Sports nutritionist Jacky Hems, answers your questions.
Sports nutrition has changed in recent years and the days of carbohydrate-loading for endurance sports and high-protein diets for strength/resistance exercise is being replaced with the recognition of the need for a more balanced approach in both types of exercise. Many of the principles of good health and optimum nutrition can be applied to sports nutrition. The key additional element is adjusting these to achieve maximum performance, regardless of the level you are at when it comes to fitness and exercise. You may find that some of these adjustments conflict with what you have come to understand about healthy eating, particularly around the consumption of carbohydrates and insulinInsulin is a hormone made by the pancreas. It is responsible for making the body’s cells absorb glucose (sugar) from the blood…. release. However, I will explain why these adjustments are important and help you to achieve the maximum benefits from your exercise programme. The requirements for sports nutrition will vary from person to person depending on the type, intensity and frequency of sport/exercise you do, your personal goals and biochemical individuality. So the following answers to our most frequently asked questions are based on general principles, with some examples to give you more guidance.
When and what to eat before and after exercise.
As well as knowing what and how much to eat, one of the most powerful differences you can make to your training regime is knowing ‘when’ to eat around your programme. Two of the leading authors on this subject are Ivy and Portman and in their book Nutrient Timing: the Future of Sports Nutrition (1) they describe three key nutrient timing phases – the Energy, Anabolic and Growth Phases. These are primarily focused on strength training but with a few adaptations can be applied to endurance training. Understanding the role of some key hormones released during and after exercise is important, as it alters what is best to eat, and when.
The Energy Phase – during a workout
This covers the period of a workout. During this ‘catabolic’ phase, when you are burning a high amount of energy, the main objective is to spare muscle glycogen (which is the muscle’s energy reserve) and proteinProteins are large molecules consisting of chains of amino acids. Proteins are essential nutrients for the human body – they are a building block of… to help reduce muscle fatigue and damage and enable faster recovery post-workout. If you’re exercising for an hour or more (e.g. intense strength training, marathon, triathlon, cycling), at around 10-20 minutes before you start have a drink/gel consisting of 30-60g high GI carbohydrateCarbohydrates are the primary source of energy for the body as they can be broken down into glucose (sugar) more readily than either protein or… (glucose, sucroseSucrose is commonly known as table sugar…. or maltodextrin – fructoseFructose is a simple sugar that occurs naturally in fruits, vegetables and their juices, as well as in honey…. can cause digestive problems for some people) and add around one third of that amount whey protein (see Benefits of Whey Protein below for alternatives) for strength training. During exercise, for both strength and endurance training, continue with a ratio of around 3:1 carbohydrate to protein per hour of exercise (if you’re exercising for less time than this you shouldn’t need to supplement), with added electrolyte rehydration salts, vitamins C and E and magnesiumWhat it does: Strengthens bones and teeth, promotes healthy muscles by helping them to relax, also important for PMS, important for heart muscles and nervous…. The amounts needed vary from person to person depending on the duration of your workout and your caloric needs. The following amounts are recommended by Ivy and Portman (1) High GI carbohydrate 20-26g Whey protein 5-6g Leucine 1g Vitamin CWhat it does: Strengthens immune system – fights infections. Makes collagen, keeping bones, skin and joints firm and strong. Antioxidant, detoxifying pollutants and protecting against… 30-120mg Vitamin EWhat it does: Acts as an antioxidant, protecting cells from damage, including against cancer. Helps body use oxygen, preventing blood clots, thrombosis, atherosclerosis. Improves wound… 20-60IU Sodium 100-250IU PotassiumWhat it does: Enables nutrients to move in and waste products to move out of cells, promotes healthy nerves and muscles, maintains fluid balance in… 60-120mg Magnesium 60-120mg with these quantities doubled for athletes over 75kg (Table 1: Ivy and Portman, Recommended Supplements for the Nutrient Timing System Energy Phase) On a practical level, unless you have time to make up your own formula, try a pre-made product available from specialist sports shops, health food shops and online. Obviously ratios and ingredients in bought formulas will vary and you may need to experiment to find a product that suits you. Not all contain vitamins and magnesium so you may want to add these. Some formulas contain creatine, which is crucial for powering muscle contraction. Look for natural products and avoid those that include artificial colours, flavours and sweeteners. Some ranges include soya, pea and hemp protein powders, as alternatives to whey. Having a combination of carbohydrate and protein during a workout has been, and still is, hotly debated, particularly for endurance athletes. However, in a study of a small group of cyclists given a placebo, carbohydrate-only or carbohydrate-protein combination drink every 20 minutes during various exercises to exhaustion, those given the carbohydrate-protein combination achieved the highest level of aerobic endurance performance. In another small study looking at the effects of carbohydrate with and without protein during resistance exercise, the combination of carbohydrate and protein together lowered the rate of muscle protein breakdown compared to carbohydrate on its own, so I would recommend having a combination of both during exercise.
If you’re just starting out and haven’t tried drinks or gels before, an alternative is to eat a banana and a few nuts (around 30g) about an hour before you exercise. A note on the consumption of high GI carbohydrates and in liquid form – while in other aspects of nutrition I would not usually recommend this type of carbohydrate and would err on the side of caution with using liquid foods on a regular basis, sports nutrition is different. Simple carbohydratesSimple carbohydrates are also referred to as refined carbohydrates. The process of refining turns a complex carbohydrate into a simple carbohydrate. Simple carbohydrates cause a… are needed for faster absorption and delivery to the muscles and use less energy to do this than eating whole foods Moving on to hormones, here’s why they are important. Glucose is an essential energy source during this phase and the hormones glucagon and cortisolCortisol has been nicknamed ‘the stress hormone’ as it is released in higher levels during the body’s flight or fight response to stress. Levels of… are responsible for increasing blood glucose through the breakdown of fatThere are many different types of fats; polyunsaturated, monounsaturated, hydrogenated, saturated and trans fat. The body requires good fats (polyunsaturated and monounsaturated) in order to…, carbohydrate and protein. Amino acidsAmino acids are commonly known as the building blocks of protein. There are 20 standard amino acids from which almost all proteins are made. Nine… are also used up (particularly glutamine, and the branch-chained amino acids (BCAAs) leucine, isoleucine and valine). The more intense a workout the more cortisol is released, causing greater protein breakdown. Insulin has a reverse action to these two hormones and increases the removal of glucose from the bloodstream, either using it at the time or storing it for later use. And this is where insulin can have a positive effect! By having the right amount of carbohydrate during exercise, the elevation of insulin can lessen the effects of cortisol, leading to a lower rate of protein breakdown. Post-exercise it can be even more effective, as you’ll see in The Anabolic Phase. The impact of insulin on lowering cortisol may also have a positive effect on maintaining immune function. High levels of cortisol released during high-intensity/prolonged exercise can suppress the immune system, leading to a greater risk of infection. That is why I recommend having some high GI carbohydrate before and during extensive exercise.
The Anabolic Phase – recovery and muscle repair
This phase is the most crucial because it is when the body will change from breaking muscle down to starting the repair and build process, necessary for muscle building and recovery as well as glycogen replacement, provided the right nutritional conditions are in place. There is about a 45-minute window after exercise when this needs to happen. During this time, the muscles are particularly sensitive to insulin, and consuming a carbohydrate/protein combination results in a higher insulin response than just carbohydrate alone. Once insulin levels are high, the anabolic reactions necessary for repair and recovery start to take place, to enable muscle growth. Insulin also increases blood flow in the skeletal muscles, helping to speed up elimination of metabolic wastes. If the right nutrients aren’t consumed during this window, the muscles can continue to break down so are not repaired as quickly or effectively, resulting in a negative net protein balance. Compensating after this time does not have the same effect. Post-workout to shift your body into the repair and build stage, an amount of 1g of carbohydrate/kg body weight and around 10-20g protein is recommended as a general guideline (2). Ivy and Portman (1) recommend these amounts: High GI carbohydrate 40-50g Whey protein 13-15g Leucine 1-2g Glutamine 1-2g Vitamin C 60-120mg Vitamin E 80-400 IU Potassium 60-120mg with these quantities doubled for athletes over 75kg (Table 2: Ivy and Portman, Recommended Supplements for the Nutrient Timing System Anabolic Phase)
Most pre-made recovery formulas offer a ratio of 3-4:1 carbohydrate to protein. Or try making your own by blending together around 20g protein powder, 100ml fruit juice, 1 banana, 50-75g berries (fresh or frozen), 1 small pot of plain yoghurt (dairy or soya), 1-2g leucine and 1-2g glutamine (2). Again, the best way to take in the nutrients needed in this Phase is in liquid form for the same reasons as The Energy Phase.
The Growth Phase – building muscle
In the 20-24 hour period after exercise, the majority of muscle mass increase takes place. Maintaining an anabolic state for as long as possible (around 4 hours) can help this, and also means insulin sensitivity will be maintained for longer. Beyond that, muscle will continue to grow but at a slower rate. Switching back to whole foods is important here and you should aim to eat a meal 2-4 hours after exercising of around 2:1 carbohydrate (which includes non-starchy/green leafy vegetables as well as low glycaemic load (GL)Glycaemic load is a unit of measurement that tells you exactly what a particular food will do to your blood sugar. Foods with a high… carbohydrates, see below) to protein foods. Lower carbohydrate consumption is effective at this stage, especially if you want to burn fat – eating excess carbohydrates can lead to fat storage which most athletes will want to avoid. Achieving a positive nitrogen balance (i.e. your body eliminates less protein than you consume) can help to continue the increase in lean muscle mass, hence the need for protein. In practical terms this would mean a third of what’s on your plate is protein, one third vegetables, one third starchy but low GL carbohydrates (e.g. wholegrain pasta or brown rice, not white). In this phase, an optimal diet is primarily based on whole foods for all meals and snacks to include lean sources of animal protein (lean meat and fish, eggs and low-fat dairy foods if tolerated), low GL carbohydrates and grains (such as brown rice, wholemeal pasta, sweet potato, butternut squash, quinoa) and a wide variety of fresh vegetables, essential fats from oily fish, nuts, seeds and oils such as virgin-pressed olive and coconut oils, plus sufficient amounts of water and water-based drinks, for example, herbal teas. Fruit should ideally be kept to around two-three portions a day, and processed and refined foods should be avoided. There are no specific foods that are more or less beneficial for specific types of exercise – the key is to stick to the guidance above. Water is just as important as any nutrient and adequate hydration is necessary during all Phases. This will be covered in the Hydration section.
Benefits of whey protein
The best and easiest way to integrate whey protein into your diet is through pre- and post-workout drinks/shakes. Whey protein is a complete protein so it contains all the essential amino acids (EAAs) (including high levels of the BCAAs), which the body can only obtain from food – all nine EAAs are needed to repair and build muscle. Leucine in particular activates the anabolic phase and native whey protein (so-called because of the production process it goes through which means it is produced from milk rather than cheese, as with standard whey protein) contains the highest levels of leucine compared to other types of whey protein. Look for native whey protein products for your own post-exercise drinks or consider supplementing leucine if using standard whey protein. Whey protein is easily digestible and rapidly absorbed so the switch from muscle breakdown to muscle recovery starts to happen more quickly. Different whey protein products contain varying levels of lactose so are unlikely to be suitable for those who are intolerant. Versions that are 99% lactose-free are now available and for those who are completely intolerant or allergic or vegan, the best alternatives include soy protein powders, which also contain all the EAAs (although in lower quantities than whey), pea, hemp and brown rice proteins. There is some evidence that suggests a link between dairy products, milk in particular, and risk of cancer. However, other studies have not found that link. If you are concerned about this due to regular consumption of whey protein, I would suggest that the rest of your diet is low in other dairy products or rotate protein powders to include the alternatives mentioned above.
Determining your own nutrition requirements
To help determine what to eat each day you need to know your daily/weekly calorieCalories are a measure of the amount of energy in food. Knowing how many calories are in the food we eat allows us to balance… needs (calculated using your basal metabolic rate (BMR) plus your activity factor) and your daily/weekly exercise calorie needs and how much protein and carbohydrate in particular you need. This will help determine calories required from fat (good sources as above). My Fitness Pal is a good free online tool for calculating BMR, calorie requirements and calories burned from exercise. It also has a very large foods database, which gives detailed nutrition facts. As a guideline, the following amounts of protein and carbohydrate are recommended: Protein – for the sedentary person the current Recommended Dietary Allowance (RDA) is 0.8g/kg of body weight. For those exercising regularly this increases to: Endurance athletes – 1.2-1.4g/kg Strength athletes – 1.2-1.7g/kg Carbohydrate – this very much varies according to the intensity and duration of exercise and how many calories are obtained from protein. The approximate ranges are from around 3-5g/kg body weight/per day for moderate strength training to around 7-10g/kg body weight per day for intense endurance exercise of between 1-3 hours. Practical examples For strength training an approximate breakdown of calories would be in the region of 24% protein, 43% carbohydrate and 33% fat. For example:
• For a 60kg female training once a day, requiring 2,340 calories per day this translates to approximately 139g protein, 250g carbohydrate and 87g fat. A sample day to show how these break down could look like this:
Nutritional values taken from My Fitness Pal food database (www.myfitnesspal.com) and Exercise drinks from Ivy & Portman (1)
• For a 90kg male training once a day, requiring 3,800 calories per day this translates to approximately 226g protein, 411g carbohydrate and 138g fat. In this case, where a high number of calories are needed and particularly where high protein quantities are required, increase exercise drink amounts by around a third to double, depending on workout length and include a further Growth Phase workout drink in the evening. Increase carbohydrate and protein portion sizes by about a third at mealtimes and include a balanced snack of around 500 calories either in the morning or afternoon, depending on workout time, for example, bread/oat cakes/Ryvita with peanut butter plus fruit with yoghurt or milk. For endurance athletes the proportions would be adjusted to accommodate a greater number of calories from carbohydrate, for example:
• For a 60kg female, aged 35, cycling 80 miles per week (at 10 miles per hour), requiring 2200 calories per day, this translates to approximately 84g protein, 300g carbohydrate and 73g fat. A sample day to show how these break down could look like this:
Nutritional values taken from My Fitness Pal food database (www.myfitnesspal.com)
• For a 70kg male, aged 35, cycling 105 miles per week (at 15 miles per hour), requiring 2865 calories a day this translates to approximately 98g protein, 420g carbohydrate and 88g fat In this case, where carbohydrate in particular needs to be increased to meet daily calorie requirements, increase the carbohydrate in exercise drinks (in proportion with increasing protein), increase carbohydrate amounts at mealtimes by about a third and include either a morning or afternoon snack, depending on training time, for example fruit with oat cakes and nut butter/houmous/cottage cheese.
Hydration How much extra water do you need to drink if you have been exercising?
Hydration and how much you need to drink are very much about your individual needs, guided by your thirst. Here are some guidelines to help you work out your optimum hydration levels. There are many factors to take into account, for example, intensity and duration of exercise, the temperature you’re training at, your sweat rate and how hydrated you are when you start exercising. On a practical level, your optimal hydration weight can help to determine rehydration levels. After three to four rest days, weigh yourself first thing in the morning, having drunk a small amount of water (around 50-100ml) to satisfy thirst. Next, check your bodyweight before exercise when not rested and finally, check your weight after exercise on several workout days and take the average. (Your ideal training weight should be in the middle of your rested optimal hydration weight and your post-exercise average weight.) After a workout, aim to return to your optimal hydration weight as quickly as possible. Half a litre of water weighs approximately half a kilogram so you can work out how much water you need (3).
Urine colour can also indicate hydration levels – the ideal is a light, straw-like colour. If urine is a dark yellow you need to drink more water and a very light colour can indicate over-hydration. NB: Riboflavin (vitamin B2) alters the colour of urine to a bright green/yellow colour, and is contained in many multivitamin/mineral supplements. Also highly important when considering hydration is electrolyte (sodium, potassium, magnesium and calciumWhat it does: Promotes a healthy heart, clots blood, promotes healthy nerves, contracts muscles, improves skin, bone and dental health, relieves aching muscles and bones,…) balance. Electrolytes control energy production, storage and use so have a crucial role in exercise. Because we are all biochemically unique, specific amounts needed to re-balance your body will be a very individual requirement. If you include small amounts (see Table 1) during exercise, you can help to maintain your electrolyte balance. Drinking large quantities of water after exercise can cause sodium levels to drop so a drink containing electrolytes is preferable. Many pre-made formulas contain electrolytes or they can be bought separately and added to water. Coconut water is a natural source containing calcium, magnesium and potassium.
Foods to avoid because they are dehydrating
A high-protein diet, as favoured particularly by some strength athletes (though it is not as beneficial as may have been previously thought) can have a dehydrating effect. The excretion of protein requires a higher amount of water than for fats and carbohydrates, and the neutralisation of high blood acid levels requires the release of calcium from bone, which therefore puts an extra load on the kidneys. Protein quantities required for different levels of activity have already been highlighted as has the importance of hydration, so the best advice here is to stick to these guidelines and continue rehydrating as much as you need to. Caffeine can be dehydrating because of its diureticA diuretic is a substance that increases the amount of urine produced and therefore makes you urinate more frequently…. effect, although the water loss from it is not so great. Having said that, caffeinated drinks don’t form part of an optimum nutrition diet! So keep these to a minimum, with no more than 1-2 cups per day. Sweet fizzy drinks can be dehydrating due to their high sugar content and should be avoided altogether. Alcohol also dehydrates and for most competitive athletes will be restricted most of the time anyway; for anyone else alcohol should be kept to a minimum.
List of the most hydrating foods
We get around 20-25% of our daily water intake from food. The majority of this comes from fruit and vegetables which contain a higher percentage of water than any other type of food. As can be seen from this table those with the highest amount of water include cucumber (96%), iceberg lettuce (96%), celery (95%), radish (95%), courgette (95%), tomatoes (93%), strawberries (92%), watermelon (92%) and grapefruit (91%). As mentioned, due to possible digestive problems associated with fructose, it is more beneficial to include fruit either as part of whole foods several hours before or after exercise or liquidising in a post-exercise drink.
Supplements Best supplements for energy
A wide range of vitamins and minerals are involved in producing and maintaining energy, particularly the B vitamins and electrolytes. However, as many others also support the body during and after exercise (for example vitamins C, D and E and ironWhat it does: As a component of red blood cells, iron transports oxygen and carbon dioxide to and from cells. Also vital for energy production…. and zincWhat it does: Component of over 200 enzymes in the body, essential for growth, important for healing, controls hormones, aids ability to cope with stress…), you are more likely to benefit from a good quality high potency multivitamin/mineral rather than taking individual supplements, together with extra vitamin C.
Supplements to support recovery
If you follow the Anabolic Phase above, you will help yourself to a faster recovery and may not need to supplement further, especially if you take a good quality multivitamin/mineral too. These may also help to support immune health and usually have good levels of antioxidants so again, it may not be necessary to supplement any specific nutrients beyond these. However, there’s a case for increasing antioxidants the more aerobic and endurance exercise you do by adding an antioxidantAntioxidants are substances that protect cells within the body from damage caused by free radicals. They help to strengthen the body’s ability to fight infection… complex, ideally containing alpha-lipoic acid, coQ10, glutathione or NAC, as well as the regular vitamins A, C, E and seleniumWhat it does: Antioxidant properties help to protect against free radicals and carcinogens, reduces inflammation, stimulates immune system to fight infections, promotes a healthy heart,…. This should be balanced with getting antioxidants from your diet, as there is some suggestion that high levels of antioxidant supplements can interfere with training adaptations. There’s also evidence that Montmorency cherry juice concentrate with water reduces muscle fatigue and aids recovery after exercise. As we’ve seen, restoring electrolyte balance after exercise is important and one option is to try magnesium in the form of an oil spray which is massaged directly into the skin for fast absorption. The answers to our most frequently asked questions should have given you some guidance on what to focus on, do differently and avoid with your own nutrition to support your training programme. Nutritionists specialising in sports nutrition can work with you on a one-to-one basis to put an individual programme together. You can find a local nutritional therapist in the ‘advice’ section here. Jacky Hems is available for one-to-one consultations in and around the Teddington, TW11 area and also runs Patrick Holford’s zest4life nutrition and weightloss groups. She can be contacted at firstname.lastname@example.org. Also see www.thenutritionmission.co.uk for more information.
Books and Articles Reference List
Ivy J and Portman R (2004) Nutrient Timing: The Future of Sports Nutrition. Basic Health Publications Inc. Functional Sports Nutrition (January/February 2012 edition) Functional Recovery Drinks. Target Publishing Ltd. Haynes A (2010) Sports Nutrition Functional Medicine Perspective Lecture, Institute for Optimum Nutrition.
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