Sports Nutrition: Don't miss a trick!
Considering how seriously many people take their sport and how much they are willing to spend on new equipment in an attempt to etch out a little extra in performance, it’s surprising how little consideration the majority of sports men/women give to the food they eat, the amount they eat, and when they eat it!
Even at professional and semi-professional level, numerous studies over the last decade have shown that many athletes overlook nutrition when analysing their performance and ways in which they can improve it.
It’s probably easy for you to relate to the importance of good nutrition to endurance sports such as long distance running, or team sports such as rugby, but how many of the golfers amongst you consider the effects of poor nutrition as you tire, towards the end of what could have been a great round?
Let’s be clear, I’m no nutrition expert, but my aim with this blog is to simply give you something to think about. To outline a few key aspects of sports nutrition that will hopefully encourage you to at least consider how the food you eat affects your performance and just as importantly how well you recover.
Sports nutrition is relevant to any sport, at any level, but it has to be individualised. Each and every one of you has different needs, no one cap fits all.
Let’s start by looking at the different types of nutrients that make up the food we eat. Collectively they are known as macronutrients and include carbohydrates, proteins and fats. All three are required for energy, and all three, in the right quantities, are equally important to your diet.
Carbohydrates are your most important fuel for energy. But, before you rush out and eat loads of carbs, remember that (a) they come in both healthy and unhealthy sources and (b) what you eat but don’t burn off, is stored in your body as fat!
Healthy sources include whole grains, fresh vegetables, fresh fruit, beans, peas, cous cous etc, while unhealthy sources are found in things like white bread, white rice, pastry and cakes.
Each gram of carbohydrate contains 4 calories (4 kcal) which is useful to know when it comes to working out your daily allowance and portion size. Once consumed, the carbs you eat are broken down and stored as glycogen in your liver and muscles, any excess is stored in your adipose (fat) tissue.
“Fats are an essential part of your diet”
Although each gram of fat contains 9 kcal, more than double that of carbs and proteins, they are still an essential part of your diet. Not only are fats a rich source of energy, but they also surround and protect your vital organs, they are your body’s insulation, they provide essential fatty acids, and are an essential part of your brain and nervous system tissue.
Just like carbs, there are both good and bad sources of fat. Ideally you should get the majority of your fat from unsaturated sources; Omega 3 fatty acids in particular are great for your health.
Fats - The Good, The Bad and The Ugly!
Like carbs, each gram of protein contains 4 kcal of energy and as they are the most satisfying nutrient they help you feel fuller for longer. Proteins are essential for growth and repair of tissues. The more you exercise the more protein you need, and the more protein you eat the more fluid you need.
"ATP is to you, what petrol is to your car"
Understanding where your energy comes from will help when you start thinking about what to eat and when to eat.
Adenosine Triposphate (ATP) is the energy currency within your body. ATP is to you, what petrol is to your car. The more you exercise the more ATP you require. Eating a well-balanced healthy meal, with the right proportions of carbohydrates, proteins and fats, is your body’s equivalent to filling your car up with Shell V-Power Nitro+!
Your body has three ways of producing ATP; the ATP-PC system, the anaerobic system and the aerobic system. Each one produces ATP, but in different amounts and at different rates.
Your ATP-PC system provides the energy you need for brief periods of intense activity like a short sprint, a single jump, or a maximum lift.
Your anaerobic system produces energy from the breakdown of carbohydrates and kicks in after about 30 seconds of high intensity exercise. Like your ATP-PC system however, your anaerobic system can only provide a short burst of energy for a minute or so.
Your aerobic system produces energy from the breakdown of both carbohydrates and fats. It cannot produce energy as quickly as either the ATP-PC or anaerobic systems, but it’s a slow burner and will continue to produce the energy you require to keep going long after the ATP-PC and anaerobic systems have bailed out.
”Carbs come in many different forms and include sugars, fibres and starches”
Let’s have a closer look at carbohydrates. Also called saccharides, carbs come in many different forms and include sugars, fibres and starches. Monosaccharides have only a single sugar molecule (glucose, fructose), disaccharides have two sugar molecules (sucrose, lactose), and polysaccharides have over 10 sugar molecules (starch, glycogen).
When you eat carbs, they are broken down into their simplest form by your small intestines, so your muscles don’t really care if you eat good carbs or bad carbs. Simple sugars (monosaccharides) however, are broken down very easily and not only cause a spike in your body’s blood sugar levels but can also lead to serious health issues such as diabetes.
Starches (polysaccharides) on the other hand, are much harder for your body to break down, and therefore release energy at a slower more sustained rate.
I know from personal experience that once you start exercising you naturally want to eat more, but be warned, it’s very easy to vastly overestimate the number of calories you burn off during exercise and therefore the amount you can eat for the remainder of the day.
For example: A 75Kg male, runs at moderate intensity for about 1 hour per day. From the table below, his daily carbohydrate requirements are 5-7g per Kg of bodyweight (BW). Therefore, his daily carbohydrate requirements are between 375g and 525g per kg BW.
(75x5 = 375g: 75x7 = 525g).
Moderate intensity exercise is usually regarded as exercise during which you are able to talk but probably not sing. Vigorous exercise is considered as exercise during which you would only be able to say a few words before stopping to catch your breath.
When you’re exercising you will know when your glucose levels start to drop because your muscles will suddenly start to feel tired and heavy and your concentration and motivation will probably ebb as well. Protein from your muscles may then be broken down and converted to glucose. If you’re aiming to get bigger, stronger, fitter, you obviously want to avoid losing muscle protein so it’s really important to eat the right carbs and the right amount of carbs at the right time.
"the quality of the Carbs you eat has a significant effect on your blood glucose levels"
Glycaemic Index (GI)
As I mentioned earlier, the Carbs you eat are ingested and absorbed at different rates. This has a significant effect on your blood glucose levels and is known as the glycaemic index (GI) of the food. Foods are generally categorised as low, medium or high GI. When eating a high GI food (chocolate, sugar, white bread, white rice etc.) your blood sugar levels peak very quickly and then plummet! In contrast, whole grains, unripened fruits and leafy vegetables give a much slower release of glucose into the blood stream, maintaining your energy levels for much longer. There are times when you may need that sudden blast of glucose, but generally speaking, a diet rich in good carbs will help you train harder and longer.
To throw another curve ball, not all fruit and vegetables are a healthy source of carbs either. Allowing fruit to become over ripe, or over cooking your vegetables, can significantly increase their GI. One way of combatting the spike in your blood glucose levels is to combine your carbs with proteins. For example, eating a portion of almonds (low GI) straight after a banana (high GI) can really help to smooth out the effect of the high GI banana.
Glycaemic load (GL) takes into account not only the Glycaemic Index (GI) of the food you eat but also the amount of carbohydrate in a given portion.
For example; an 80g portion of pineapple which has a GI of 66 and contains 8g of carbohydrates has a glycaemic load of (66 x 8) / 100 = 5.28. Whereas, a small 205g tin of baked beans which has a GI of 48 and contains 31g of carbohydrates has a GL of (31 x 48) / 100 = 14.88.
A portion of food with a GL less than 10 is considered low, greater than 20 is considered high and anything in between is considered moderate. Similarly, a daily intake GL below 80 is considered low, above 120 is considered high and anything in between is considered moderate.
Although fibre isn’t digested, it still has many positive health benefits. For a start it helps to keep your digestive system healthy and prevents you becoming constipated. It also slows down the digestion of the carbohydrates you eat and therefore moderates the rise and fall of your blood glucose levels. The Department of Health recommends you eat 18 to 24g of fibre every day.
The aim of carbohydrate loading is to maximise your glycogen stores prior to an event and is something you should certainly consider if your activity is is likely to involve greater than 90 minutes of continuous activity.
Carb loading has been shown to delay the onset of muscle fatigue by up to 20% and improve performance by as much as 3%. There are many different carb loading strategies, too many and too complex to go into great detail here, but the table below will hopefully give you an insight in to how you can carb-load in the week leading up to an event, marathon, long cycle ride etc.
"There are 21 different amino acids which you could consider like letters of the alphabet"
All proteins are made up of a combination of amino acids. There are 21 different amino acids which you could consider like letters of the alphabet. In much the same way as all words in the dictionary are made up of a combination of letters, all proteins in your body are made up of a combination of amino acids.
There are three main groups of proteins; essential, non-essential and branched chain amino acids. Your body can produce non-essential proteins itself but essential proteins you must supply by your diet. The final group, branched chain amino acids, make up 1/3rd of your muscle protein and are therefore really important to sports nutrition.
Proteins provide 10-15% of your energy during aerobic activity and are fundamental to the growth and repair of tissue. Amino acids travel to your liver where they are used to produce new proteins. Excess is stored either as glycogen in your muscle tissue or as fat in your adipose tissue.
In a fasted state when you haven’t eaten for a few hours, amino acids can be sent back from your muscles to your liver and converted to glucose for use as energy. This is the main reason why it is not as good an idea as many people believe to exercise without eating anything first thing in the morning. Especially, if your aim is to build muscle! You may burn fat, but you may also lose protein from your muscles. If you really want to burn fat, consider high intensity interval training (HIIT) instead.
Take a look at the following table for an idea of what your daily protein requirements are. What is apparent is that the more you exercise the more protein you need, up to a certain point! The recommended maximum daily intake is 2g per Kg of bodyweight per day and there is no proven benefit to you exceeding this amount as the excess protein will not be converted to muscle.
For example: Consider a semi-pro female footballer who weighs 58kg. She trains three times a week and weight trains once a week. From the table below she would fall into the ‘Team Sports/Power Sports category and her daily protein requirements would be 1.4-1.7g per Kg of bodyweight (BW).
Therefore, her daily protein requirements are between 81.2g and 98.6g per kg BW.
(58x1.4 = 81.2g: 58x1.7 = 98.6g).
Proteins which contain all the essential amino acids in a proportion similar to what you require are said to have a high biological value (HBV) and are found mainly in animal sources. Proteins missing one or more essential amino acids are said to have a low biological value (LBV), and these are commonly found in plants, nuts and seeds. You can still meet all your protein needs from LBV foods however by combining different sources, such as peanut butter on whole grain bread.
"When planning your sports nutrition diet, you should always place the greatest emphasis on hitting your carbohydrate and protein targets, but should also aim for a fat intake of between 20-35%"
Fats provide a rich source of energy; in fact, fatty acids provide more energy per molecule than carbohydrates. Unfortunately, during high intensity exercise your body cannot burn fat fast enough to provide all your energy needs which is why carbohydrates remain your number one energy provider.
Excess fat from your diet is stored in your adipose (fatty) tissue and also inside your muscles. Even a lean elite athlete will have approximately 70,000 kcal of stored fat in their adipose tissue and a further 1,500 kcal stored in muscle tissue.
You use fats as an energy source only in light to moderate intensity exercise and during rest periods between bouts of high intensity exercise such as high intensity interval training (HIIT). An endurance athlete for example will get up to 75% of their energy from fat alone.
When planning your sports nutrition diet, you should always place the greatest emphasis on hitting your carbohydrate and protein targets, but should also aim for a fat intake of between 20-35%. For good health, your fat intake should never fall below 15% of your total calorie intake.
For example: If your total daily calorie intake is 2250 kcal, remembering that each gram of fat contains 9 kcal, you should aim for a daily fat intake of between 50g and 87.5g.
(20% = 2250 x 20/100 = 450kcal 450/9 = 50g) (35% = 2250 x 35/100 = 787.5kcal 787.5/9 = 87.5g)
Well, that brings us to the end of the first of three Sports Nutrition Blogs. I really hope you have enjoyed reading this one and have taken at least a little bit of something from it. The next one, which I promise will not be as long, will look into nutrition timing; what and when you should eat immediately before, during, and after exercise.