Eating for Maximum Energy

There are lots of factors contributing to low energy – poor sleep patterns, over-training, daily stress levels, inadequate recovery – the list goes on. What you eat – and when – can also have a big influence on your energy levels. For best results, it’s important to speak with your GP, sports dietitian or health care practitioner for an assessment of all of these factors, but to get you on your way to maximum energy I’ve explained some of the common nutritional causes for athletes not reaching their optimal energy levels.


Inadequate calorie intake is a common cause of fatigue in endurance athletes. Many simply fail to meet the high demands of their training, in which case you may feel low in energy as your body attempts to conserve calories so that it can maintain basic functions. Eating 5-6 times per day (about every 3 hours) will provide sufficient opportunities to consume the calories you need and aid in improved recovery.

In some cases, athletes restrict calories to reduce body fat, but it is rare, in my experience, for athletes with high training volumes to consume enough food to contribute to weight gain. The important thing is to match daily food intake to your training schedule.

Longer or higher intensity sessions require greater fuelling. Triathletes are often time-poor on days with long or double training sessions and often end up eating less than required. In some cases, over-restriction results in a slowed metabolic rate, making a change in body composition (such as getting leaner) very difficult. Sports dietitians use equations to determine the estimated food intake necessary to assist in managing your weight goals.


Exercise, PARTICULARLY RUNNING, promotes the movement of food through the gut. When your body has food to digest, the running motion can upset the digestive tract by making it harder to control the course your food wants to take. On top of this, there is the problem that while you’re running, blood is diverted from your digestive tract, making it function less efficiently. Consequently, problems such as bloating, loose bowels and gas can be worsened during exercise. Certain gut conditions can also cause impaired thinking and low energy levels, as well as a reluctance to eat pre- and during exercise – which then creates a vicious circle!

Many of these gut issues have a known cause. If you are suffering from any of these symptoms, seek professional advice from your sports dietitian to determine whether dietary changes can minimize symptoms and improve your energy levels.


Training without inadequate carbohydrate intake is like asking a car to run on no fuel. Carbohydrate intake needs to reflect your daily exercise load with greater amounts consumed on higher training days. Triathletes generally require approximately 5-7g of carbohydrate per kilogram of body weight. For example, a 70kg athlete may require about 350-490g carbohydrate on a training day. A simple carbohydrate counter (see basic sample below) can help you determine if you are meeting your daily carbohydrate needs.

* Carbohydrate amount will vary with individual brands/types


The timing of food intake can significantly impact training performance. Including a carbohydrate-rich snack before training can benefit training outcomes. For shorter events, it has been shown that simply rinsing your mouth with a sports drink can reduce the perception of fatigue and improve performance.

Consuming 30G-60G of carbohydrate per hour during Olympic distance triathlons and up to 60-90G per hour for longer events has been shown to optimize performance. Eating a snack containing carbohydrates and protein within 30 minutes of training can assist in recovery, particularly in cases where the next session is in <24 hours.


Inadequate nutrient intake can quickly lead to poor energy levels. In endurance athletes, there are three markers in particular that tend to require attention:

Iron – low iron can result in poor oxygen delivery to the working muscles.

Omega-3 fatty acids – inadequate levels of these reduce nervous system function and decrease blood vessel elasticity (which leads to greater inflammation potential).

B Vitamins – low levels negatively affect the body’s ability to release energy from carbohydrates, proteins and fat.

An annual blood test can help determine whether you are receiving adequate nutrients through your diet.

Adequate nutrients from fruits, vegetables, lean meats, whole grains, dairy, nuts & seeds are important for optimal body functioning. Here is a recommended :

* Individual amounts vary, particularly in the grains food group.


The effect of dehydration on energy levels should not be underestimated. Without adequate hydration, the body cannot properly transport oxygen and fuel to the working muscles and brain, regulate body temperature and allow muscle contractions to take place.

A change in body mass of 2% has been shown to decrease sporting performance by up to 10%. ‘Sporting performance’ includes factors such as earlier onset of fatigue, increased heart rate and body temperature, cramping, increased the perception of effort, and decreased mental and skill acquisition.

As a general guide, you should drink enough fluid daily so that you pass clear urine 5-6 times per day. This tends to be approximately 35-45ml per kilogram of body weight per day, but IN ADDITION to this, an athlete needs to replace sweat lost during training – this is typically 0.5-1.5 litres per hour of exercise.

For a more precise figure, a sports dietitian can measure sweat and electrolyte losses to develop a tailored hydration plan for each individual athlete. The longer the event, the more critical this becomes.

Source: 2XU 

About the writer

Ola Luczak – Accredited sports dietitian with Sports Dietitians Australia
Ola is an accredited sports dietitian with Sports Dietitians Australia and works with the Maribyrnong Sports Academy, Nunawading Swimming Club and Gippsland Sports Academy. She has also worked extensively with Knox Tri Club in the and various private triathletes of all distance events.

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