Nutritional Information for Triathletes

Nutritional guidelines from Triathlon Ireland

Water consumption needs to be adequate:  run out of water and you’ll be dead within 2 days. Become dehydrated and your performance will bomb.

You need carbohydrates to fuel intensive exercise:  but probably not as many as you’ve been told to eat before. Excess carbs at the expense of protein and good fats – will turn you into a sugar burning machine. I want fat burning machines, who use sugars to turbo charge their workouts. This is a key concept – become carbohydrate aware, know your carbs and know when to eat them for maximum performance and minimum body fat.

Eat protein – with every meal:  endurance junkies almost always neglect protein intake. The result, muscle protein breakdown, poor recovery, low energy, immune function and lack of strength. Eat more protein to reverse these trends.

The same’s true for fat:  with an over emphasis on carbohydrate foods good fats are often neglected. Our cells are 60% fat. You need to eat more good fats, know where to find them – and incorporate these into your meals. Eating a higher protein, fat and fibre diet will make losing body fat more likely – and up regulate fat burning enzymes. Good fats also nourish our immune, nervous and inflammation regulation systems – so they help with all aspects of recovery and repair. Read on for a special fat which burns like a carb! And can upregulate metabolism.


1.  Hydration

Drink plenty of water throughout the day and during training sessions. Being well hydrated improves how you feel and perform.  The average adult requires at least 2-3 litres of water a day.  This requirement increases if you exercise.  Thirst is a poor measure of dehydration. You become dehydrated long before you feel thirsty so drink water continuously throughout the day.  Alternatively, choose fruit teas and herbal blends, and water flavoured with a little fresh fruit juice. Isotonic drinks should be consumed before – during and after training where appropriate.

2. Preparation

This point mainly concerns preparation for competition. It’s vital that your muscles are loaded with carbohydrate (CHO) if you want to perform to your maximum level, as CHO is the primary fuel for high intensity exercise. If you are training for fat loss then this is less important, as a lack of CHO will actually promote the utilisation of fat.

Preparation also refers to your cooking; you should prepare your food yourself and be organised about planning your meals and menus. This way you know exactly what’s going into your body and you can stick to eating at set times, getting into a routine to support good health!

3. Regeneration

Post exercise recovery is paramount. You must be meticulous with your post workout intake – the quicker you recover the better you will perform week in week out.CHO rich foods with a High glycemic Index (GI) will aid recovery after exercise. If you are lean and bodyfat isn’t such a concern, you can be more generous with carbohydrate intake. This is also a vital time to top up your body with the protein you’ll need for repair and to support the immune system’s response to exercise. Make sure you sleep adequately. You should wake up feeling refreshed and will be able to achieve more physical gains, performing better week in week out.

4. Quality

Deficiency & Toxicity will severely interfere with your ability to perform week-in week-out at the highest level.  Organic, high grade produce is the best way to avoid these problems, with supplementation always an option if you don’t think you can obtain all you need from a balanced diet.

5. Quantity

The most important thing is to stick to eating at set times and set portions. Be strict with yourself. You may have been given suggested serving sizes. For dried staples, such as rice and porridge they’re easy to stick to if you use scales to make yourself familiar with a certain portion-weight, then use a specific scoop/spoon for subsequent portioning. For instance, a 40g portion of porridge oats (150Kcal) can be easily measured by filling a ½ pint beer-glass to the “bulge” about 2/3 of the way up. Increase or decrease the portion sizes depending on your goals.

6. Frequency

Eat around every 3 hours. Look at food as feeding opportunities, every time you consume food you can either gain or damage your health.  Each meal should contain high quality protein, CHO and vegetables.

7. Next Step

Once you’ve mastered the basics – you need to look at fine tuning. You need to know about acid base reactions in foods once you eat them – excess grain consumption for instance is acid forming in the body! – More acid means more minerals and base aminos like glutamine being used to balance acidity. Not good for athletes to lose magnesium, calcium and glutamine if they are in intensive training.

Also what you eat when you are competing is key to success – in part II on eating for endurance sports we’ll be looking at acid base reactions (PRAL) – plus supplementation in and around your event. We’ll be breaking down sprint, Olympic and iron man distances and giving you secrets the elite pro use to maximise their performance…..


Hydration must be your foremost priority. Each meal should consist of a portion of protein, complex carbohydrate (CHO) and vegetables. An effective strategy for fat loss has been revealed to be one of reducing fat in the diet by substituting it with protein. CHO should still be the major source of energy and, and consuming this with green vegetables, high in cellulose, has been shown to allow this energy to be released slowly, maintaining constant blood-sugar. This will mean your energy levels don’t fluctuate too much.


  • The average adult requires at least 2-3 litres of water a day (2).  This requirement increases if you exercise.
  • Studies report performance losses after just 2% dehydration (about 1.5L of sweat).
  • Salts increase water retention as well as thirst, encouraging rehydration. Added CHO has also shown an ability to improve fluid balance, as well as protein.
  • Not only will dehydration affect your muscles’ ability to function, but the loss of salts may eventually affect your nerve function, reactions and concentration.
  • Thirst is a poor measure of dehydration. You become dehydrated long before you feel thirsty so drink water continuously throughout the day.
  • The best measure of fluid balance is urine colour, this should be clear and pale at all times.  Dark yellow urine is an indicator of dehydration, though some multivitamins may give the urine a bright yellow appearance.
  • Rehydration drinks contain salts, and it’s also advisable to drink water when you eat food. If making your own, use full-sugar squash for recovery, or diluted fruit juice or low sugar-squash at other times, adding a pinch of salt.
  • Start the day with a mug of freshly boiled water and a slice of lemon.  In summer add a fresh sprig of mint and fresh lemon slices to a jug of cold water.
  • Drink from a bottle of water to measure daily intake until you are used to drinking enough.
  • Weigh yourself before and after exercise.  For every kilogram lost, a litre of water is lost.


Carbohydrate (CHO)  

  • Carbohydrate (CHO) is the body’s primary energy source, essential for short bursts of intense activity. It is stored in the form of glycogen in the muscles and the liver.
  • You need to ensure an adequate supply for intense exercise and replenish afterwards.


  • Replace some starchy carbs with fibrous carbs at each meal.  This will increase fibre and help fill you
  • Avoid large carbohydrate meals, as these will make you sleepy and excess calories will be converted into body fat.
  • Always choose whole grain options.  Brown rice, whole-wheat cereal and whole grain breads are always higher in nutrients and have a lower glycemic index.
  • Starchy carbohydrates should be limited in the evening meal where fat loss is a goal, as the need for an energy source at night is limited.

After training

  • Insulin released in response to CHO prevents muscle-breakdown & promotes synthesis.
  • In the “recovery period” immediately after training, we can take advantage of these properties.
  • More “sugary” high GI carbs (white rice, “hypertonic” sports drinks etc) should be eaten to help “spike” insulin levels and to promote the uptake of sugars, protein and nutrients for repairing muscle.
  • Replace brown with white rice. Try and eat a good portion of carb and protein within 45 min of training.


  • Insulin acts as a signal to your body that you are fed, and so can promote the storage of fats and conversion of carbs to fat. Generally we don’t want too much simple/sugary carb for this reason.
  • Eating complex carbs like brown rice and wheat free pasta when recovery isn’t the primary objective, will encourage your body to use this carb gradually for energy, instead of just storing it as fat
  • Eating complex carbs will also let your body burn fat more efficiently and prevent you feeling tired once all the CHO has been stored
  • Insulin also interacts with other hormones released from training.
  • Growth Hormone, released after exercise, promotes muscle-building, and in a lower-CHO/insulin environment also causes your body to burn fat. If there is a lot of CHO and insulin, Growth hormone then has the opposite effect on fat metabolism, causing fat to be stored.

Suggestions for a small portion, providing around 150Kcal (adjust depending on your goals)

  • Brown rice (40g serving)
  • Brown pasta (40g serving)
  • 1xSmall sweet-potato (80-100g cooked)
  • 1xSmall potato (80-100g cooked)
  • Wholemeal bread- 2 medium slices


  • Protein is the main structural component of muscle tissue as well as providing a source of energy as an alternative to CHO during exercise and being the primary fuel for cells of the immune system.
  • At least 20 – 25% of your daily energy intake should come from protein.
  • Protein should be included at every meal, this will help control blood glucose levels support muscle and improve appetite control.
  • Protein is required in higher amounts during weight loss in athlete. Replacing calories from fat and CHO with protein is an effective strategy for fat-loss.
  • Using protein as a source of energy requires it’s degradation, followed by inter-conversion of amino acids to glycogenic and ketogenic substrates, requiring the use of around 30% of the protein’s calories.
  • Protein intakes of around 1g per lb (2.2g per Kg) are effectively used by athletes wishing to maintain muscle mass, considering their body composition.
  • Choose lean meat and poultry, avoiding prepared meals and processed meats (Preparation!).  Fish is a superb source of protein, it is low in fat and oily fish like mackerel have the added advantage of being high in omega-3 fatty acids.
  • Grill, bake, steam or poach fish in preference to frying.  Try to avoid farmed fish and choose wild and organic fish whenever possible.  Avoid pork, as it is the most fatty of red meats.
  • Peas and beans (legumes) are excellent sources of protein and fibre, especially when combined with wholegrains.  Most plant proteins do not contain all the essential amino acids (animal protein does); combining different sources of plant protein solves this problem.
  • Legumes should be eaten with wholegrains, e.g. brown rice and lentils, houmous with wholewheat pitta bread.  Plant proteins are very low in fat and have a very low glycemic index (see later), this means that they cause a slow release of glucose into the blood.  Baked beans have a low glycemic index, are cheap, convenient and easy to store.  Serve as a filling for baked potatoes or on toast.
  • Nuts are also a useful protein source but they should be eaten in moderation as they have a high essential fat content.
  • Choose a mixture of almonds, pecans (The King of Omega-3!), walnuts, and Brazil nuts, hazelnuts, cashews, pumpkin, sunflower and sesame seeds.  Add them to a salad or stirfry, or eat them as a snack.  Avoid nuts that have been roasted in oil or are salted.
  • Tofu is a bland, tasteless food that can be prepared, flavoured and cooked in a multitude of ways so that it can take on the flavour and texture of any ingredients it is combined with.

Suggestions for a portion, providing around 30g of protein:

  • 1 Skinless chicken/turkey breast
  • Mackerel
  • 4 large eggs (have one full egg plus 3 whites in each portion)
  • 1 can tuna

Fruit and Vegetables

  • Aim for four to five servings of vegetables each day and one to two portions of fruit.

Explanation and advice

  • The fibre in vegetables, when eaten with carbs, slows down the release of CHO into the body, reducing swings in blood sugar control. Fibre has been identified as having many beneficial effects including control of blood glucose, decreasing blood cholesterol, improving bowel health and even controlling appetite

Examples of high fibre foods:

  • Oats
  • vegetables
  • wholewheat flour,
  • bran,
  • fruits with edible seeds
  • Getting your “5 a day” will give you a selection of vitamins and minerals to help all of the reactions in your body proceed.
  • Enzymes are machines in your body that are held in the correct shape by minerals like iron and magnesium. Vitamins are often involved in these reactions…they give them a kick-start (acting as “cofactors”).
  • Dark-green veg are often high in fat-soluble vitamins like vitamin E and contain some good fatty acids like omega-3. Eating these will put the correct fats into the “membrane” (like a skin) that surrounds every one of your cells, as well as protecting these fats from damage.
  • Balance your vegetable intake between the orange/red and green varieties.  A good rule to follow is simply to try and get a good amount of “colour on your plate” for example, mixing up light green lettuce with the deep dark green of spinach or the bright orange of carrots.  They can be eaten raw and cooking most vegetables takes only a few minutes if you steam, stir-fry or microwave them.
  • Choose fresh and organic vegetables wherever possible (Quality!).


Examples of green veg side dishes

  • Stir-fry Kale in spray olive oil with garlic and ginger. Add Chinese 5-spice
  • Fry Cabbage in spray-olive oil with onion, adding finely chopped apple after 3 mins, covering with stock and simmering till tender
  • Add Spinach leaves/shredded raw cabbage to salad leaves
  • Chop celery finely into “matchsticks” and add to finely chopped apple, carrot and lime-juice with 1 tsp honey
  • Spinach can be easily cooked in 2-4 mins and drizzled in soy-sauce