For the first 90-120 mins of an endurance or ultra endurance event, muscle glycogen is the main source of fuel. With a little help from blood glucose and fat from stores within the muscle and elsewhere in the body, you have you all your fuel needs for training and competing. Or do you?

As exercise duration increases, the muscle glycogen stores become depleted and fat oxidation provides a higher proportion of the energy needs. Whilst the fat supply may well be quite large, and could fairly easily fuel the body for days, the problem lies in how long it takes for energy to be released from fat. Therefore, it makes sense to increase the muscle glycogen stores to the highest possible level prior to any endurance event, the longer the event the more important it becomes, and it’s this with the intake of of carbohydrate during such events, that are critical for optimal performance.

STRATEGIES TO OPTIMISE ENDURANCE OR ULTRA-ENDURANCE TRAINING

Carbohydrate Loading

Carbohydrate loading is a technique used prior to an endurance event to enhance performance. High-carbohydrate foods or drinks, or even both, are ingested on the days leading to an event to increase the stores of muscle glycogen (carbohydrate) in the muscles. It’s recommended that you should be aiming to eat a high-carbohydrate diet for 3 days (500-600g of carbohydrate daily, or 7-10g/kg per day) prior to any endurance events. However, it has been shown that in highly trained athletes even 3 days of carbohydrate loading is longer than needed to maximise muscle glycogen stores. By ingesting 10g/kg of carbohydrate daily, maximal muscle glycogen concentrations can potentially be attained within just 24-36 hours.

Types of carbohydrate for optimal muscle glycogen restoration

Any high-carbohydrate, low-fat food or drink, can be used as part of a high-carbohydrate diet to optimise the rate of muscle glycogen. The same applies when it comes down to restoring your muscle glycogen for daily training. Among suitable food items are bread, rice, pasta and potatoes. Potatoes have a high glycemic index, making them an ideal food type to include in a diet aimed at rapidly restoring muscle glycogen for training.

As well as prior to endurance events, you should be aiming for a high carbohydrate intake as part of a normal diet as it helps to replenish glycogen stores from one day of training to the next. To achieve this, nutrient-rich carbohydrate foods should be chosen and added to other foods in order to provide a good source of protein and other nutrients, such as minerals and vitamins.

Poor training performance, unexpected fatigue, frequent illness, or failing a specific training session may be indirect signs that the carbohydrate intake isn’t suitable for your needs. Further difficulty arises when you are looking to lose a little weight and reduce your body fat levels, as this requires moderate energy restriction and therefore a lower carbohydrate intake. You can solve this by periodising the nutritional goals and carbohydrate intake. For example, during out of competition training periods you could have a lower carbohydrate intake for weight loss, whereas you would look to increase the carbohydrate intake for competition preparation and during recovery to optimise your glycogen stores.

Practical ways to increase carbohydrate intake

• Increase the number of meals and snacks throughout the day. Plan your nutrition ahead so that snacks are always available during the day

• Make carbohydrate-rich foods the basis of each meal and snack, e.g. bread, pasta, couscous, noodles, potato, rice, crackers, fruit

• Time your intake around training. Include a recovery snack containing carbohydrate shortly after the training session, and if possible aim to have a meal approximately an hour later

• Reduce foods that are high volume and may be limiting your appetite. This may mean replacing some wholegrain foods with lower fibre alternatives. Dried fruit can be added to cereal and porridges

• Include carbohydrate/energy-rich fluids. Ensure that all fluids contribute to your energy needs. You can do this by replacing diet drinks and large volumes of water with sports drinks, juices, or fruit smoothies

• Include condiments, e.g. jam, honey and sugar, to increase energy intake without adding much volume

Individualised Carbohydrate Intake

Each type of endurance, or ultra-endurance event, will present a unique set of nutritional challenges when it comes to rehydrating and refuelling during training. A pre-exercise meal or snack should contain enough fluid to maintain hydration, be relatively low in fat and fibre to help with gastric emptying, be high in carbohydrate to maintain your level of blood glucose and maximise glycogen stores, and contain a moderate amount of protein. Most importantly though you need to be familiar with whatever you are choosing.

For meals consumed 3-4 hours prior to exercise the amount of carbohydrate intake that has been shown to enhance performance ranges from 200-300g. Below are examples of pre-exercise meals and snacks.

• Cup of oats or cereal with low-fat milk or yoghurt (you could add sugar or honey)

• Crumpets or pancakes drizzled with honey and yoghurt and served with fruit salad

• A couple of slices of toast with scrambled egg and a glass of fruit juice

• Liquid meal replacement containing at least 30g of carbohydrate

• A sports bar that is low fibre and low fat, with a cup of fruit juice or energy drink

Protein requirements during training

Protein is a key nutritional component for those involved in endurance training. It’s definitely not something to neglect. It’s suggested that endurance athletes need more protein than the Recommended Dietary Allowance, which frankly is too low anyway. The current recommendations for daily protein intake during hard endurance training are 1.2-1.7g/kg per day, with the higher value during periods where the training load has increased. The targets for your protein intake must take into account your requirements, goals and training programme. Generally though, protein requirements can easily be met through a healthy balanced diet. Adding lean protein e.g. skinless chicken, fish, lean meat, legumes, eggs, and low-fat dairy to meals and snacks will ensure that optimal protein intake can be relatively easily achieved. Below are examples of foods containing at least 10g or more of protein.

• 40-50g lean meat, skinless chicken, fish, low-fat cheese or nuts (bear in mind that nuts are high in fat and should be limited if calorie intake is to be limited for weight loss purposes)

• 2 eggs

• 300ml low-fat milk or yoghurt

• 1/2 to 3/4 cup dried beans, lentils or split peas

It is important that protein intake does not replace your carbohydrate intake in order of importance, and there appears to be no reason for your protein intake as an endurance athlete to be above 2g/kg per day.

Effect of protein on exercise performance and post-exercise recovery

Optimising performance and recovery after exercise is a big challenge. Your protein intake, particularly if it contains the branched-chain amino acid (BCAA) leucine, may further improve performance levels and the rate of recovery from training and any events.

Protein ingested together with carbohydrate is super effective at increasing the rate of muscle glycogen. Supplementing with a whey, casein or soy protein powder, are often recommended to be used by athletes.

Carbohydrate and protein intake to optimise training

Ingesting protein together with carbohydrate within 1 hour after completion of your training, may help with recovery. Many studies have utilised 0.8g/kg of carbohydrate ingested with 0.2-0.4g/kg of protein. Alternatively, there have been a number of studies that have shown positive effects when chocolate-flavoured milk has been ingested after exercise. Post-exercise recovery supplements containing protein and carbohydrate, and other types of protein-containing snacks may also be ingested. The following examples provide about 50g of carbohydrate plus more than 10g of protein.

• 250-350ml carbohydrate energy drink and 250ml liquid meal supplement containing more than 10g of protein per serving

• 250-350ml smoothie made with fruit, low-fat yoghurt with added honey

• 250-350ml milkshake or flavoured milk drink

• 250ml fat-free/low-fat fruit yoghurt or 350ml drinking yoghurt

• A sandwich with lean protein filling e.g. reduced fat cheese/egg/chicken and 1 fruit

• Cereal with low-fat/fat-free milk

• 1 Protein bar with a cup of fruit juice

• 500-750ml carbohydrate energy drink, cold drink or fruit juice, with a protein drink

ACHIEVING A LOW(ER) BODY FAT PERCENTAGE

A balanced long-term weight loss strategy is crucial if you want to reduce body fat and weight. The main aim should be to promote a moderate energy deficit whilst maintaining adequate intakes of nutrient-dense carbohydrate, lean protein and essential micronutrients to maintain optimal performance, recovery and health.

A sensible weight loss goal of about 0.5-1kg of body fat per week should be achievable with an energy deficit of around 500-1000kcal per day.

Your daily energy deficit can be achieved by making changes to existing eating habits, such as portion sizes, following a personalised diet, by increasing energy expenditure, or by a combination of all these strategies. For any nutrition plan to be successful, it needs to be something that you can adhere to with ease. It needs to be practical and easy to follow in all situations, i.e at home, work, travelling and when eating out.

It is generally recommended that for females, energy intake should not be lower than 30-35 kcal/day per kg of fat-free mass, plus the energy cost of your training. If you go for a low-calorie eating plan, less than 1500 kcal/day, care should be taken due to the risk of insufficient micronutrients. Diets that provide 400-600 kcals and less than 100g of carbohydrate per day are not recommended as the side effects may include such dehydration, glycogen depletion, nausea, headaches, light-headedness and loss of lean body mass, all of which aren’t ideal for optimum performance, or training.

For light and moderate training I would recommend a carbohydrate intake of 3-5g/kg, increasing to 6-8g/kg during times when the training is intense, or the volume has increased. It’s important to give priority to nutrient-dense carbohydrates such as wholegrain cereals, porridges, breads, rice, pasta, potatoes and starchy vegetables, fruit and low-fat dairy products, rather than energy-dense carbohydrates such as cold drinks, sports drinks, energy bars, sugar, jam, and sweets.

Alongside your carbohydrate intake I would look at a protein intake of 1.2-1.7g/kg, aiming for the upper level if there is a substantial calorie restriction, this will help to maintain lean body mass and promote satiety.

Don’t completely exclude fat from your diet as it is needed for insulation and protection, as well as for fat-soluble vitamins and essential fatty acids. However, fat is extremely energy dense, 1g of fat equals 9 kcals, therefore it should be limited to 1-1.5g/kg per day, or less than 30% of your total calorie intake.

Practical dietary strategies to lower body fat

Plan ahead

• Plan regular meals and snacks in advance to encourage healthy eating habits

• Use meals, such as breakfast or dinner, as a post-recovery meal instead of adding additional calories in the form of an additional snack or meal

Manage appropriate portion sizes

• Eat regularly as it helps to keep blood sugar levels stable and helps to prevent over-compensation at meal times, or snacking on ‘unhealthy’ food

• Buy pre-portioned snacks to prevent over-eating

• Keep unhealthy foods and snacks out of sight. If they are visible you are more likely to eat them

• Once food is plated, if there are any leftovers store them in plastic containers and keep them out of sight

• Increase your fibre intake by choosing whole wheat grains, breads and cereals, legumes and bulk up your meals with ‘free vegetables’ such as lettuce, cucumber, tomato, broccoli, cauliflower, peppers. This will help to add volume to your meals, providing a feeling of fullness, all without adding too many extra calories

• Consuming lower glycemic index carbohydrates such as sweet potatoes instead of regular potatoes, will help to keep you fuller for longer

• Make sure each of your meals contain a mixture of carbohydrate, protein and a small amount of fat

• Try to eat slowly. Putting your knife and fork down between mouthfuls can be helpful

• Ensure portion sizes are reduced appropriately when tapering your training

Keep fat intake in check

• Choose healthier cooking methods such as baking, steaming, grilling, and boiling. Avoid food that has been fried, deep-fried or grilled in a lot of butter or oil

• Change any intake of dairy products to low-fat or fat-free

• Adapt recipes and use reduced-fat ingredients to reduce the calories within each meal

• Choose low-fat sauces such as tomato-based sauces instead of mayonnaise-based sauces and dressings

• Choose lean protein sources. Trim the visible fat off meat and remove the skin of chicken before cooking

• Choose snacks with less than 5g of fat per 30g of carbohydrate

Limit calorie-dense foods and drinks

• Drink mainly water to satisfy fluid requirements

• Dilute fruit juices and cordials with water

• Limit refined carbohydrate such as soft drinks, sports drinks, gels or sweets for training purposes only

• Limit alcohol to 1 unit (females) to 2 units (males) per occasion. Stretch alcohol intake by adding ice, water or soda to drinks, or choose the light/non-alcoholic option

Manage social activities

• Choose restaurants that provide healthier options. Most restaurants now show the calories contained within their meals on the menu, or you can check online before hand.

• Order smaller options. You could be weird and order two starters as a main meal

• Start meals with a salad

• Make healthier choices by avoiding creamy foods and ask for the dressing on the side

NUTRITION TO ENHANCE IMMUNITY

There is plenty of evidence that there is depression of the immune system lasting from 3 to 72 hours after training. During this time, there is an increased risk of contracting minor illnesses or infections, which may then cause interruptions to your training or worse case scenario, under-performance in your chosen event. Post exercise immune depression is most pronounced when 90 mins or more of prolonged exercise at moderate to high intensity (55-75% VO2) has been undertaken with no food (carbohydrate) ingested after the exercise.

To help maintain an effective immune system there are some strategies that have been shown to help.

General recommendations to decrease risk of illness

• Keep life stresses to a minimum

• Avoid over-training and chronic fatigue

• Ensure you get enough sleep and try to keep a consistent sleep pattern

• Eat a well-balanced diet to avoid deficiencies and ensure you have an adequate intake of carbohydrate, protein, fluid and micronutrients. Especially iron, zinc, and vitamins B6, B12, C and E

• Avoid a dry mouth during training and at rest

• Before important events, avoid sick people and large crowds whenever possible

• Ensure you consume a carbohydrate intake of 45-60g/hour during 90 mins or longer high-intensity exercise sessions

• Supplement with a good multivitamin and mineral to support a calorie restricted diet, such as during weight loss phases, when travelling, or when a variety of fresh fruit and vegetables is limited

• Possibly supplement with probiotics when travelling; iron supplements should not be taken during periods of infection

• Practice good hygienic principles, e.g. wash hands regularly, don’t share water bottles, cutlery and towels, and be sure to clean bottles well after each use

• Avoid rapid weight loss

KEY SUPPLEMENTS FOR ENDURANCE AND ULTRA-ENDURANCE TRAINING OR EVENTS

Broad-spectrum multivitamin and mineral supplement

• Offers support for those following a weight-loss diet of less than 1900 kcal for women or 2300 kcal for men

• If no deficiency is present, it may not improve performance

Single-nutrient supplements (e.g. calcium, vitamin B12, iron)

• Will not correct a poor diet

• Only recommended if your diet cannot supply an adequate intake, or if a deficiency has been established

• Calcium supplementation may be recommended for treating or preventing osteoporosis or bone stress injuries. However, calcium without adequate oestrogen/progesterone status cannot guarantee bone status improvement

• Supplementation with certain vitamins or minerals may cause side effects, such as constipation

• Excessive intakes of some vitamins may impair the absorption of other nutrients

• High intakes of some vitamins can be toxic

Liquid meal replacements

• These can be convenient, low in bulk and can be used for a pre-event meal, post-exercise recovery or to supplement a high-calorie diet in situations where you may lack an appetite or suffer from gastro intestinal disturbances

• Lactose-free options are available for those with lactose intolerance

• Over-reliance may lead to a lower intake of whole foods

• Risk of contamination with banned substances

High-carbohydrate supplements

For example, sports drinks, high-carbohydrate sports drinks, soda drinks, powders, sport bars, cereal or breakfast bars, sport gels.

• Can help meet high carbohydrate requirements, for example during periods of high volume training or carbohydrate loading, before, during and after exercise, or in cases where you may lack an appetite

• Overuse may lead to weight gain

High-protein supplements

For example, protein powders and bars.

• Recommended if you are not able to meet protein requirements

• When added to carbohydrate sources it can be used for recovery

• Can be expensive. Milk is an economical alternative and ideal drink for recovery, or if you lack an appetite

• May lead to a lower intake of whole foods or carbohydrates

• Protein overload may lead to excess body fat storage

Prebiotics and probiotics

• Promote gastrointestinal function and have benefits if you suffer with irritable bowel syndrome, or end up on a course of antibiotics.

• The immune benefits are not yet truly established.

Caffeine

• Caffeine ingestion prior to exercise may have performance enhancing effects by decreasing the perception of effort and fatigue. A small to moderate dose of 1-3mg/kg of caffeine shows the maximal benefits

• Further research and testing is needed to define the range of caffeine protocols

• Foods and drinks that may contain caffeine include coffee, tea, soft drinks, chocolate, energy drinks, sport supplements and chewing gum

• Caffeine can cause nausea, trembling, nervousness, headaches, insomnia and diarrhoea at high doses

IN SUMMARY

It is clear that to maintain optimal training for endurance events a diet high in carbohydrate foods should be ingested to maintain muscle glycogen, and there are clear benefits from carbohydrate loading prior to such events and carbohydrate ingestion during them, there is no doubt that a post-exercise intake of protein alongside carbohydrate will help to increase recovery and reduce DOM’s.

As an endurance athlete your diet should predominately be made up of carbohydrate to make sure that you have plenty of energy to train and perform to an optimal level. This is also to ensure that your muscle glycogen stores don’t become too depleted, which can all too easily happen.

As you can see from the table below, the generally accepted recommendations for carbohydrate intake is a lot and it will likely be a struggle to achieve, without making a few alterations to your diet. You also need to understand that your gut will need to be trained to be able to tolerate such high carbohydrate intakes, especially during training for an event.

An important point to make note of is that if your carbohydrate intake is low, or if your protein intake isn’t ideal, you want to focus on these aspects of your diet first. Always keep in mind that you want to fuel for your sport and diet around it. Focus on adequate fuelling first and it’s likely that the desired body composition will follow.