Sports Nutrition

To help ease confusion from the many messages to do with athlete nutrition, the experts at the Australian Institute of Sport have prepared a series of fact sheets.

The documents represent the latest scientific information about the use of and possible benefit of nutritional supplements including caffeine, creatine, protein, antioxidants and sports drinks, bars and gels.

To find them, login to CrackerSports , then simply search for ‘AIS fact sheets’.

They are essential reading for serious athletes and coaches.

These foods are champions when it comes to helping athletes sustain quality training:

1. Avocado – tasty alternative to butter or margarine as a sandwich spread or a snack on its own. Avocado contains 17 vitamins and minerals including vitamins A, C, E and all B vitamins except B12. In potassium, it’s second among plant foods only to Bananas!

2. Nuts – Great source of protein, fibre and healthy fats. Pecans & Walnuts are high in Omega-3 fats. Brazil nuts are high in selenium which may help protect against cancer, depression and Alzheimer’s.

3. Bananas – High in potassium and carbohydrates – the preferred fuel for muscles, blood and brain before and after exercise.

4. Salmon – High in protein and Omega-3 fats. Herring, Sardines and Mackerel also offer quality fish oils. Omega 3s may also have anti-inflammatory effects.

5. Chicken (skin off) – Excellent source of protein for growth and repair and development of the muscles. Red meat and eggs are also a great source of protein for those building muscles.

6. Creamed Rice – Excellent and tasty source of carbohydrates for quality training and a top desert.

7. Skim milk powder – Cheap source of whey protein – mix with milk and banana or other flavourings.

8. Garlic – Might just help you reduce the chance of catching a cold.

9. Ginger – Its antioxidants support immunity and ginger is also great for digestion and has an anti-inflammatory affect, to assist recovery.

A research review just published in the highly regarded journal Sports Medicine discusses the optimal way to put energy back into the body after moderate to high intensity endurance exercise.

In summarizing the results of a large number of studies the authors concluded that "carbohydrate should be ingested as early as possible in the post-exercise period and at frequent (i.e. 15- to 30-minute) intervals throughout recovery to maximize the rate of muscle glycogen resynthesis."

Aim to eat more sugary foods in that initial recovery period: "Solid and liquid carbohydrate supplements or whole foods can achieve this aim with equal effect but should be of high glycaemic index and ingested… at a rate of at least 1 g/kg/h in order to rapidly and sufficiently increase both blood glucose and insulin concentrations throughout recovery."

The reviewers also said that adding ≥0.3 g per kg of body weight per hour of protein to a carbohydrate supplement results in a synergistic increase in insulin secretion. This can have the neat effect of accelerating muscle glycogen resynthesis.

Specifically, if for some reason you can’t get enough carbohydrate to replenish your stores, then adding protein may at least partially compensate for the limited availability of ingested carbohydrate.

Source: Sports Medicine, Volume 40, Number 11, 1 November 2010 , pp. 941-959(19)

Some interesting research encouraging drinking during your workout has been published recently in the Perceptual and Motor Skills Journal.

Conducted by Biological Psychologist Kirsten D’Anci at the prestigious Human Nutrition Research Centre at Tufts University, the study found that athletes who consumed zero fluid during an exercise session reported higher levels of both anger and depression on a mood scale after the session.

After a training session they found that very slight dehydration of only 1-2 % of body weight (a 0.75 litre loss of fluid in a 75 kg adult) was enough to cause what the researches called a “a global negative mood” . The symptoms included signs of confusion, fatigue and decreased vigour (energy). These factors were 33% higher than the group that exercised and drank fluid through the session.

The cause? The researchers proposed that the dehydrated group actually experienced a very slight shrinkage of the brain cells. (Picture a plump green grape versus a dried sultana). This shrinkage causes a chemical imbalance to occur and this can increase irritability and potentially trigger headaches.

The solution: aim to consume 250 mls (a glass) of water or sports drink every 30 minutes of exercise and feel happier!

Just as important as what you eat is when you eat - the timing of the intake of key nutrients helps to convert your hard effort in the gym or on the field into a fitter and stronger you.

For instance, a protein-rich mini-meal before a strength training session will provide the building blocks for protein synthesis, while carbohydrate consumed at this time can provide fuel for the session.

After training, the intake of protein and carbohydrates will enhance the recovery processes of refueling, repair and adaptation. However, you do need to train yourself into effectively timing your nutrient intake and plan ahead for when good food is hard to find.

Why is Timing Food Intake so Important?

Resistance exercise leads to overall muscle tissue breakdown. Just after a strength session, the body is actively seeking protein to re-build muscles. A pre-exercise protein snack will mean that protein will already be digested and available to the body’s cells at the end of the session. Post-exercise, consume some more protein, plus carbohydrates to continue the repair and rebuild process.

Endurance training depletes the body’s stores of glycogen (stored carbohydrate). In the first 30 min after exercise the body is starving for carbohydrates and is biochemically more active in storing available carbohydrate. During this post-exercise window, it’s important to give the body the carbohydrates it craves.

Pre-Exercise Nutrition

Allow 1-2 hours between finishing a meal and a beginning a training session. Personally, I like a 2 hour window, but you can get away with shorter periods if the food is more easily digestible (eg, a low-fat & liquid). The aim is to have the stomach empty of food when you start training or competing. Having food in the stomach draws in blood to aid digestion. During exercise that means less blood for the muscles and lower potential performance.

Some athletes may be wary of eating carbohydrates in the hour before exercise for fear of this leading to a rapid drop in blood sugar at the start of exercise, which could impair performance. While this was once a prevalent theory, more recent research and reviews have shown no negatives for performance. However, every athlete should experiment with the timing of carbohydrate intake pre-exercise to determine how it affects them.

Choose a quick and easy snack before early morning workouts. A liquid meal supplement, such as PowerBar ProteinPlus Powder Drink, is a convenient and readily digested source of protein and carbohydrate. Where there is no time, or you are unable to tolerate a meal or snack before a hard morning session, fuel the workout by drinking a sports drink during the session.

Post-Exercise Nutrition

The body starts to replace its depleted energy stores and repair microscopic damage to muscle fiber straight away after exercise. Therefore, provision of depleted nutrients post-exercise will accelerate recovery.

Scientists studying the role of carbohydrate in exercise say that eating carbohydrates starting from 15 to 30 minutes after exercise, followed by additional carbohydrate feedings, will optimize muscle glycogen replacement.

A delay of a few hours in the ingestion of carbohydrates post-exercise will slow the rate at which the body stores glycogen. For the casual athlete, pack some fruit, fruit juice, or a fluid replacement beverage for a post-workout snack. Then, consume a mixed high carbohydrate and protein meal (such as rice with grilled chicken and vegetables) shortly thereafter.

For the heavily training endurance athlete, consume a post-exercise meal with a good source of protein and 100 grams of carbohydrate, followed by an additional carbohydrate feeding about two hours later.

I’d always have a packet of lollies/candies in the glove box of my car to eat on the way home after training. The high Glyemic Index of these sugary sweets gets the energy in fast.

Effective eating after a strength training session has slightly different needs - kick-start the recovery processes by consuming 10–20g of protein and 1gm of carbohydrate per kilogram body mass. If it is not convenient to have a meal soon after the session, start with a snack that can provide these nutrients, and resume normal meal patterns later.

After a gym session, I’d buy a little packet of beef jerky and a flavoured milk drink and consume them on the way home. The jerky is very high in protein while the milk provides fluid, carbohydrates and protein.

For more on this topic you might be interested in the book Nutrient Timing: The Future of Sports Nutrition . I haven’t read it yet, but am keen to as it rates 4.5 stars on Amazon.

Here are some notes from a great Louise Bourke talk at the AIS last week. Louise is one of Australia’s leading sports nutritionists - she’s no dummy!… but these are key points for the athlete’s nutrition.

Strategies to Loose Weight and Body Fat

There is no single successful strategy - the plan must be tailored to the individuals’ needs and goals.

Biggest problems with loosing weight:

• Too much food/large serving sizes
• Too much fat
• Too much energy - dense, low ’satiety’ food
• Poor eating behaviors
• Overdoing sports needs [eg, assuming you need to eat a lot protein bars]

What can you do for weight loss?

• Have the right sized proportions for you
• Make meals more filling or slow to eat - salads, fiber, lower GI foods, very hot & spicy foods.
• Reduce fat intake
• Avoid easy to consume foods kike drinks and sugary foods
• Know your real food requirements for training, taper and competing

Sports Nutrition and Protein

• Gaining protein (and therefore muscle) in the body is all about accumulating situations of increasing protein synthesis vs breakdown over the day [ie, training, then eating the right stuff].
• It’s all in the timing - there’s a good response when you consume protein in the hour after resistance (and endurance) training.
• Maximal response occurs with about 20g high quality protein ingested just after training. 10g is ok for those looking to loose weight.
• Optimal weight gain requires high energy intake (incl. protein).

If you eat too much protein:

• Expensive!
• Kidneys will suffer
• Bones will suffer
• You will increase your ability to breakdown protein for fuel [and you don't want to breakdown your muscles].

Hydration for Athletes

• Things that help you drink - good taste, a little salt in the drink (which helps keep fluid in the body) and a good plan to replace what you’ve sweated out.
• Urine output is important too - the body needs to urinate during the day as a regular part of good health.
• Caffeine has been overrated as a substance that induces dehydration.

Why Drink a Sports Drink?

• They encourage you to drink more because they are a little salty and taste better than water.
• They fuel your muscles and brain.

When to Drink a Sports Drink?

• For quality workouts - high-intensity sessions, especially long sessions.
• When you need to increase your energy intake to gain weight - it also helps stop protein breakdown during long sessions.
• When you are in a high volume phase of training - it may protect your immune system.
• Look after your teeth by brushing well and rinsing your mouth with water.

Recovery Nutrition

• Refueling, rehydration and protein synthesis can’t occur without nutrition - fluid, carbos, protein.
• Effective recovery only occurs after eating the right things.
• Some athletes over-focus on expensive sports foods and supplements, but everyday foods are cheaper and often better.
• Schedule a meal just after a session where possible.
• Include a ‘rainbow’ of colors of fruits and vegetables every day.

Supplements for Athletes

• Advertising messages are often confusing.
• Adequate attention must be paid to all the ‘big ticket’ items that must can maximize performance - there are no short cuts. ‘Old fashioned’ things like a balanced diet, training and recovery strategies remain as important as ever.
• Supplements can be contaminated with substances that could produce a positive drug test - check them with your authority.
• Probably beneficial supplements include caffeine, iron supplements, carbohydrates, proteins - a study showed that relatively low levels of caffeine (700mls of coke) enhanced endurance cycling performance. Louise suggested starting an event without caffeine in the system, taking it toward the middle of the event when it might be needed most. Try caffeine strategies in training as it may affect recovery and sleep. People respond differently to this drug.
• Little benefit from carnitine, chromium picolinate, ginseng, co-enzyme Q10.

Every few Olympics comes one with hot and humid weather - Athens was hot and dry, Sydney mild, but Atlanta (1996) and Beijing (2008) had the double whammy of heat and humidity.

Physiology 102 taught us that the body secretes sweat when it’s too hot. Physics 101 told us that there is a cooling effect when water (sweat) evaporates.

However, when the air is also saturated with water vapor, sweat won’t evaporate so well and will probably fall to the ground before it has a chance to cool the skin. Since the body doesn’t get any cooler, the body continues sweating.

Obviously the hotter and more humid the weather, the more sweaty you get and hence the potential for dehydration.

These conditions motivate the sport science boffins to revisit the demands on athletes to stay cool and hydrated in conditions that make you really sweat.

Why is it so Important to Stay Hydrated When Playing Sport?

The loss of water and electrolytes from the body has a few negatives but most notable is the decrease in blood volume and resultant reduction in oxygen transport resources. Just 1-3% dehydration has been shown to have a negative impact on exercise performance.

This is a major challenge especially in sports where it’s hard to drink a lot because you’re working hard or you don’t have a free hand, such as in team sports, sailing, distance running, road cycling, etc. To overcome this the athletes need to have a strategy in place to stay hydrated during the event, especially if the competition extends over multiple days

How much/when: drink 125mls every 15 mins (500ml/hr)… or more if able.

What: A cool 6% Carbohydrate Solution with Sodium & Potassium.

The major sports drink brands have products that are ideal for athletes to drink during competition.

Also, sip some cool (16 deg C/ 60 deg F) sports drink during your warm-up. Cooler fluids are absorbed quicker and cool the body.

Athletes in multi-day events needs to be on the lookout for signs of dehydration:

• Changes in body weight – 1kg lost in a day equals a liter of fluid lost
• Changes in quantity and color of urine - reduced output and darker stream generally indicates fluid loss
• Increased lethargy or elevated resting heart rates
• Headaches
• Difficulty in concentrating
• Increased perception of exertion

Getting Ready for Exercise in Heat & Humidity

Louise Bell, Sports Dietitian at the New South Wales Institute of Sport and to the Australian Sailing Team, has the following tips for staying hydrated in humid conditions:

• Allow the body time to acclimatise to the humid conditions – either train in a hot, humid environment; and/or arrive 7-10+ days prior to competing in these condition.
• Understand your body’s own sweat response and practice drinking strategies in a training situation. Develop a plan for yourself.
• Begin competition well-hydrated and start drinking early – small amounts of fluid more often are likely to better maintain your hydration status than going long periods with little or no fluid.
• Water may not be enough – sports drinks are a better choice in hot, humid conditions as the electrolytes assist fluid uptake and retention by the body.
• Include some salty foods as part of your recovery meal or snack (eg, Vegemite sandwich, low fat cheese, small packet of savory crackers or chips). Salt is the primary electrolyte lost in sweat and adequate intake (plus fluid!) will enhance the rehydration process in hot conditions. But you don’t need to go overboard, as most of us consume enough salt naturally in our diet without having to add salt to a meal.

Further reading: Analysis of the Beijing Olympic marathon - how small athletes gain in the heat.

I’m not sure if I actually have heard people ask this possibly absurd question, but I get the sense that people do all the time. Let me explain.

Many diet advertisements focus on what you eat - and whether it is yummy and filling. They’re both important things, but education as to the content of foods, their nutritional value and the role they play in a healthy diet are more important criteria to help people eat well for a lifetime and for athletes to perform their best.

There’s the simple Chinese Proverb: “Give a man a fish and he will eat for a day. Teach him how to fish and he will eat for a lifetime.”

Athletes need high performance bodies and to have one it’s best that you learn and know how the fuel you’re eating will affect your performance. You need to have an idea of how every bite and every mouthful will affect your hydration, the glycogen stores in your muscles and liver, your electrolyte balance and your levels of vitamins and micro nutrients .

No, I don’t expect you’ll have access to blood and biopsy results to give you this information. But you should learn about effective nutrition for athletes and to notice the signs of health in your body. You can use these indicators:

• Changes in your body weight, measured daily, will indicate your hydration status and also your general volume of food intake.
• Poo : Changes in the size will indicate how much food the body has absorbed. Very large stools may indicate overeating. Very soft stools may indicate a low fiber diet.
• The color and volume of your urine will indicate your hydration status.
• Heart rate in the morning will indicate your recovery from the previous day’s training - 5 bpm above average resting HR indicates fatigue; 10 bpm above means the body is struggling and you should probably have the day off (or you’re very dehydrated).
• You may be able to sense your immune status by sinus discomfort, a craggy throat or just general tiredness.

Principles of the athlete’s weight loss:

• Energy out needs to be more than energy in - but not by a lot, or training will suffer.
• Give yourself plenty of time to reduce your fat levels. Set a goal - say 2kg/4.4lbs over two months - that works out at just 33g/1.2oz a day. Weigh yourself each day and keep a graph.
• Increase fiber intake a little eg, change from white bread to wholemeal. Check the nutrition labels on packaged foods – anything above 8g dietary fiber per 100g of food is pretty good. The fiber will pad out your meals but is not digested.
• Make sure the timing of your meals is good - help your recovery from training with some high GI foods.
• If exercising in the morning try some diet coke (<200mls) 10-45 mins before starting – it can help get your metabolism going to break down the fats and provide a bit more stimulation when you might otherwise be feeling flat. For exercise sessions later in the day, begin them just when you start to feel hungry as this will also help delay the meal and burn fat.
• Generally aim to reduce the fat content of your meals – trim visible fat from meat and again check the nutrition labels where possible to find foods with fat less than 5g/100g.

If you’re a small female (<62kg/136lbs) who wants to loose weight and still train well you've got a formidable, but doable challenge. To ingest all of your daily nutrient requirements you have be quite careful with what you eat because the total volume of food you can eat is relatively low, so each meal should be thought out.

Since you will be limiting your food intake, quality is important and keeping up a regular course of multi-vitamin supplements will help you avoid missing out on any nutrients. You are likely to feel more tired at times than normal. Too bad! Your performance will improve, making light of the short-term discomfort.

If you like, you can view it in terms of personal sacrifice, but if you’re goals are firm and motivation high, then it’s just part of the job.

To learn a lot more:

Sports Nutrition Guide Book

Sports and Exercise Nutrition

Sports Nutrition for Endurance Athletes

Survival for the Fittest