Eating for Endurance by NutritionWise

   Eating for Endurance – "The Training Diet"

What we eat and drink, affects our day to day stamina, long term health, weight, body composition, exercise and recovery time. Nutrition is the ultimate ergogenic aid and if you are serious about your sporting performance it should be a core part of your training regimen. Your training period is the time to experiment with fuelling strategies for competition, finding out what suits you and enabling you to tailor a nutrition plan to your individual needs. So, if diet is something you have neglected thus far, and you want to optimise exercise performance, read on...

  Energy

We need energy from our food to keep us going in day to day activities, and in sports. However, you also need to ensure that the total energy you eat is balanced against that used up by your training: too much energy leads to weight and body fat gain which may negatively impact your performance. On the other hand, too little energy intake during periods of intense training can lead to loss of muscle mass, increased risk of fatigue, injury, illness, brittle bones and for women, may cause menstrual dysfunction. With this in mind, you can say that sustaining your body's energy requirements may somewhat prevent the development of hazardous conditions that may require the use of your health or life insurance to pay for certain expenses. If, up to now, you have relied on appetite to dictate when and what to eat, you may find your performance has suffered. Such a strategy does not ensure correct balance of nutrients to maximise performance. It’s therefore worthwhile planning a nutrition regimen according to your specific body size and training goals.

The macronutrients carbohydrate, protein and fat, which are the basic building blocks of the diet, are the three main energy sources for exercise. Whilst carbohydrates are the most efficient form of energy for the body, and therefore are central to a successful endurance sports nutrition regimen, it’s vital to get the balance right between all three macronutrients.

  Carbohydrate – your muscles main fuel

Carbohydrate is the most efficient form of energy for the body and the major fuel for high intensity endurance exercise. Carbohydrates foods are all broken down into glucose during digestion. Glucose is stored in the muscles as ‘glycogen’ and it is this store that fuels your muscles during exercise. The levels of glycogen in your muscles are directly related to your diet. Regrettably, we don’t have a never ending store of glycogen in the body. In fact, a typical athlete can only store up to 2000 calories (approx.) of energy as carbohydrate, versus a competitive requirement of 2,800 calories for a marathon or 5000-10,000 calories per day for ultra-endurance events. Endurance and ultra-endurance exercise beyond 2-5 hours (e.g. triathlons and ultra-endurance cycling) clearly place large pressure on carbohydrate stores. When your muscles own supply of energy runs out, your body relies on blood glucose to top up your energy stores. This emphasises the importance of eating sufficient carbohydrates before, during and after training to provide glucose to the exercising muscle, prolong performance and enhance recovery time.

Athletes are frequently found to have inadequate intakes of carbohydrate which, during prolonged exercise, will result in nausea, light-headedness and onset of fatigue.

  How much carbohydrate should you eat?

Table 1 outlines carbohydrate recommendations which are dependent on body weight and training schedule. For instance, a typical 70kg athlete training at high intensity for over 60-90minutes and up to 3 hours, should aim to eat anywhere from 490 to 700g of carbohydrates on training days. What level they eat within the 490-700g depends on factors such as the entire length of training, the intensity throughout, the athlete's body composition and their individual eating habits. And those who are aiming for 4 or more hours of training need to be reaching 10g per kg body weight level. This level of carbohydrate intake requires careful planning, particularly for those of you trying to fit in training around your full time work, commuting and family life.

It is therefore useful to adopt a grazing type eating pattern, with plenty of nutritious carbohydrate snacks between regular meals that are based around carbohydrate foods such as bread, cereal, potatoes, pasta and rice, in addition to all sorts of beans, peas and lentils, fruit, and low fat dairy products. This may mean you have to eat up to 8 times a day so organisation and thinking ahead are key! Rest days are vital for the athlete in training, not only for recovery of muscles but also to allow maximum replenishment of glycogen stores. On your rest days an intake of 5g per kg body weight is sufficient. However, pre competition days you will need to be looking at carbohydrate loading – but that is a whole extra area that will be covered in future articles.

Table 1. How much carbohydrate should you eat?

Hours of training daily Carbohydrate requirements

1 hour per day 5-7g/kg/day

1-3 hours per day 7-10g/kg/day

4 or more hours daily 10-12g/kg/day

  What type of carbohydrate should you eat?

Carbohydrate foods can generally be thought of as starchy (bread, cereals, potatoes, pasta, rice) or sugary (juice, sugar, sugary drinks, jam, jellies, biscuits, cakes). The starchy carbohydrates, especially the wholegrain versions, are packed with vitamins, minerals and fibre and form the basis of any healthy eating plan. On your rest days get the wholegrain options in (e.g. muesli, porridge, wholegrain bread, basmati rice). However, wholegrain cereals or wholegrain breads are not suitable foods to eat just before a training run as they are high in fibre and take longer to digest and may lead to ‘runners trots’ or cramping. Before training you are better to choose the lower fibre cereals and white or wholemeal breads as these are easier to digest.

Don’t even try to meet your carbohydrate daily training requirements of 7-10g per kg weight on cereals, bread, potatoes, pasta and rice alone. You will need to incorporate some sugary carbohydrates. Sugary foods, other than fruit juice, are generally poor sources of vitamins and minerals and are therefore not features of the typical healthy eating diet. However, they are an effective addition for the serious athlete who needs compact forms of carbohydrate to meet their high demands for energy. Carbohydrate containing fluids such as fruit juices and sports drinks also make a significant contribution to total carbohydrate intake without added bulk. And don’t forget your fruits: fresh, tinned and dried, they contain natural sugars which are a very useful way to get extra carbohydrate into your daily training diet.

Richelle Flanagan, BA, MSc, PgCert Allergy, MINDI is a Sports Dietitian whose clinic is based in Dublin and works across a broad range of athletes including marathon runners, ultra marathon runners, cyclists and team sports such as Gaelic football, and is currently working with Bohemians football club. She is the co-founder of NutritionWise, the nutrition consultancy , and works with her

colleague Joanne Corbett, BSc, DBS, MSc, MINDI, who sees athletes in her NutritionWise clinic in Cork. If you would like to see a Dietitian just phone to make an appointment: Dublin: 01 2964890 richelle@nutritionwise.ie; Cork: 086 3961860 email: joanne@nutritionwise.ie. 

Endurance: The ability or strength to continue or last, despite fatigue, stress, or other adverse conditions; stamina