CalendarThe chances are, that as a competitor in endurance sport, you are taking some time during January and February to plan your races for the year and schedule the various blocks of training required to support that race plan.

For example, if you are a triathlete looking to race Ironman UK in August, you are likely to be starting a ‘base’ period of moderate volume, low intensity training across swimming, cycling and running, together with some strength and conditioning work. This might last 12 weeks before you switch to the ‘build’ period, upping your intensity and the frequency of your training sessions. Then it’s into your peak training period before your taper starts for the Ironman. Finally there’s a well-deserved rest. But have you considered how your nutrition needs to match these different phases of your training programme?

Nutrition periodization is the term that describes matching your nutrition intake to your training sessions. Your goal is to fuel each training session sufficiently to perform to your full potential and to recover quickly enough to be ready for your next training session, whether that’s later the same day or the following day. This means planning when and what you will eat both before and after training sessions. But it isn’t just about consuming as much starchy and sugary carbohydrate as possible to fuel your glycogen stores. Making sure you have sufficient protein and healthy fat is also important, particularly to keep your muscles, bones and joints healthy and your immune system in good working order. And don’t forget to add several servings of vegetables and fruit to ensure you have sufficient vitamins to support your various metabolic processes, such as energy creation.

Eating a good, clean diet full of nutrient rich, unprocessed food is one part of supporting your training with effective nutrition. Eating at the right times to support workouts and recovery is another. The third concerns the amount that you eat, and this needs to change throughout the season in line with your training volume. During your base training period, with low intensity workouts, you won’t require as much carbohydrate as in your subsequent ‘build’ period when you increase intensity. This is largely because most of your workouts will take place in the aerobic training zone where you can call on your fat stores for additional fuel. Whereas high intensity work uses the anaerobic energy system more frequently and calls upon your muscle glycogen stores for quickly available carbohydrate. Nor will you need as many calories as later in the season, as you are burning fewer calories while training at lower intensities. So eating less starchy and sugary carbohydrate at this time is the way to go, while keeping your intake of protein, healthy fats and nutrient-rich vegetables and fruit at a similar level year round.

Tips for consuming fewer carbs at this time include:

  • Having smaller portions of potatoes, rice, pasta, noodles, etc with your meals
  • Eating a smaller amount of bread and cereals.
  • Not eating too many energy bars as snacks
  • Avoiding cakes, biscuits, pastries and sweets
  • Matching your use of sports nutrition products to the intensity of your workouts – for example you are likely to have a lower requirement for energy gels per hour during a three hour moderately paced ride than one which includes periods of hard interval training.

If you are looking to drop body fat a little, the base training period is the time to do this. Restricting calories, particularly carbohydrates, during the build and peak periods could compromise your training.

As your training ramps up, increase your carbohydrate intake proportionately but be careful to make quality choices that will maximise your nutrient intake. Pre-training is the time to take on board sugary carbs which will give a fast release of energy, eg juices, white bread, rice cakes. Post-training, choose wholegrain breads, wholemeal pastas, quinoa and oats for slow release energy. Use starchy vegetables like butternut squash and sweet potato to add nutrients to your diet, and remember that beans and lentils are sources of carbohydrate as well as plant protein.

Jo Scott-Dalgleish BSc (Hons) is a BANT Registered Nutritionist, writing and giving talks about nutrition for endurance sportBased in London, she also works as a Registered Nutritional Therapist, conducting onetoone consultations with triathletes, distance runners and cyclists to help them eat well, be healthy and perform better through the creation of an individual nutritional plan. To learn more about these consultations, please visit