Nutrition for sport and exercise

 

Hi Pulse Nation,

Below is an excellent article by the British Nutrition Foundation about the importance of a healthy diet to get the most out of a exersize regime:

 

We should all aim to eat a healthy, varied diet based on the principles of the Eatwell Guide, which matches our energy needs. This advice still applies when taking part in regular physical activity, such as going to the gym, swimming, running, cycling or team sports.

Following healthy eating guidelines alone can support an active lifestyle. However when exercising, your body will use up more energy. Unless you are trying to lose weight you may find that you need to eat more food to give your body the extra energy it needs.

Eating well for physical activity and sport can have many benefits including:

  • Allowing you to perform well in your chosen sport or activity;
  • Reducing the risk of injury and illness;
  • Ensuring the best recovery after exercise or a training programme.

A healthy diet for sport and exercise should contain plenty of starchy foods, plenty of fruit and vegetables, some protein foods and some dairy foods. It is also important to stay hydrated.

In this section, we will cover:

 

Foods for fuel and exercise

Carbohydrates

The main role of carbohydrates is to provide energy.

When they are digested, carbohydrates are broken down into glucose to provide readily available energy for the body to use quickly and effectively. Carbohydrates are the most important form of fuel for exercise and sports activities. The body can store carbohydrates in the muscles and liver as glycogen, and use these stores as a source of fuel for the brain and muscles during physical activity. These glycogen stores are limited, so it is important to be fully fuelled at the start of any exercise.  By not having adequate carbohydrate in your diet for exercise, you may feel tired and lacking in energy and not be able to perform at your best. So, regular intake of carbohydrate-rich foods is important to keep stores topped up. The correct food choices can help ensure the body has enough energy for activity, as well as help aid recovery.

Starchy foods are an important source of carbohydrates in our diet. Wholegrain varieties also provide fibre, which is important for digestive health, and a range of vitamins and minerals including B vitamins, iron, calcium and folate.

Good sources of carbohydrates in the diet include:

  • Bread
  • Breakfast cereals and porridge oats
  • Pasta, noodles
  • Rice
  • Couscous
  • Potatoes (with skins) and other starchy vegetables (e.g. sweetcorn)
  • Beans and pulses

Starchy foods should make up around a third of the food we eat. Fruit and milk contain carbohydrates in the form of sugars and can help to provide the body with a quick source of energy. They also contain many additional vitamins and minerals that help to keep us healthy. Starchy foods, especially high fibre varieties provide a slower release of energy and take longer to digest, so it’s a good idea to include some in every meal.

Food and drinks that contain high amounts of free sugars, such as sweets, biscuits, cakes and sugars-sweetened soft drinks, should generally be limited as they can lead to excessive calorie intakes which may cause weight gain. Frequent high intake of free sugars can also increase the risk of tooth decay particularly in those with poor dental hygiene. 100% fruit juices also contain free sugars, so limiting intake to a small 150ml glass a day is recommended.

Competitive sports people and athletes may require more carbohydrates than an average gym user to match the intensity of their activity level.  Estimated carbohydrate needs are outlined and depend on the intensity and duration of the exercise sessions:

Duration of sport or exercise sessions Recommended intake (per kg body weight per day)*
3-5 hours per week 4-5g
5-7 hours per week 5-6g
1-2 hours per day 6-8g
2 + hours per day 8-10g

*These requirements are general and consideration of energy needs and type of exercise should be considered.

Try not to meet your requirements by packing your entire carbohydrate intake into one meal. Spread out your intake over breakfast, lunch, dinner and snacks that fit around planned exercise.

The table below shows the carbohydrate content of some common foods:

Food source Serving size Carbohydrate content (g) per serving size
Pasta (boiled) Medium (230g) 76
Couscous Average (150g) 56
Rice, wholegrain (boiled) Medium (180g) 53
Jacket potato with skin (baked) Large (220g) 50
Wholemeal bread 2 thick slices (88g) 37
Sweet potato, boiled 2 medium (130g) 27
Banana 1 large (120g) 24
Porridge, made with low fat milk Medium (160g) 19
Crumpet, toasted 1 crumpet (40g) 18
Oatcakes 2 oatcakes (26g) 16
Sweetcorn Average (80g) 11

 

Protein

Protein is also important for health and physical activity. The main role of protein in the body is for growth, repair and maintenance of body cells and tissues, such as muscle.

Different foods contain different amounts and different combinations of amino acids (the building blocks of proteins). Essential amino acids are those that the body cannot make itself and so are needed from the diet. The full range of essential amino acids needed by the body (high protein quality) is found in:

  • Animal sources – meat, fish, eggs, milk, cheese and yogurt.
  • Plant sources – soy, tofu, quinoa and mycoprotein e.g. Quorn™.

As some high protein foods can also be high in saturated fat, it is important to choose lower fat options, such as lean meats or lower fat versions of dairy foods.

Most vegans get enough protein from their diets, but it is important to consume a variety of plant proteins to ensure enough essential amino acids are included. More information on vegetarian and vegan diets is available here.

The protein requirements of a normal adult are 0.75g per kilogram of body weight per day. For strength and endurance athletes, protein requirements are increased to around 1.2-1.7g of protein per kilogram of bodyweight per day.  If you are participating in regular sport and exercise like swimming/running or go to the gym on a regular basis, then your protein requirements may be slightly higher than the general sedentary population, in order to promote muscle tissue growth and repair.  However, most people in the UK consume more than the recommended amount of protein, so increasing your protein intake is generally unnecessary.

Consuming a healthy, varied diet containing nutrient dense foods will ensure you get enough protein without the use of protein supplements or special high-protein eating strategies, even if your needs are a little higher!  But try and spread your protein intake throughout the day.

Do I need extra protein to build muscle?

It is a common myth that consuming lots of extra protein gives people bigger muscles. Quite often, people taking part in exercise focus on eating lots of protein, and consequently may not get enough carbohydrate, which is the most important source of energy for exercise. A modest 20g of high quality protein, equivalent to approximately half of a medium sized grilled chicken breast or a small can of tuna, has been shown to be enough for optimum muscle protein synthesis following any exercise or training session. Any more protein than this will not be used for muscle building and just used as energy!

As well as including protein as part of a healthy, balanced diet, the incorporation of some protein after exercise is important for building new muscle tissues and repairing the damaged ones. See the section putting nutrition into practice for ideas of how this can be done.

The table below shows the protein content of some common foods:

Food source Serving size Protein content (g) per serving size
Chicken breast grilled Medium (130g) 42
Salmon fillet grilled Large (170g) 42
Rump steak grilled 115g (5oz) 36
Tuna canned in brine Small can (100g) 25
Baked beans 1 can (415g) 22
Almonds 100g 21
Haddock grilled Medium (85g) 20
Eggs 2 average size eggs (100g) 13
Lentil soup 1 can (400g) 12
Half fat cheddar cheese 4 tbsp grated (40g) 11
Low fat milk 300ml 10
Greek style plain yogurt Small pot (120g) 7
Low fat fruit yogurt Small pot (120g) 7

 

 

Fat

Fat is an essential nutrient for the body, but it is also a rich source of energy. Consuming too much fat can lead to excess energy intake which can lead to weight gain over time. It is important to follow current healthy eating guidelines, ensuring fat intakes are no more than 35% of total energy intake from food, with saturated fat intakes not exceeding 11% of total energy intake from food. Fats in foods typically contain a mixture of saturated and unsaturated fatty acids, but choosing foods which contain higher amounts of unsaturated fat, and less saturated fat, is preferable. Most of us eat too much saturated fat so to cut back on intakes, limit foods such as:

  • Pastries, cakes, puddings
  • Chocolate and biscuits
  • Some savoury snacks
  • Cream, coconut cream and ice-cream
  • Hard cheeses including cheddar
  • Butter, lard, ghee, suet, palm oil and coconut oil
  • Processed meats like sausages, ham, burgers and fatty cuts of meat
  • Fried foods including fried chips

Choose low fat options and foods containing unsaturated fat where possible. Replacing saturated fat with some monounsaturated and polyunsaturated fat helps to maintain healthy cholesterol levels. Good sources of these fats include vegetable oils such as olive, rapeseed and sunflower oils, avocados, nuts and seeds. Polyunsaturated fats provide us with essential fatty acids like omega 3 which are found in sunflower, flaxseed and linseed oil and walnuts, but it is the long chain omega 3 fatty acids which are associated with heart health and these are found in oily fish (e.g. mackerel, salmon and sardines). Click here to see more on fats.

Tips for making simple swaps to cut down on saturated fat:

Foods containing a high proportion of saturated fatty acids Swap for…
Butter, lard, ghee

 

Palm oil and coconut oil

Smaller amounts of oil containing unsaturated fats:

  • Rapeseed, olive, sunflower oil and spreads

Tips:

  • When using oils, try to measure out in a teaspoon or use a spray version to control your use
Processed and fatty cuts of meat
  • Lean meats

Tips:

  • Cut any visible fat off.
  • Choose skinless chicken or turkey (or remove the skin).
Whole milk, condensed milk or full-fat creams
  • Semi-skimmed, skimmed or 1% fat milk
  • Low fat creams
Cheeses that are high in fat, (e.g. cheddar)
  • Cottage cheese, ricotta and extra-light soft cheese

Tips:

  • Try to have smaller portions of cheese
  • Grate cheese to use in salads, sandwiches and fillings, so that less is used
Salad dressings
  • Making your own from scratch – try mixing lemon juice/vinegar, herbs and spices, with a small amount of olive oil or even low fat natural yogurt
Other tips to help cut down on saturated fat…

 

Cooking – frying, deep frying, roasting Try boiling, poaching, steaming, baking or grilling and add a minimal amount of fat.
Shopping Take time when food shopping and read food labels carefully to help you choose foods that are lower in saturates.

 

 

How to stay well hydrated

Sufficient fluid intake is essential for exercise and optimum recovery. Exercising causes the body to get warmer, so the body tries to cool down by sweating. This causes the loss of water and salts through the skin.

The amount an individual sweats varies from person to person and depends on:

  • Intensity and duration – longer and higher intensity exercise can cause greater sweat loss.
  • Environmental temperature – in hot, humid conditions sweat loss can increase.
  • Clothing – the more clothing that is worn, the quicker you are likely to heat up which may cause greater sweat loss.
  • Genetics – some people are just more likely to sweat than others.

Generally, the more a person sweats, the more they will need to drink.

Small water losses are not harmful. However, dehydration (water loss in excess of 2-3% body mass) can cause tiredness and hinder performance by reducing strength and aerobic capacity (especially in longer duration exercise), as well as having a negative effect on any further exercise sessions.  So, try and stay hydrated before, during and after exercise to prevent dehydration – water is generally best, but in cases of high-intensity exercise and excessive sweating, an isotonic drink may be better (see later section that covers other drinks).

For more information on healthy hydration click here

 

Putting nutrition into practice

The timing of eating and exercising can be important for how you feel and perform during your chosen activity. The body needs the correct fuel in the tank to perform well, however you want to avoid feeling too full or too empty during exercise.

Individuals vary in their preferred timing of food intake and amount that can be eaten before exercise. Some may find two hours is plenty of time to digest their meal, whereas others may feel uncomfortable when taking part in activity and need a bit longer. Experimenting with what, how much and when will help decide what suits you best!

Before:

  • Ideally, your pre-exercise meal should be low in fat and contain a portion of starchy foods, such as porridge, pasta or potatoes, and should be around 2-3 hours before exercising. For exampleif you have an exercise class at 5pm, have your pre-exercise meal at around 2pm.
  • However, if you leave eating before exercise any longer or don’t eat anything at all, you may lack energy and risk feeling light headed during exercise.
  • You could eat a small snack between your pre-exercise meal and exercise to top up energy levels. If you do, it is best to wait 30-60 minutes before taking part in any vigorous sports or exercise.
  • Making sure you are well hydrated before you start an exercise session is important, so try to drink regularly throughout the day and with your pre-exercise meal.

 

 

During:

  • Consuming some carbohydrates during exercise can enhance performance but this generally only applies to individuals participating in endurance or high intensity sports that last over 60 minutes, as this is when carbohydrate stores may substantially decrease (e.g. marathon/long distance running, football games or competitive swimming events).
  • It is important to consume plenty of fluids during exercise, especially if you are sweating heavily (also to replace electrolytes lost from sweating) and/or the environmental temperature is high.
  • Try to sip small amounts of fluids whenever possible during exercise to stay hydrated. Don’t wait until you feel thirsty, as this is a sign that you are already partly dehydrated. Keep sipping water before and during the activity, if possible, to keep hydration levels topped up.

 

After:

Food and fluid intake is also important for optimum recovery after exercise.

  • After a long run or exercise class, your carbohydrate stores will be lower, so it is important to replenish them, especially if you are doing more exercise later on that day or the following day.
  • The post-exercise meal should be based on starchy foods (preferably wholegrain) and include some high quality, lean protein. Consuming this as soon as possible after exercise will be most beneficial for recovery, restoring glycogen levels and muscle protein.
  • If you are unable to have a meal soon after exercise, try to have a small snack that contains carbohydrate and protein, such as a banana and a glass of low fat milk, within the first 30-60 minutes following exercise to begin the recovery process, especially if you have exercise within the next eight hours.
  • Don’t forget your meals should always be balanced so make sure you include fruit and vegetables to provide other important nutrients.
  • To replace the fluid lost from sweating, it is vital to restore hydration levels as part of recovery, so remember to drink plenty of fluids after exercising. See common sports nutrition questions section for the benefit of other drinks, such as milk, for recovery.

 

 

Tips to plan your meals and snacks:
  • Preparation – your pre-exercise meal, whether it is breakfast or lunch, should be around 2-3 hours before and include a good amount of starchy foods to ensure you have enough fuel in the tank. A small snack 30-60 minutes before exercise can help to top up energy levels.
  • Recovery – base your post-exercise meal on starchy foods and include some high quality, lean protein to help restore glycogen levels and muscle protein.
  • Both meals should also include some fruit and vegetables.
  • Good snacks for immediately after exercise should contain some protein, such as unsalted nuts or a glass of milk.
  • Try to opt for wholegrain carbohydrates and high quality protein foods, as well as nutrient-rich snacks.

 

Ideas for meals and snacks

Below are some examples of suitable meals and snacks for an individual who exercises.

Breakfast

 

Lunch Dinner Snacks
Porridge with low fat milk and fruit Baked potato (skin on) with tuna, and salad (use low fat mayonnaise) Wholemeal pasta with grilled chicken and vegetables in a tomato based sauce Fruit

Vegetables sticks with houmous

Low fat fruit yogurt

Malt loaf

Reduced salt/sugar baked beans on wholemeal toast

Guacamole, ½ wholemeal pitta

Rye crispbread with low fat cheese and grapes

Unsalted nuts or seeds

Low fat milk

Fruit smoothie (made with low fat milk and banana)

Oatcakes with peanut butter

Muesli (no added sugar) or wholegrain cereal, with low fat milk and fresh or dried fruit Eggs (boiled, poached, scrambled, omelette) on wholemeal toast with vegetables Chilli con carne – lean mince, kidney beans, chopped tomatoes and brown rice
Wholegrain or granary toast with peanut or other nut butter and 100% fruit juice (150ml) Chicken and salad sandwich, using wholemeal bread or wrap Salmon with boiled new potatoes (skins on) and vegetables
2 thick slices of wholemeal toast with scrambled egg, a grilled tomato Lentil and vegetable soup with whole wheat roll Stir fry – whole wheat noodles, lean meat (chicken, turkey or beef), tofu or prawns and vegetables.
Low fat greek or plain yogurt with banana, berries, seeds and cereal (e.g. oats) Couscous or quinoa salad with chicken, roasted vegetables and kale Fish pie (potato topping) with green vegetables

 

 

Common sports nutrition questions

 

Do I need to take protein shakes and supplements?

  • Among recreational gym-goers, protein supplementation has become increasingly popular for muscle building, but is generally unnecessary.
  • For most active people the body’s protein needs can be easily achieved from a healthy, varied diet, with good choices of high quality, lean protein foods being incorporated into meals and snacks.
  • After competition sports or an intense training session, high quality protein powders can be a more convenient and transportable recovery method when there is limited access to food, and may be effective for maintenance, growth and repair of muscle.
  • However, unlike protein supplements, high protein foods will typically also contain essential vitamins and minerals.
  • A whey protein shake contains around 20g of protein – 20g of protein equates to half a chicken breast or a small can of tuna.
  • Taking protein far in excess of requirements through high intake of protein supplements may cause long term health risks (e.g. may increase the risk of poorer bone health and osteoporosis or accelerate any existing kidney problems).

 

When exercising, should I drink anything other than water?

In most cases, for exercise and activities up to one hour, water is sufficient for hydration. For exercise that is longer and more intense, other types of drinks may be considered.

  • Sports drinks: Isotonic sports drinks contain carbohydrates in the form of glucose, as well as electrolytes such as sodium. The electrolyte sodium will replace any lost from sweating and enhance rehydration, and glucose will replenish carbohydrate stores. Sports drinks have been shown to help endurance performance for active individuals performing endurance exercise (e.g. participating in a marathon). However, remember that sports drinks are similar to other soft drinks that contain sugars. This means that they can be high in calories and contribute to tooth decay, so they are only suitable if taking part in high-level endurance sports or if sweat loss is high.

Sports drinks can be expensive compared to other drinks; however it is easy to make them yourself! To make your own isotonic sports drink, mix: 200ml fruit squash, 800ml water and a pinch of salt.

  • Milk: Skimmed or semi-skimmed milk has been shown as an excellent post-exercise recovery drink. It naturally contains vitamins and minerals that can replace those lost via sweating and enhance rehydration (sodium), as well as assisting in muscle function and bone health (potassium and calcium). It also naturally contains high quality protein and some carbohydrates, and is relatively cheap to buy.
  • Energy drinks: Many people think sports drinks and energy drinks are the same, but it is important to note that they are very different. Energy drinks typically contain high levels of caffeine and sugars. They are not designed to replace the electrolytes lost in sweat and may contain other ingredients with stimulant properties. If consumed in excess, energy drinks can lead to severe health problems such as heart problems (cardiac rhythmic disturbances) and caffeine intoxication. As some are high in sugars, they can increase the risk of tooth decay especially in those with poor dental hygiene and could encourage high calorie intakes, which may cause weight gain. Energy drinks should not be consumed in place of sports drinks during exercise.

 

Should I take vitamin or mineral supplements?

  • Consumption of a healthy, varied, nutrient-rich diet, which contains plenty of fruits, vegetables, starchy foods, some lean protein foods and some low fat dairy foods, should provide all the vitamins and minerals that most physically active individuals require.
  • There is little evidence to suggest that vitamin and mineral supplements, if you are consuming a healthy, balanced diet, can improve performance.
  • Similarly, poor food choices cannot be compensated for by taking supplements. Supplements can be expensive and in very high doses can actually be harmful.
  • However, supplements may be necessary for certain population groups. For example, vitamin D is mostly obtained through action of sunlight on our skin in the summer months, and there are few rich food sources, so some at risk groups such as children under five years, pregnant and breastfeeding women and adults over the age of 65 are recommended to take a supplement.
  • Always consult your GP or a dietitian if you are concerned about a nutrient deficiency.