Sports Coach Logo Sports Coach Training Principles Fitness Components



text Translator



site search facility





Eating for Performance

Lance Smith explains the role of your diet in running performance.

An analogy can be made on the role of diet in running performance – this uses the 5000 Parkrun as an example, but the principle applies to all events. In a 5000m genetics (natural attributes, talent) will get you 1 km. Training will take you the next three and healthy eating the final km. But, and it is a big but, without a healthy diet, you will not be able to train well, so what you eat has a big influence on how far you get. The same goes for every athletic event. Talent will take a discus so far, technique a bit further, hard work and training give it more distance, and the right fuel in that machine called your body, the final bit.

It starts with a balanced diet 

What you do for training and after training is essential, but your overall diet is the most critical. It is senseless having high-energy foods or drinks before training and competition and replacement drinks afterward if the rest of your diet is rubbish.

An athlete cannot perform if the body is short of fuel. Make sure you eat a balance of foods, as no one type of food contains all the nutrients necessary for health or top performance.

It is recommended that an active person's diet should consist of around 60% carbohydrate (bread, cereals, vegetables, fruit, pasta), 25% protein (meat, eggs, fish) 15% fat. What are these?

Carbohydrates – the fuel

Quality carbohydrates include grainy bread and breakfast cereals, pasta, rice, noodles, couscous, potato and kumara, legumes, yoghurts, smoothies, custards, and fruit. One or two of these carbohydrate foods need to be present in each meal and snack.

Protein - muscle builder

Protein is essential for muscle growth and repair. Great protein sources include lean red meat, chicken, fish, eggs, low-fat dairy foods, and legumes. At least one of these protein foods needs to be available in each meal and snack.

Fats – go easy with these

Reduce treats such as chocolate, rich desserts, cakes, and biscuits. Nuts, seeds, peanut butter, fish, grains, and olive oil are all healthy sources of 'good' oil for the body.

Dietician Jeni Pearce advises 

Carbohydrate intake should be 7 – 10g for each kg of bodyweight.   So a 55kg athlete needs between 385 to 550g carbohydrates a day. 

Fat intake should be around 1g per kg bodyweight while – so around 55g

Protein 1.5 to 2g per kg bodyweight.  – around 110gm

Some general rules

  • A balanced diet 
  • Regular meals – include 3 veg and 2 fruits (5+)
  • Have breakfast every day - athletes who eat breakfast have better energy levels, grow more muscle, and recover faster from training.  
  • Balance food and drink around training.
  • If working with a nutritionist, have a nutrition plan coordinating with your training/competition periodisation plan.

The Performance Zone

Balancing food and drink around training is important - you are putting extra stress on your body with the hard training you do and need extra nutrition to compensate.

Eat 1 to 3 hours before exercise.  If a relatively large meal – lunch or breakfast – 3 hours; if a small meal – snack- an hour.  This is known as the 'performance zone – the period prior, during, and after a performance that what you eat has the most impact.

Make 'performance zone' nutrition high in carbohydrate, low in protein, and minimal fat – so not chocolate.  Snacks can include muesli bars, fruit, yoghurt, creamed rice, chocolate milk, smoothies, tin baby food, e.g. apple, filled roll, Primo plus a banana, chocolate milk.  Always try to add a piece of fruit to your snack – this increases vitamin and mineral intake, and vitamin C in fruit helps iron absorption.


Stay hydrated.  You are 70% water, so any water loss is going to have a significant effect.  When dehydrated, performance decreases by up to 20%.  You also suffer reduced ability to focus, reflexes not as good (coordination), and tiredness.   Hydration is most important in the 'performance zone'.

You can lose up to 1-2kg bodyweight from sweat loss.   To fully rehydrate, it is recommended to consume 150% of the fluid deficit and electrolytes should be added to replace the loss during sweating and help with water retention.

You can use a sports drink or add a sports powder to your water – these can be expensive, but Raro powder with some salt added gives all you need at a fraction of the cost.

Need – drink around 750ml per hour of intense exercise. Take a bottle with you everywhere.

Competition Nutrition

Do have breakfast – if you have to get up earlier to allow time before competing, do so.  Eat a high carbohydrate meal two, preferably three hours before competing.

Recovery Nutrition

Glycogen (energy stored in muscles) is usually restored at around 5% an hour, but at 7% an hour in the first hours after exercise.  So something high in carbohydrates as soon as possible after training or the run improves recovery rate.  So take recovery foods such as a honey sandwich, muesli bar, ripe banana) in your bag to have straight after or even take food with you to eat between sessions.  These foods are digested quickly and readily replace lost carbohydrates.

It has been advocated that a snack within 30 minutes of exercise is best, but new research suggests there is a 2-hour window, so no need to panic.   

Be Prepared

An interesting study at Loughborough University (England) some years ago had 3 groups of 10 athletes run to exhaustion on a treadmill.  Over the next 3 days, the calorie intake was increased 70% for all runners.  Group one's increase was in fats and protein, group 2 by simple carbohydrates (sweets and confectionary), and group 3 with complex carbohydrates (pasta, fruit).  After three days, the subjects repeated the test.

Group one (fats/protein) increased distance covered by 3%,  group two (sweets) by 23%  group 3 (pasta) by 26%.

So, proof that complex carbohydrates including cereals, bread, fruit, and vegetables) are the best source of energy.


Iron is necessary to carry oxygen to the muscles.   Briefly, if your iron (haemoglobin) is down your muscles receive less oxygen, meaning they cannot produce as much aerobic energy. So your VO2max and anaerobic threshold are reduced.  The result is you cannot maintain as fast a pace.  It is like being unfit.

Athletes, especially women and young males, can be at high risk of low iron status. Signs of low iron can include feeling more tired or weaker than usual, shortness of breath (due to decreased uptake of oxygen), dizzy/faintness. 

The indicator of iron stores is serum ferritin levels. A blood test can determine this. Normal ferritin levels are 10 to 300 ng/ml, but normal is usually not enough for an athlete.

Some athletes experience a fall-off in performance when their ferritin level drops below 50.  Others are OK until it gets to 25.  But the key is if below 25 you are in trouble or are heading towards it.    And it can take as long as three months for you to come right.

If you are a teenager with growth spurts, training hard, or are female, you have a good chance of becoming iron deficient.  If all three apply to you, there is more than a good chance of iron deficiency.

Iron-rich foods such as red meat, kidneys, chicken, beans and nuts, green leafy vegetables, and fortified cereals help boost iron levels. Drinking vitamin C-rich drinks can help iron absorbency or taking vitamin C tablets.

But drinking calcium-rich drinks, i.e. milk will decrease the uptake of iron.

If ferritin levels are down, you may need iron tablets – prescription ones are stronger, or even an iron injection.

I suggest you have a blood test every 3 to 6 months and have one immediately should your training and performance levels decline without apparent reason.

Importantly, seek medical advice, but make sure the doctor understands you are a runner.  Some doctors may see a ferritin level of 12 as being within the normal limits, but it is far from satisfactory for an endurance athlete or anyone in serious training.


  • Nutrition resource, Athletics New Zealand Middle Distance Training Camp
  • High Performance Nutrition – Caryn Zinn Powerpoint presentation
  • Nutrition for Athletes – IAAF - Staying Healthy – article Lance Smith

Page Reference

If you quote information from this page in your work, then the reference for this page is:

  • SMITH, L. (2019) Eating for Performance [WWW] Available from: [Accessed

About the Author

Lance Smith is a practising coach with Athletics Southland in New Zealand with coaching qualifications in sprints, track endurance, road and cross country, steeplechase, and high jump and has coached athletes to national championship medals in all the above events. He is also an active "master" athlete and takes part in track events and jumps.