body mass. Results
of the anthropometrical monitoring are shown in Table 5. Contact was maintained during
overseas training camps via email and telephone to address any concerns.
Body mass increased by 10 kg to 88 kg post-surgery over the intervention period (December
2013 to September 2014) without any significant change in body fat %. Fat mass increased to
8.2% post-surgery and decreased to 6.2% on return to training. During a review on 26th June
2014 the athlete was advised to increase energy intake further to reflect a higher resting
metabolic rate and energy requirements associated with his increased muscle mass. This was
achieved by replacing semi-skimmed milk in the homemade shakes with full fat milk. Fat mass
remained stable thereafter at approximately 7% indicating energy intake was appropriate.
Consent Form Received.
Table 5 Anthropometric History of the Athlete during the Intervention Period
Date of review
Body weight
(kg)
Body fat
(%)
11/ 012013
26/11/2013
78.0
78.8
5.8%
8.2%
9/12/2013
27/12/2013
14/01/2014
1/04/2014
7/05/2014
26/06/2014
17/07/2014
26/08/2014
29/09/2014
80.5
82.5
82.5
84.6
85.8
84.6
86.4
87.8
88.0
6.2%
n/a
n/a
n/a
n/a
n/a
7.6%
n/a
7.2%
Training Phase
Baseline assessment
Rehabilitation following wrist
surgery
Weight training
Weight training
Weight training
Seville training camp
Racing regattas
Racing regattas
Racing regattas
Racing regattas
Weight training
The athlete’s average daily energy intake over the intervention increased by 2032 calories to
5279 kcal and average protein and carbohydrate intake to 3.6 and 7.7 g/kg respectively (Table
6).
Table 6 Nutritional Intake before and during the Intervention Period
Nutrient
Pre-Intervention
Intervention
Energy (kcal)
3247
5279
Protein (g)
(g/Kg)
139
1.8
273
3.2
Carbohydrate (g)
g/Kg
282
3.6
671
7.7
Fat (g)
181
185
Sodium (mg)
4094
7035
Potassium (mg)
4750
10113
Calcium (mg)
1438
6013
Magnesium (mg)
373
840
The breakfast shake, homemade recovery shakes and chocolate milk before bed supplied 58%
of energy intake and 52% and 66% of protein and carbohydrate intake respectively, making a
Consent Form Received.
significant contribution to the athlete’s increased nutritional intake. Table 7 presents the
nutritional contribution of milk-based drinks.
Table 7 Contribution of Milk-based Drinks to the Athlete’s total Nutritional Intake
Food
(per serving)
Energy
(kcal)
Protein
(g)
Carbohydrate
(g)
Fat
(g)
Sodium
(mg)
Breakfast shake
1089
48.0
172.0
28.5
607
Recovery shake 1
754
38.0
103.0
24.0
537
Recovery shake 2
754
38.0
103.0
24.0
537
Chocolate milk
(568 ml)
494
17.5
63.0
21.0
295
Total
Total intake (%)
3091
58%
141.5
52%
441
66%
97.5
53%
1976
28%
RESULTS AND CONCLUSION
The athlete gained a total of 10 kg muscle mass over the dietary intervention without any
significant increase in body fat %. His present weight is 88 kg and is now well placed to achieve
his target of 90 kg by January 2015. This is the first time that the athlete has been able to
maintain weight throughout the years training cycle. Prior to the intervention the athlete was
finding it difficult to eat the quantity of food required to meet the high energy demands of his
training programme and the initial dietary assessment indicated a chronic shortfall in energy
intake. This intervention has demonstrated that milk based shakes and drinks provided a simple,
yet effective approach for the athlete to achieve a significant increase in energy and nutritional
intake to support gains in muscle mass and recovery after exercise. Furthermore the athlete
reported that the milk based shakes and drinks were easy to consume around training and
preferred them to the commercial nutritional supplements.
Practitioner Reflections
Although there are a number of other variables to consider in Sprint Kayaking performance
this intervention highlights the importance of maintaining a positive energy balance to support
growth and development of muscle mass, especially during intensive training phases.
Overall, this case study has shown the significant contribution that milk can make when used
in nutrition interventions with athletes and sportspeople to increase and maintain muscle mass.
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References
Cockburn E, Hayes PR, French DN et al. (2008) Acute milk-based protein-CHO
supplementation attenuates exercise-induced muscle damage. Applied Physiology Nutrition
and Metabolism 33(4): 775-783
IOC (International Olympic Committee) (2010) IOC Consensus statement on sports nutrition
2010. Available at: http://www.olympic.org/Documents/Reports/EN/CONSENSUS-FINALv8-en.pdf (accessed 5th September 2013)
Michael JS, Rooney KB, Smith R (2008) Metabolic demands of kayaking: A review. Journal
of Sports Science and Medicine 7:1-7
Moore DR, Robinson MJ, Fry JL et al. (2009) Ingested protein dose response of muscle and
albumin protein synthesis after resistance exercise in young men. The American Journal of
Clinical Nutrition 89:161-168
Phillips SM, Hartman JW, Wilkinson SB (2005) Dietary protein to support anabolism with
resistance exercise in young men. Journal of the American College of Nutrition 24(2):134S139S
Shirreffs SM, Watson P, Maughan RJ (2007) Milk as an effective post-exercise rehydration
drink. British Journal of Nutrition 98: 173-180
Tipton KD, Elliott TA, Cree MG et al. (2004) Ingestion of casein and whey proteins result in
muscle anabolism after resistance exercise. Medicine and Science in Sports and Exercise
36(12):2073-81
UK anti-doping (UKAD) (2013).Supplements and the risks
http://www.ukad.org.uk/athletes/performance/supplements (accessed 5th September 2013)
Watson P, Love TD, Maughan RJ et al. (2008) A comparison of the effects of milk and a
carbohydrate electrolyte drink on the restoration of fluid balance and exercise capacity in a hot,
humid environment. European Journal of Applied Physiology 104: 633-642
Wilkinson SB, Tarnapolksy MA, MacDonald MJ et al. (2007) Consumption of fluid skim milk
promotes greater muscle protein accretion following resistance exercise than an isonitrogenous
and isoenergetic soy protein beverage. American Journal of Clinical Nutrition 85:1031-1040