Rugby Union Pre-Season Nutrition (Part 4): Fat Loss
In the first part of this series we outlined achievable rates of muscle gain and fat loss from which an individual can base goals for the pre-season. If you have not read this then I recommend that you go back and read this prior to continuing with the below. The purpose of this current article is to build upon those initial principles and to outline key components of dietary setup for fat loss. Following this article you should be able to appreciate how daily energy and macronutrient intakes are estimated. Particular focus within this article shall be given to energy intake and protein intake.
Setting daily calorie intake is the foundation from which your dietary setup is based. Once this is determined assignment of the individual amounts of macronutrients (protein, carbohydrate and fat) can be made. As the goal is to decrease fat/body mass a calorie deficit will be required, where energy intake shall be less than energy expenditure. An energy deficit can be created via a restriction in energy intake, an increase in energy expenditure or both. However, if engaging in pre-season training it is important that an appropriate energy deficit is implemented.
The importance of muscle for the rugby athlete has been discussed over the first few parts of this nutrition series. Therefore, implementing a positive energy balance, in combination with strength training, is the most effective strategy to optimise the anabolic stimulus to enhance muscle mass. However, in certain instances muscle can be acquired when within a calorie deficit, whilst also losing fat mass. In fact we highlighted this occurrence in part one, when looking at the body composition of Australian rugby union players during an 11 week pre-season (this may have happened within the other rugby pre-seasons highlighted, but individual data was not reported). With regards to increasing muscle mass within a deficit, this is dependent upon an individuals age, training status, training programme, current body fat %, size of calorie deficit and if they have undergone atrophy due to time off training e.g. injury. Individuals that are resistance trained and of low body fat % may be more concerned with maintaining current muscle mass, or minimising its loss, compared to the gains that can be made by an individual relatively new to resistance training.
Acute vs. Chronic Weight Loss
Often athletes, and in some instance coaches, want results and fast! You may often hear individuals citing high initial amounts of weight loss in the early weeks of their new dietary approach. However, only a few weeks later such progress has slowed or stalled, leading to a decrease in motivation or cessation of diet. Worst case scenario a potential rebound in weight following a frustrated eating binge. It is therefore important to appreciate the difference between acute and chronic weight loss.
Acute Weight Loss
The early rapid weight loss may solely not be attributed to a loss of fat mass. What may occur is the manipulation of body contents similar to typical methods adopted by weight category athletes the week/days prior to competition.
(1) Decreased Carbohydrate Intake: A common strategy is to decrease or remove carbohydrate intake. Restricting intake of this whole food group leads to a decrease in stored carbohydrate (glycogen) within muscle and liver glycogen. For every gram of carbohydrate stored within glycogen around 3 grams of water is bound with it. Therefore, if you have decreased total dietary carbohydrate intake you shall also decrease the amount of water held within glycogen. Interestingly, individuals often opt for a low carbohydrate approach based upon the carbohydrate-insulin obesity model influencing weight gain, but this hypothesis has been falsified (more on this in part six – ‘Nutrition Myths’).
(2) Decreased Salt Intake: Typically individuals will tidy up their nutritional intake and reduce processed and take-away foods. By replacing food choices with added salt, and opting for foods without added salt, your dietary intake will not hold result in as as much fluid retention, as salt aids fluid retention.
(3) Dehydration: Some individuals may not simply be meeting daily hydration needs. Furthermore, an increase in training intensity/volume/frequency will typically elevate fluid requirements due to exercise associated fluid loss e.g. sweat.
(4) Decreased Intestinal Contents: A reduction in food portions or total food volume will reduce the mass of intestinal contents (food within the gut). Some individuals may even turn to ‘meal replacement’ liquid shakes which are low in fibre and therefore provide a lower residue intake. Fibre containing foods slow the transit of food through the bowel, whilst drawing water into the intestinal space.
Chronic Weight Loss
This is the implementation of a consistent dietary approach that brings about a change in total fat and muscle mass over a prolonged period of time. By simply ‘tidying’ up the nutritional quality of your diet you may see greater initial losses of body mass, which may also be beneficial to aid motivation. However, for some after a couple of weeks the scales may not be moving so quickly and this is where motivation may suffer. Worst still some individuals may see weight re-gain following a high carbohydrate or salt containing meal(s). This is where an appreciation of acute and chronic weight change is important. Set realistic body composition progress/goals focused upon chronic change.
Rate of Weight Loss
As discussed above when some individuals set out on their weight loss journey the primary focus may be to see the numbers drop on the scale and fast. However, it is important to consider the quality of weight loss – a decrease in fat mass and maintenance or increase in muscle mass. When opting for a slower weight loss approach (0.7% loss of bodyweight per week), compared to a faster rate (1.4% loss of bodyweight per week), athletic individuals were able to preserve, or in some instances enhance, muscle mass and performance, with greater fat mass loss. Therefore, the greater the caloric deficit the greater the risk of muscle mass loss in athletic individuals.
However, there may be certain instances where a higher rate of weight loss may be required, for example individuals that hold larger amounts of fat mass. In fact, it has been shown that fast initial weight loss enhanced motivation and aided dietary adherence amongst dieters. However, the maintenance or development of muscle mass should also be considered important from a health perspective and not just solely from a performance angle. The greater the amount muscle mass an individual holds the greater the contribution to resting metabolic rate. Furthermore, muscle is a glucose disposal site and for lipid (fat) oxidation. Therefore the individual must opt for an individualised approach when creating their dietary approach.
Daily Energy Intake Calculation
We can estimate calorie intake based upon the utilisation of prediction equations. However, it is important to stress the word ‘PREDICTION’. These equations provide an estimate of energy expended at rest – Basal Metabolic Rate (BMR) or Resting Metabolic Rate (RMR). This is then multiplied by an estimated physical activity level (PAL), incorporating work and physical activity. These estimates are not perfect and have their limitations. However, having said that they can provide an initial ball park figure for calorie intake, from which you can then re-evaluate progress using the tracking methods outlined in the previous article and making energy intake adjustments accordingly.
Three of the most popular popular equations for estimating BMR/RMR include:
(1) Harris and Benedict – incorporates height (cm), weight (kg) and age (years)
(2) Cunningham – incorporates fat-free mass (kg)
(3) Schoefield – incorporates weight (kg) and age (years)
The purpose of such equations has been to predict energy expenditures within the general population, although they have also been used with active and athletic individuals. However, it is important to acknowledge that these equations were not based upon individuals who have large amounts of muscle mass, such as rugby players. Research amongst senior professional rugby league players found that measured RMR was 16.5% (approximately 310kcal) lower than that predicted via the Cunningham equation. Furthermore, Cunningham, Harris-Benedict and Schoefield equations typically underestimated total energy expenditure (TEE) for u16 to u24 rugby league and union players, although an over prediction was seen in some instances, highlighting the great individual variability in predictions.
Research from rugby league has shown the distinctive large energy expenditures of professional academy players during pre-season, highlighting the requirement for equally large energy intake via the diet to aid targeted body composition and physical development. Furthermore, when contact training is integrated within a training programme energy expenditure is elevated due to the collision induced muscle damage. Although from rugby league, such findings can help inform rugby union players due to the collision-based activity within rugby union. It is therefore important that rugby players during pre-season account within their dietary intake for not only the energy expenditure of the work required (e.g. movement demands), but also the muscle damage from contact activity.
It is therefore important to remember the limitations of energy expenditure prediction equations, particularly within athletes. Their use however may give an approximate initial starting point from which this can then be adapted to the individual and re-evaluated based upon progress. As mentioned above to calculate estimated total energy energy expenditure you must first utilise a prediction equation to estimate the energy you expend at rest. This is then multiplied by PAL value that corresponds to your self-estimated activity demands. Below is a table outlining the range of PAL values from which to base estimations.
Although useful, the above can be confusing for individuals when trying to estimate both their expenditure during the day (e.g. job) and training. We are not all professional rugby players and therefore have to consider expenditure at work/school etc. The below table outlines the estimated PAL for differing levels of activity.
A PAL of 1.6 represents the average activity level of a normally active individual, but sedentary for periods. 2.0-2.5 is considered the PAL for athletes engaging in normal training, whereas a PAL of 2.5-4.0 for athletes engaged in rigorous training/competition. In reference to the above PAL guide, a 2.0 PAL was utilised for professional Australian rugby union players during the pre-season, based upon 1.6-1.7 PAL (seated work with discretion to move around) and addition of 0.3 (significant amounts of sport and strenuous activity). For further context, an average PAL for rugby union players (U16-U24) who were training/competing in-season was 2.0±0.4.
I have created a spreadsheet where you can predict energy intake based upon the three prediction equations above (click here to download).
Okay so now we have predicted how the energy intake required to maintain current body mass. However, as you are reading this article, I assume you are interested in decreasing your fat mass. Below are the suggested rates of loss based upon the guidelines put forward by Alan Aragon previously outlined in article one. There will be inter-individual variation with regards to rate of of fat/body mass loss, especially in certain individuals who may be able to increase muscle under such conditions. Those who may wish to lose at a quicker rate than suggested may find that this comes with a greater risk of muscle mass loss.
A typical strategy to decrease body mass is to utilise a weekly 3500kcal deficit to lose 0.5kg (1lb) of fat/body mass per week. Alternatively, some individuals may opt for a more aggressive strategy via a 1000kcal daily deficit. However, caution must also be used with the utilisation of a higher than required deficits, as there is a risk that such an increase could result in increased lean mass loss in athletic individuals, especially those already lean. Further consideration must be given also to when contact sessions are increasingly implemented over the pre-season period, as collision based training increases energy expenditure, which can therefore influence the energy deficit initially implemented. Based upon Alan Aragon’s suggested rates of loss outlined in the table above, I would encourage you to individualise any nutritional strategy.
It is important that once you have implemented your nutrition strategy you then regularly track your progress – methods of tracking progress were previously covered in article two. The data derived from tracking body mass and body composition can highlight whether kcal intake needs to be increased, decreased or kept the same according to how you have progressed thus far. I would encourage all players to track progress of both gym and conditioning progress (you or your S&C should already be doing this), whilst additionally some individuals may also wish to track daily wellness data to provide further insight. I have created a spreadsheet where you can log daily/weekly progress (click here to download).
Structure of Daily/Weekly Energy Intake
It is important to stress that consistency is needed when implementing such a nutritional strategy for the achievement of daily targets, and ultimately your weekly targets. It is is easy to sell yourself short by not being consistent with energy intake and therefore not progressing at the expected rate. It is therefore important to opt for a dietary setup that you will be able to adhere to, whilst suiting your individual training schedule. I shall now talk through two possible structure options:
This would be considered a linear approach, as kcal intake is the same each day of the week. For example, if your maintenance kcal intake is 3000kcal and you are looking to lose 0.5kg per week then you would need to decrease weekly intake by 3500kcal. This on average over the week would require a 500kcal daily deficit, which would bring your average daily intake to 2500kcal.
This would be considered a non-linear or undulating approach, as kcal intake varies across the days of the week. For example, if your maintenance kcal intake is 3000kcal and you are looking to lose 0.5kg per week then you would need to decrease weekly intake by 3500kcal. As above, this on average over the week would require a 500kcal per day reduction from maintenance daily intake, which would bring your average daily intake to 2500kcal. However, the intensity/volume of your training sessions (e.g. weights, conditioning) or rest day would require varying amounts of daily energy intake. Therefore, you could vary your energy intake over different days to accommodate this, but when averaged out over the week you would still be a 3500kcal deficit.
As you shall read during this section, protein intake is indeed important during a fat loss phase with regards to the maintenance muscle mass, or in some instances the enhancement of muscle mass. However, first a little theory to set the scene with the goal to help you understand the importance of protein and muscle.
If you just want to know how much to eat? Scroll to the next sub-section – ‘Daily Protein Intake’.
I want to first introduce you to two key processes:
Muscle protein synthesis (MPS)
Muscle protein breakdown (MPB)
A common analogy utilised to explain their role is that of a wall. How does this apply? Well, think of your muscle as a wall. The bricks that comprise this wall can be compared to proteins. MPS is the process of building the wall by adding bricks (protein), whereas MPB is the removal of bricks (protein). When at rest, and in a fasted state, the rate of MPB is greater than MPS, which results in a negative net protein balance. However, when protein is consumed there is a transient increase in MPS above rates of MPB, resulting in a positive net protein balance. Following resistance exercise MPS rates are primed for an increased sensitivity to protein feeding. Following resistance training the elevated rates of MPS remain above resting levels for 48hrs within non-resistance trained individuals, whilst persisting for up to 24hrs in resistance trained individuals. It is the repeated accumulation of resistance training, protein feeding and periods of positive protein balance over time that leads to muscle hypertrophy (increase in muscle size).
Okay so we have covered what the importance of MPS and MPB and their role in the development of muscle, but what happens to these processes during energy restriction? When within an energy deficit MPS has been found to be the main adaptive mechanism with a decrease in MPS rates found, with MPB pretty much unchanged. Why is MPS reduced in such conditions? As we discussed in part three of this nutrition series, building muscle is a energy costly process. It has therefore been put proposed that in the face of energy restriction your body induces a “compensatory decrease in energy-consuming processes …with a greater relative proportion of amino acids catabolised for energy production“. A focus of the nutritional and training intervention should therefore be to minimise the decline in MPS. How can this be achieved? Simply by implementing a resistance training programme and an elevating protein intake above maintenance needs.
Daily Protein Intake
During pre-season professional rugby union players been reported to consume on average daily protein intakes of around 2.5g per kg of body mass. Individual intake ranged from 1.6 – 4.0g per kg of body mass in European rugby union players and 1.5 – 2.9g per kg of body mass in Australian rugby players. Note: Caution should be utilised when interpreting the protein intakes of the above European and Australian rugby players as we do not know their individual goals.
To give some context to these numbers, 0.8g per kg of body mass is the recommended daily intake to cover the needs of 97.5% of the population. However, this is the intake to avoid protein insufficiency and therefore cannot be considered applicable to athletes seeking adaptation to training. For individuals engaged in resistance training when in eating at maintenance or in a calorie surplus a protein intake of 1.6 – 2.2g per kg of body mass is recommended. However, as discussed in the previous section, daily protein intake is suggested to be higher when in a calorie deficit at roughly 2.3-3.1g per kg of body mass.
DAILY PROTEIN INTAKE = (BODY MASS in kilograms) x 2.3 to 3.1
A recent research review highlighted the benefits upon body composition via different pathways when consuming higher dietary protein intakes. Where possible an emphasis should be placed upon quality weight loss, with a decrease in fat mass and increase in fat-free mass. Three key influences upon such an approach include:
Satiety – Protein consumption can influence neural and hormonal pathways that influence appetite. For individuals that are therefore reducing energy intake, increasing protein consumption can aid the feeling of fullness.
Thermic Effect of Food – Of all the macronutrients (carbohydrate, fat and protein) protein expends the greatest amount of energy with regards to its digestion and absorption. Therefore, increasing the contribution of protein within dietary intake will increase energy expenditure.
Fat-Free Mass – To stimulate muscle protein synthesis requires the ingestion of protein (amino acids), particularly high quality protein sources (e.g. eggs, dairy, meat, chicken, turkey, fish), which are rich in essential amino acids. The combination of resistance training and protein intake further enhances the MPS response. The maintenance, or in some instances increase, of muscle mass, is not only desired for performance or aesthetic reasons, but also for our health.
Individual Protein Dose
So, how much protein is required in a single meal or snack to optimise the MPS response? Is this a saturable process? Initial research suggested that the consumption of 20g of protein (around 0.25g per kg of body mass) was found to maximally stimulate MPS, with no statistically significant benefit by ingesting a larger 40g protein dose amongst healthy individuals with a range of training experience and trained individuals. With MPS found to be optimised at 20g, protein intakes higher than this were oxidised at a higher rate or utilised for other processes within the body. However around a 10% mean increase in MPS was seen when consuming 40g as opposed to 20g, which suggests there may be some additional benefit for those looking to leave nothing on the table with regards to their gains. Interestingly, recent research has suggested that a 40g protein dose is superior to 20g in optimising MPS post whole body resistance training, with the 40g dose displaying a 20% greater response. It is important to highlight that the greater amount of muscle mass recruited in this study (whole body resistance training) compared to the previous (lower body training only) may have therefore required a greater demand for protein to optimise MPS.
Although initial suggestions stated that a protein dose of 0.25g per kg of body ass would optimise MPS, this has since been increased to 0.4g per kg of body mass to account for inter-individual variation.
Protein content of common foods:
Protein content of common vegetarian protein sources:
Protein is comprised of building blocks, otherwise knowns as amino acids. There are 20 amino acids, with 11 considered non-essential (synthesised within the body) and 9 essential (required via dietary intake).
(1) Essential Amino Acid (EAA) Composition
EAA play an important role in the stimulation of MPS, with 10g of EAA (equating to 20g protein) found to optimally stimulate MPS (Cuthbertson, 2005). The EAA composition of a protein source is therefore predictive of its ability to stimulate MPS. However, “the leucine content of a protein is the strongest determinant of the capacity of a protein to affect MPS and likely hypertrophy”.Why is this so? Well, the EAA Leucine is often refereed to as the metabolic trigger that triggers a rise in MPS. Therefore, it is important that if looking to optimise MPS you consume foods rich in all EAA, with Leucine being of particular importance.
(2) Digestive/Absorption Properties
Quite simply, this refers to how quickly a protein source can be broken down, enter the blood and be utilised by muscle for MPS. Rapid digestion to enable an increase amino acids and in particular leucine to trigger MPS.
Table data as reported by Van Vliet et al., (2015)
When compared to animal-based protein, plant-based sources are typically of a lower EAA content – see the table above. Additionally, plant-based protein have a lower digestibility than animal protein sources. Therefore, via the previously discussed criteria of assessing protein quality, plant-based protein sources can be considered of lower quality. However, this is not to say they cannot be of use – they certainly can and they can make up some quite tasty meals! However, you have to be a bit more mindful of putting your meal together, as a common solution is to combine sources to build a complete EAA profile.
If incorporating plant-based protein sources within your dietary intake, it is important to mindful that you will require a greater overall protein serving to match the EAA content of that seen in an animal protein source. Note that the the lower content of protein/EAA seen within the majority of plant-based protein sources typically also come with a higher kcal content, typically via increased carbohydrate.
A common misconception when it comes to protein intake is the belief that more is better. You may have seen at some point the individual with the Tupperware cramming in some protein on the hour. Such people are of the belief that continually consuming protein via high meal frequencies will continually stimulate MPS and lead to continued muscle mass gains – if only!!
The ‘muscle full effect’ suggests that in the face of continued protein feeding the muscle will eventually become refractory once maximally stimulated, with excess protein either oxidised for energy or utilised for other roles within the body. Following the consumption of a saturable dose of protein, a 30 minute lag follows before a large increase in MPS, which peaks around 90 minutes before returning to baseline at roughly by 120mins, highlighting the transient nature of MPS . This is where the basis for protein feeding every 3-4 hours has been suggested to maximally stimulate rates of MPS.
As analogy let’s take a light bulb …
Interestingly, recent research within Australian rugby players found that “there was no clear effect of increasing protein distribution from approximately 4 to 6 eating occasions on changes in lean mass during a rugby preseason”. If creating a hierarchy of importance when dieting, ensuring daily protein targets are met would be of greater priority than distribution and timing. However, an individual looking to leave no stone unturned in their pursuit of optimising their muscle mass may opt for distributing 4 protein containing meals/snack, with consumption every 3-5 hours and an additional pre-bed casein feeding.
‘The anabolic window’ is a time period of great notoriety, particularly amongst resistance training individuals, where the timing of protein pre and post-training is considered immediately necessary for super-compensated muscular repair and remodelling.The increased sensitivity of MPS to protein feeding following resistance training highlights that protein consumption following resistance training is of importance for those individuals with goals regarding increased muscle mass. However, such a short window of anabolic opportunity is not as narrow as the often mentioned 30-60 minute window.
Based upon the research it has been put forward that the timing and contents of the pre-workout meal dictate the timing needs of the next protein feeding due to the time course of digestion and absorption. The closer the meal is consumed to the training bout, the longer the time needed for post-training protein consumption due to the sustained delivery of amino acids. Based upon previous findings of muscle protein stimulation every 3-4 hours, and the typical resistance training bout of most individuals lasting 60 minutes, individuals wishing to optimise their muscle gain efforts may look to consume protein 90mins pre-training and ensure protein within 90 minutes following training. This can be adjusted based upon personal preference with regards to how close or far away you wish to consume a protein dose pre-training. Individuals opting for a large mixed meal (containing both protein and carbohydrate) should be aware that this may be digested and absorbed over a longer period of time (roughly up to around 5-6 hours). This may further decrease the necessity for immediate post-training protein consumption if consuming a meal a couple of hours pre-training. For example, again based upon a 60 minute training session, if consuming a decent sized mixed meal 2 hours pre-training, one would look to consume protein within the 2-3 hours following training. In the scenario that an individual opts to train fasted first thing in the morning prior to work there should be an increased emphasis upon the timing of protein soon after the completion of training, likewise those individuals who have not consumed a large mixed meal within the previous 5-6 hours.
It is important to remember …
The consumption of protein prior to sleep is a strategy of great interest amongst the strength training population. This strategy was put forward based upon the principle that the overnight period presents an extended fasting period where an individual would be expected to be in a negative protein balance (MPB > MPS). Therefore, to promote a positive protein balance whilst sleeping it has been suggested to ingest a casein based protein feeding (slow release protein) at a higher dose (around 30-40g) than that recommended for a daytime dose, which equates to roughly 0.5-0.6g per kg body mass. A popular approach is to integrate dairy based foods (e.g. greek yogurt) into this feeding opportunity (food-first approach where possible), or for those that wish not to opt for food a casein based protein supplement could be utilised.
When setting up a diet for body composition once protein intake has been set, I then like to calculate fat intake and then fill the remaining kcal intake with carbohydrate. Why is fat intake important? Fats are an energy source for low intensity activity, an important part of cell membranes, aid the absorption of fat soluble vitamins and aid immune function. It is important that essential fats, omega-3 and omega-6, are included within the diet. The American College of Sports Medicine in their recent position stand recommend that fat intake should be between 20-35% of total energy intake. From experience working with a variety of athletes I would typically see fat intake at around 0.9 – 1.4g/kg/body mass depending upon the individuals preference and training schedule/demands.
As mentioned above, during pre-season I set both protein and fat intakes first, and then fill the remaining kcal intake with carbohydrate. However, during the season I typically set carbohydrate second following protein to ensure that sufficient fuelling for training/competition/recovery is met (occasionally I may do this for pre-season depending upon the individual/goal).
Carbohydrate intake is an important fuel for high intensity activity. With both field and gym sessions being of decent intensity and volume it is important to ensure you are fuelling appropriately, especially if within a planned energy deficit. Chronically under-fuelling during pre-season may not only decrease training performance/progression and cause unfavourable lean mass losses, but may also suppress immune function, impair adaptation and increase susceptibility to injuries. The American College of Sports Medicine in their recent position stand suggest the following carbohydrate intakes, although these guidelines were not specifically based from the rugby athlete:
The majority of the time dietary setup for fat loss comes down to personal preference – what approach can you adhere to? However, it is important to consider that rugby players who are engaging in high intensity pre-season training should ensure appropriate fuelling for training sessions.
I didn’t want to end this article without a mention of the importance of micronutrients, which is often overlooked. To support not only your training, but also your health, it is important to include a variety of nutrients within your dietary intake.
There you have it. An overview of how to construct dietary intake for fat loss with reference to energy intake and macronutrient consumption. So far in this nutrition series we have covered: goal expectations and rates of progress, monitoring body composition, muscle gain and fat loss. Part five of this nutrition series shall address supplement considerations for the rugby union athlete.