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Nutrition for Sports Performance

We've put together the following article which explains how nutrition goes hand in hand with physical exercise and the performance potential of an athlete.

The topic is huge, but we've included information which we hope will explain the fundamental areas of nutrition and help athletes understand how and why nutrition is so important

We've included a discussion thread to the right so please feel free to question, argue, or berate our ideas!

Nutrition for Sports Performance

We can follow the best training programmes, perfect our technique and give 100% during training, but if our nutrition is not right, we will fail to reach our full potential. The importance of getting ‘your’ nutrition right cannot be underestimated. Our bodies are all very different and have very different dietary demands, so unfortunately there is no ‘one size fits all’ solution. But what we can do is give our bodies a well planned, balanced nutritional intake and then assess and adjust to achieve our perfect personal nutritional solutions.

Food Groups.

The human body needs macronutrients (carbohydrates, protein and fat) and micronutrients (water, vitamins and minerals) to live, to remain healthy and in our case, to enable a high level of physical output and recovery. Macronutrients give us energy whereas micronutrients are required to ‘unlock’ this energy within the macronutrients. Macronutrients also unlock each other and this is why it is so important to eat a balanced diet – carbs fat and protein together.


Protein is fundamental to post exercise repair, and is therefore crucial for optimal performance. The body is only able to use proteins in a repair function if vitamin A is present and vitamin A is only found in saturated fats. If we consumed egg whites on a daily basis to increase protein intake, without the yoke, or other vitamin A source, the protein within the egg white would be unable to perform repair functions. Complete eggs are one of nature’s perfect recipes – fat and protein together in perfect proportions.

Proteins are made up of amino acids and can only work to repair the body if all 20 amino acids are present. The body is only able to produce 11 of these amino acids so has to ingest the remaining 9 (essential amino acids) to perform all functions. There are some food that contain all of the essential amino acids ie, eggs, meat, poultry, dairy, fish, soy foods, buckwheat and quinoa. In an ideal word we should consume one of these each time we eat, whether a snack or a meal. What we can do though is to eat combinations of other foods which contain some of the essential proteins each, but this takes a lot of planning to ensure all essential amino acids are consumed. Such foods are cereals and grains, breads/pastas, pulses, nuts and vegetables.


It is so important for an athlete’s diet to include significant levels of fat. The thought that fat makes you fat is scientifically proven to be incorrect but in fact careful management of fats is proven to significantly increase physical performance. Recent research suggests that for optimal performance, athletes should obtain 40% of their calories from fat.

Fats are split into 2 categories: saturated fats (normally from animal source), and un-saturated fats; the latter being divided into poly-unsaturated fats and mono-unsaturated fats (generally found in olives, seeds, nuts, fish etc). A general rule of thumb is that saturated fats are solid at room temperature and un-saturated fats are liquid at room temperate (ignore margarine as this is chemically altered to make it solid at room temperature – known as trans fats and really, really bad for you!)

Saturated fats are important as they transport vitamins A,D,E and K; without these there can be a huge impact on health. As previously mentioned vitamin A unlocks the repair function of protein, so is essential for athletes.

Mono-unsaturated fats are no harm to the body unless they are chemically changed by heating or by heating and adding hydrogen (the process used when making margarine). For this reason these fats should be consumed un-heated, or only when heated for a short period of time, ie stir frying. Olive oil is a great source of mono-unsaturated fat.

Poly-unsaturated fats, like saturated fats, are vital to human health and like mono-unsaturated should not be heated for long periods if avoidable. These fats are sub-divided into Omega 3 and Omega 6, both of which are required for good health, especially Omega 3. Cod liver oil, oily fish, organic eggs and walnuts are good sources of Omega 3 whereas seeds (sunflower, pumpkin, sesame etc) are a good source of Omega 6.


Carbohydrates can be our best friend and at the same time our very worst enemy. Terms such a complex carbs, simple carbs, glycemic index and gylcemic load make understanding carbs quite complicated. Once understood though, carbs are definitely an athlete’s friend and alongside a correct balance of protein and fat can truly unlock one’s full potential.

Like all of the macro nutrients, carbohydrates are splint into sub nutrients: simple carbs (sugars), complex carbs (starchy food) and non-starch polysaccerides (NSP or better known as fibre). Simple and complex carbs can be used as energy but the body is unable to unlock the calories in NSPs, although these are necessary to assist digestion.

Whether simple or complex, an athlete needs carbs for energy but consuming the right carbs at the right time is critical and will be discussed later. A really good way to understand carbs though is to look at the Glycemic Index (GI) and the Glycemic Load (GL).

Glycemic Index is a measure of how quickly carbohydrates are absorbed into the bodily system. A food with a high GI will be processed very quickly and available for energy almost immediately. A low GI food will be processed slowly and its energy will be released over a longer period of time. However, the GI of a food doesn’t always tell the whole story and may mean very little to us as athletes.

Glycemic Load can be a more informative way of looking at carbs. The GL of a food indicates the speed that the carbs are processed and how much energy there is in the food. An example, water melon has a very high GI, but contains very little energy, so the carbs are processed very quickly but there is very little energy in a whole watermelon. If looking at GI it would appear that one may wish to avoid water melon if staying clear of high GI foods, but when looking at the GL the truth would be revealed.

There are also external factors that affect the GI/GL and another reason to always eat balanced meals/snacks. • When carbs are consumed with fat, the GI of the carb is reduced. • Protein also slows down the entry of carbohydrates into the body • Fibre delays gastric entry – this is why wholegrain foods (bread, pasta etc) have a lower GI then there ‘white’ counterparts.

Vegetables are a fantastic source of low GI carbohydrates and contain many minerals and vitamins too. Pasta and rice, even wholemeal, are generally factory-processed and lack the micronutrients found in vegetables. Quinoa is a fantastic alternative to rice/pasta as it is extremely low GI and is a complete protein, containing all essential amino acids.


Minerals and vitamins have different roles but between them they are required to unlock the macronutrients (fat, protein, carbs) and are essential to good health.

Vitamins – the body can make some vitamins in small amounts but generally we get all of our vitamins from plants, or by eating meat that contains the vitamins as a result of the animal eating plants. Processed foods usually lack in vitamins but an array of fresh vegetables of different colours will be packed with vitamins. There is a list of over 100 things that vitamins do for you and you really wouldn’t want to restrict any of the functions.

Minerals are responsible for ensuring our body functions correctly (hormones, nervous system, metabolism etc). The ‘big 4 minerals’ are Calcium, Magnesium, Potassium and Sodium and we require these in greater quantities than other minerals. Again minerals are required for good health but they also unlock the energy in our diet. So if you eat the perfect balance of carbs, protein and fat at the right time, but are lacking in minerals then you will fail to achieve your physical potential. Quality and plentiful minerals are found in fresh, un-processed foods such as meat, poultry, fish, seeds, vegetables, Celtic sea salt, dairy products etc. A fresh balanced diet will provide you will all of your mineral needs.

Sources of Energy from within the Body.

The human body burns calories whilst sleeping, resting, working, exercising etc. Energy comes from carbs, fat and protein. As a rule of thumb, low intensity activities burn mainly fat and as the activity becomes more physically demanding we get more of our energy from glucose and glycogen (carbs), although still using fat and protein.

Carbohydrates. The average human body stores around 1500 calories of carbohydrates (glucose in the blood and glycogen in the muscles and liver), so at a burn rate of 1000 calories per hour, if using carbs as the sole energy source we would theoretically run out of ‘energy’ after 1hr 30 mins. This doesn’t happen, as we use fat and protein as an energy sources too, i.e. an Ironman time of 10 hours requires around 8000 calories from sources other than carbs, so we utilise fat and protein. We can also refuel whilst exercising - the body is able to absorb around 60 grams (240kcals) of carbohydrates per hour but to do so would need to ingest 80-100 grams (320-400kcals). 80-100kclas is a lot to ingest and some athletes may find this too much and get a feeling of sickness and/or bloating. As with physical training, we as athletes need to train our bodies to absorb nutrition whilst exercising. Determining the types of nutrition that suit us and the maximum quantity that we are able to absorb during exercise is key to personal nutrition.

Fat. Research has shown that, “Endurance training results in a shift of metabolism toward a greater use of fat during the same absolute and relative exercise loads. This produces a glycogen sparing that is associated with improving endurance capacity.‟ As the body uses less carbohydrates and more fat, we need to concentrate our diets with equal emphasis between fats and carbohydrates.

Even when using fat as an energy source we still need glucose/glycogen. During long, slow duration exercise (ie zone 2 training or IM race), fat can, and has to, help fuel activity, but glycogen is still needed to help metabolise the fat into a useable energy source. When we have insufficient glycogen/glucose to assist with the metabolism of fat we are unable to operate at continued performance levels and a said to ‘hit the wall’ or ‘bonk’.

Protein. The body does use protein as an energy source but protein has other functions in the human body so isn’t available to us as a pure energy source. An average adult endurance athlete requires 1.2-1.6 grams of protein per kilo of body weight per day which for a 75kg male equates to 120 grams. This is a large amount of protein and to ensure the body receives all of the protein required it is important to include protein in every meal and snack, rather than just protein rich evening meals as is traditional with Western diets. The body uses protein to fuel recovery and repair whilst we sleep. There is no need to consume protein immediately after exercise as we just need to build a reserve over the day to enable repair and recovery as we sleep.

Factors Affecting Physical Performance.

There are three nutritional factors that effect whether you are able to achieve optimal personal performance:

• what you eat
• how much you eat
• when you eat

What you eat.

The phrase ‘you are what you eat’ hits the nail on the head when it comes to sports performance; so what are you? Are you trans-fat packed, processed, butcher’s floor leftovers? Or are you fresh, mineral rich and high quality; but more importantly, which is your performance during training sessions and on race day?

The human body is exceptional in so many ways but it needs the correct fuel to remain this way and reward us with maximum performance. The body will thrive on a balanced diet of carbs, fat and protein but these need to come from fresh, good quality and un-processed sources.

How much you eat.

Every person is different and will process food in a different way. Not all calories ingested are able to be used as energy (fibre for example) and not all calories from protein and fat are available for energy as they have other functions in the body. It is therefore not practical to calculate the amount of food require by counting calories.

The human body is extremely clever and knows what it needs to function at 100%. After we eat the body takes approximately 20 minutes to analyse the food/drink we have consumed. It will look for protein (essential proteins), fat, carbs, minerals, vitamins, water and more. After 20 minutes the body will decide whether or not we have ingested all of these in adequate quantities. If we haven’t then we will get the feeling of hunger. Think of a huge Chinese takeaway where you feel you can’t possibly eat another prawn cracker. After 20-30 mins you’ll often get that feeling of hunger, when it doesn’t seem possible you can still be hungry. The body has analysed the food and decided that a Chinese takeaway contains very few of the vitamins, minerals and macro nutrients required so will give you a signal saying you are hungry. Imagine now eating a freshly prepared roast chicken with fresh vegetables and homemade gravy. Even though you may not have had a huge portion, it will be several hours before you get the feeling of hunger.

There are 2 types of ‘feeling full’. Distension is the term used to describe when the stomach is volumetrically full and the body gets the message not to eat any more to protect the stomach – this is not what we are looking for. We should aim for satiety - after 20 minutes of eating a balanced freshly prepared meal of sensible portion size, the body will analyse the food and give you a feeling of being full and is called satiety – as athletes, this is what we are trying to achieve after each meal and snack.

During high volume training the body will require more calories and the amount one would have to eat in a sitting if only eating every 4 hours may be too much and distension would be achieved prior to satiety. It may therefore be necessary to snack between meals.

When satiety is achieved the body will use the fuel over a period of time and will assess when it needs more fuel. This may be one hour, 4 hours or 8 hours. For the average person, a period of 4 hours is a good period to aim for; so we should aim to eat portion sizes that give us a 4 hour window before being hungry again. Some lifestyles do not suit a four hour pattern and some individuals chose to graze throughout the day. What is essential for all though is to ensure every meal or snack is balanced and contains fat, protein and carbs.

Everyone is very different so ‘how much to eat’ is very much trial and error, but if we aim to achieve satiety and only eat when hungry, our bodies will be getting the correct amount of calories to maintain a balance of energy, health and ultimately body-weight.

When you eat.

Although already touched on above, athletes need to plan when to eat in relation to physical exercise carefully. This can be broken down into pre-exercise, during exercise and post exercise.

Pre-exercise. The body can’t absorb protein or fat at a great rate and low GI carbs take a while to absorb. Although there are some exceptions to this rule, all exercise should be well fuelled during periods of high volume training and best practice is to eat a well balanced meal between 2 and 3 hours before exercise as this allows time to digest and settle.

It is important to start exercise hydrated and remain so throughout so the intake of water, or an isotonic drink in small quantities in the hour preceding exercise is recommended.

Whether we should take on high GI fluids/food within the 1 hour period before a race is a very individual thing and should be experimented with by individuals. The danger is that high GI foods raise insulin levels and can lead to low blood glucose levels. This can actually lead to a performance dip just at the start of a race.

During exercise. The body holds thousands of calories in fat but only around 1500 on average of carbohydrate in the form of glycogen and glucose. As discussed above an intake of 80-100 grams of hi GI carbs every hour will give 240 – 320kcals of useable energy to replenish glycogen and glucose levels. As the body holds 1500 calories of glycogen/glucose there is no need to take on carbs if exercise is less than one hour. It is far more beneficial to completely replenish these levels with post-exercise nutrition. So for exercise of periods longer than one hour, start to fuel at around the 20 minute mark and continue to do so every 20-30 minutes for the duration of the exercise. Type of fuel depends upon the activity, the individual and what is available.

Post exercise. After physical exercise the muscles are more sensitive to insulin than during exercise. Insulin effectively opens the muscles and cells up allowing intake of glucose. This sensitivity only continues for approximately 15 minutes after exercise, so it is very important to refuel with high GI food/drink within 15 mins of completion of exercise; this causes a rise in insulin levels and allows full replenishment of glycogen levels. It is then important to further refuel with a balanced meal 1-2 hours post exercise.

Pre early morning exercise. For an amateur athlete, early morning training is normally a necessity; however, it is often impractical to eat a balanced meal 2-3 hours prior to this exercise as would normally be advised.

A solution to this is to eat as late the night before. But there are 2 variables here that athletes have to play with: what you eat and how late you can eat it.

The body stores carbs as fat if not used, and essentially, the speed at which is does this after consumption is determined by the food’s glycemic index (GI). There is a good probability that high GI carbs would be processed quickly and not used and would therefore be stored as fat very quickly afterwards too – no good to us for early morning fuel.

Low GI food is processed slowly by the body and if not used sits around for a while before being stored as fat. It is a personal thing, but you need to find a low GI food that ‘you’ can eat late at night and still sleep well on. This food will then be released as energy whilst sleeping, especially if eaten with protein as a release inhibitor. These carbs can be combined with pure protein or leafy vegetables to make them more palatable. A protein example is cottage cheese, which will repair the body overnight and complement the carbs. Fat doesn’t normally sit too well though late at night, but again, this is a personal preference.

Low GI carbs for late night consumption:
Oatcakes with cottage cheese. Wholemeal Pita Bread stuffed with lettuce and/or cottage cheese
Quinoa (cooked in advance with a stock cube and served cold with leafy salad works well at night)
Roasted sweet potato
Mashed sweet potato cold with cottage cheese
Porridge – with no sugar, honey or fruit

To compliment the late night meal, carbs should be consumed during all early morning sessions even if less than 1 hour in duration.

Ways to Improve Nutrition for Personal Performance

Nutrition can prove very complex and the biggest rule is to plan ahead to ensure there is food available and in balance for all meals and snacks. Below is a list of ‘rules and ideas’ that will guide you through the nutritional minefield:

• Eat something for breakfast, even if it’s not first thing

• Eat carbs, fat and protein as part of every meal and snack (it’s hard to get the protein in! Eggs, bacon and tomatoes for breakfast – snack banana and full fat milk blended with pure honey)

• Avoid high GI food and fat together (High GI: mashed potato, white bread, bagel, breakfast cereal, sweets, rice cakes, potato, white rice etc)

• Eat a balanced meal/snack 2-3 hrs before exercise if possible, if not, eat or drink during exercise.

• Only take nutrition during exercise if over 1 hr or if you’ve been unable to eat 2-3 hours before

Consume high GI food within 15 mins of completion of exercise, still trying to avoid high GI and fat together (chocolate for example is not great, bagel is great but not with butter on etc)

• Within 2 hours of exercise, eat a balanced meal – protein, fat and carbs included

• Do not feel obliged to eat if you’re not hungry (except breakfast), it’s your way of learning portion size. Ideally you should be hungry every 4 hours with snacks to lengthen these gaps if 4 hours doesn’t fit around meal times.

• Exercise may necessitate larger portion sizes to keep the 4 hour window; lots of exercise with require snacks between meals

• All snacks should contain fat, carbs and protein too • Avoid processed foods, due their imbalance of macronutrients, minerals and vitamins in addition to high levels of salt

• Don’t use margarine (even olive oil marg), butter is so much better if uses sparingly – cooking, spread etc (oil that is turned into a solid is converted into a form that the body doesn’t recognise or is able to process so it sends it straight to fat storage and doesn’t really get used for anything positive – know as trans fats)

• Only use olive oil for cooking if cooking time is less than 5 mins

• As a rule of thumb, avoid anything labelled as ‘low fat’ or ‘reduced calorie’ - these foods are imbalanced and frequently have harmful additives to maintain taste

• Eat whole foods where possible – perfect balance of macro and micronutrients, ie eggs

• Obtain carbs from vegetables where possible rather than starchy carbs (pasta, rice, potatoes, bread – even wholemeal varieties) Curry on a grilled veg base instead of rice as an example

• Eat quinoa instead of starchy carbs, tastes like them but great source of complete protein

• If eating starchy carbs, eat in moderation and increase meat / sauce proportions

• Carefully manage consumption of high GI/GL foods other than directly after exercise and even then, avoid high GI and fat ie chocolate 9insulin levels increase absorption of fat)

• Stay hydrated at all times • Eat salt – real salt, Celtic sea salt ( sticky and grey in colour – health stores or internet sourced, not supermarket) – there is less need to restrict intake as it’s not all sodium, so not so bad for you

• Use full fat milk, skimmed milk is nothing more than grey water from a cow dyed white. Full fat milk is 3% fat compared with 0% for skimmed. (3% fat = 7.5ml of fat per 250ml glass, = 67.5 calories – not that we care about calories). Skimmed has little or no calcium, little or no protein, and no fat

• Don’t be scared of saturated fat, animal source or palm/coconut oil

• Monounsaturated fats are ok, but do not cook with them at high temps (olive oil, veg oil, rapeseed oil, nuts seeds) Avoid if in solid form

• Polyunsaturated fats are good as long as they are in their pure form, ie liquid (not bombarded with hydrogen and heated to make them hard and turn them into trans fats that your body doesn’t recognise and sends straight to the fats cell for storage)

• You need polyunsaturated oils for Omega 3, so eat oily fish once or twice a week (no more due to mercury content) Organic eggs are rich

Tiger Frog Nutritional Analysis

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