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Sports nutrition for cyclists

Getting The Basics Right

One of the most frequent questions  I get asked pertains to food and hydration for training and racing.   Without a doubt poor nutrition is responsible for many a cyclists good intentions going pear shaped.  Getting it right can be quite simple but first you need to know the basics, so here they are.

Carbohydrate Intake

Of all the energy components carbohydrate intake is the most important for cyclists.  However throughout the year the volume of carbohydrates you need to consume will change depending on the type of training you are undertaking.  When doing base training the intensity is lower and you are generally burning a higher percentage of fats.  This means there is less need to ‘fuel up’ or replace carbohydrate stores.  This doesn't mean you don’t need any carbohydrates, it just means you need to eat slightly less than you do when you are doing the higher intensity training closer to your races.

So how much do you need to eat.  Well there are two general guides to carbohydrate consumption for endurance athletes.  The first is that is should account for ~60% of your daily energy intake and the second is that you should consume 7-10 grams per kilogram of body weight. So for someone weighing 65kg this would be 455g - 650g per day (that's 7280kj - 10400kj).

The AIS has a good fact sheet on Carbohydrate intake and it can be found at http://www.ausport.gov.au/ais/nutrition/factsheets/basics/carbohydrate__how_much

Protein Intake

As with carbohydrates, protein intake can vary during the year depending on what type of training is being done.  Again there are two broad guidelines that endurance athletes can follow: 20-30% of daily energy intake or 1.2-1.6g per kilogram of body weight (up to 1.7g during strength training).  So for our 65kg athlete this would be 78g - 104g per day (that's 1326kj - 1768kj).

Additionally it is preferred that the protein consumed is that a mixture of protein sources are used.  The reason for this is that some foods (e.g. breads) provide protein with incomplete amino acids (i.e. some are missing) and these missing amino acids need to be obtained from other food sources.  Protein intake should also be staggered throughout the day (every 2-3 hours) for maximal benefit.

Again the AIS has a good fact sheet on protein intake and it can be found at http://www.ausport.gov.au/ais/nutrition/factsheets/basics/protein_-_how_much

Fat Intake

It may seem odd but consuming fat is actually an essential part of the human diet.  Where people go wrong is the type and quantity of fat consumed.  Fat is required to assist in cell regeneration and other bodily functions, as well as being an important fuel source for daily activities and low intensity exercise.

In general your daily diet should be limited to no more than 1g per kilogram of body weight per day.  So for our 65kg athlete that's 65g per day (that's 2405kj)

The type of fat consumed is also important and you should avoid saturated and 'trans' fats.

Alcohol Intake

Alcohol intake is generally not recommended during periods of intense training or competition and there are a range of negative effects from excess consumption.  However, it has long been recognised that having a drink can be an important social part of Australian sport, therefore its important to consider a few guidelines to help you decide when and how much to drink.  Basically alcohol leads to dehydration so its important not to drink when you are already dehydrated or just before a training session or race that will stress your hydration levels.  Alcohol also impairs judgement and decision making so avoid it when you will need to concentrate.  It is also important to remember that alcohol takes some time to leave the body and just as drivers can get caught drink driving the morning after a drinking session, riders can also retain a high blood alcohol level the morning after, so avoid drinking to excess when you have to be up early to train the next morning.

Along with being intoxicating Alcohol also contains 29kj per gram and is only second to fat in energy density.   Furthermore when the body detects alcohol in its system it becomes a priority fuel and will attempt to burn it off before utilising carbohydrates or fats.  This is important as if alcohol intake is combined with food intake it is possible that the energy consumed from the food sources will be transferred to fat and stored for later use, in other words you gain weight.

AIS factsheet on alcohol is at http://www.ausport.gov.au/ais/nutrition/factsheets/basics/alcohol_and_australian_sport


Pre-training or race nutrition

Ok, so you know that you need to eat ‘x’ amount of carbs, protein and fats, but how can you use that information to increase your performance.  Well one way is to ensure your body has sufficient energy stores before a training session or race.   Depending on the session that is planned the solution may range from several days of carbo-loading to a simple pre-event meal. 

Carbo-loading is the practise whereby an individual ensures all of their glycogen stores are at maximum capacity before an event.  There are several strategies to achieve this but most include consuming a higher than normal amount of carbohydrates in the days leading up to the event.  (See http://www.ausport.gov.au/ais/nutrition/factsheets/competition_and_training/carbohydrate_loading).  

A pre-event meal on the other hand is a shorter term strategy that targets carbohydrate intake in the hours before an event.  These carbohydrates will be digested and enter the blood stream just before and during the early stages of the event, thus boosting available energy.  The timing of the pre-event meal will depend on the type and quantity of carbohydrate being absorbed but a general guide is approx 1.5-2hrs before the start of the event.

Once the event or training session is underway it may also be necessary to supplement the bodies energy stores by consuming more carbohydrates as the event progresses.   Whether this is required or not depends greatly on the duration and intensity of the event.  When the body has been well fuelled prior to the event there is usually sufficient glycogen stores for 1-2hrs of intense competition.  Beyond this it is recommend that athletes consume up to 1g of carbohydrates per kilogram of bodyweight every hour.  So for our 65kg athlete this is 65g of carbs per hour.  This can be obtained from a variety of sources and its beneficial to ensure the carbohydrates consumed are of different types, i.e. a combination of glucose, fructose,etc.  In these cases you can consume more than 1g/kg body weight and therefore enhance your endurance performance.  A typical 500ml bidon of Gatorade or Powerade provides ~30g so one bidon per hour takes care of almost half of the energy requirement for the 65k rider.   Add in some solids or semi-solids such as gels and that should be enough.   Along with the quantity it is also important to consider the rate of digestion and absorption of the carbohydrates.  High GI carbs are best, while low GI foods can often lead to feeling full and not wanting to eat.  This can lead to problems late on in longer events.

Hydration is also important and in general you should aim to consume between 500-1000ml per hour (depending on temperature and exercise intensity).   There are very few exceptions to this guideline, one of which is for short duration events.  In these cases a properly hydrated athlete should rarely suffer from dehydration and hydrating during the event may not be required.  For example a time trial of less than an hour.  However where temperature is an issue hydration is always preferred.

More information can be found at the AIS website at

http://www.ausport.gov.au/ais/nutrition/factsheets/competition_and_training

Recovery nutrition

While eating to fuel training sessions and events is of vital importance, refuelling and recovery nutrition is seldom considered by most athletes.  However, its is vital to ensure that maximum benefits are gained from the training session and that the next session can be completed with as little fatigue as possible.

The general recommendation is that after exercise you should consume a mixture of carbohydrates and protein.  Approx 1g of carbs per kilogram of bodyweight and 20g of protein within 30-60 minutes of completion of the training or event.  It is also preferred that the carbs are high GI as they will be absorbed quicker.  For endurance athletes the protein works to help rebuild the aerobic system and adapt to the training, while in strength training athletes it goes to developing muscular systems.  If the exercise was sufficiently taxing then a second post-event meal will also be required.  This should be within 1-2hrs of the completion of the event and preferably contain low GI carbs.

It is also important not to forget re-hydration.  If the session was a training session you can often determine sweat losses by using a scale (weight yourself before and after the session).  The majority of weight lost during a session is sweat and dehydration.  If you have lost weight then you should aim to consume ~1.5 litres per kilogram of body weight lost.  For example if out 65kg athlete lost 1.5kg over the course of a long ride they should aim to consume approx 3 litres of fluid in the hours following the session.  Nb:  This shouldn't all be done at once as there are certain health risks from excess fluid consumption.   The extra quantity of fluids is required as not all fluids are retained, some is passed as urine following the event.  Furthermore the athlete should revisit their fluid intake while training and aim to increase the volume consumed to avoid dehydration in the future.

Planning

One of the key aspects to good sports nutrition is planning.   Now that you have all the basic information you should be able to start setting out some plans for timing of meals, types of foods, etc. to help improve your sports nutrition.

Losing weight

No discussion regarding sports nutrition, especially for cycling, would be complete without discussing weight loss.     Fundamentally weight (preferably in the form of fat) is lost when the energy expended is greater than the energy consumed.   To expand this further it is also worth considering that fat stores are decreased when fat burnt is greater than fat intake and the additional fat stores created from excess carbohydrate consumption.  Sounds a bit technical but, each energy type needs to stay in balance.  If more carbohydrates are consumed than burnt then the excess will be converted to fat.  So while it is important to keep fat intake in check it is also important to do the same with carbohydrates.

The good news is that a consistent approach of consuming less energy than expended will usually lead to weight loss without the person having to pay too much attention to the finer details.   However this poses a fundamental question, how much energy do I need to consume?

Well for athletes it has been found that you can predict your base energy requirement quite well using the Harris Benedict equation, which is

Males = 66.47 + (13.75 x body weight) + (5 x height) - (6.76 x age)

Females = 655.1 + (9.56 x body weight) + (1.85 x height) - (4.68 x age)

where body weight is in kg, age is in years and height is in cm

The result of this equation will give you your base daily energy requirement in calories (multiply by 4.184 for kj).  This is the amount of energy you would go through if you slept all day.  To get your daily energy requirement its usually best to then divide this figure by 24 to get an hourly rate and then do the following type of calculation (example below)

8 hrs sleep x base energy expenditure + 16 hrs Very Light Activity(*see below) x base energy expenditure x 1.5

So if your base energy expenditure was 300kj per hour then this would be:

(8 x 300) + (16 x 300 x 1.5) =  2400 + 7200 = 9600kj per day

This is actually the easy bit.  Where it gets difficult is when you add in exercise and various levels of daily activity.  Fortunately most modern day heart rate monitors or training devices predict energy expenditure with a reasonable level of accuracy.   You can then subtract x hrs of daily activity and replace it with the exercise energy.  Where the daily activity varies you can use the following multipliers

  • Rest (sleeping or lying down) = 1.0
  • Very Light (Seated or standing activities, basic housework, etc) = 1.5
  • Light (walking, some trades, house cleaning) = 2.5
  • Moderate (fast walking, gardening, etc) = 5
  • Heavy (Heavy manual labour) = 10

Nb: You can also find a variety of free apps on the internet that do these calculations.

Finally, energy intake.  If you need to lose weight then its just as important to track energy intake.  Calorie King Australia (http://www.calorieking.com.au/) is a fantastic website which contains nutritional information on a huge number of products and should take care of all products where you cant get the information off the packet.

Jason Mahoney Wednesday 07 August 2013 at 08:23 am | | Default, News, Race Reports, Rider Info, Tips, Training Sessions, Linkdump

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