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Specific nutrition for runners Running is a versatile sport that can range from a slow 2 km stroll to a fast 10 km race or even a long ultra-distance event. People run for different reasons but whether it is competitive, recreational or social, running remain a moderate to high intensity activity that requires energy and a sound nutrition plan.
Energy for optimal performance and recovery
If you are a social or recreational runner, training to stay healthy and fit, you probably do two to four 30 to 60 minute runs during the week plus a longer run or race over the weekend. You might accumulate a weekly distance of 30 to 50 km and perhaps even up to 80 km if you are training for a marathon. If you are running 40 km per week at an average speed of five minutes per kilometre, this adds up to 200 minutes of running. For a person that weighs 65 kg, approximately 11 000 additional kilojoules (2 619 kcal) is required per week. This means you need to add an extra 1 680 kilojoules (400 kcal) to your baseline energy requirements of 10 000 kilojoules (2 400 kcal) per day. Elite distance runners and athletes training for ultra distance events such as the Comrades marathon need up to 7 800 extra kilojoules (1 850 kcal) daily. The bottom line is that running requires lots of energy. To maintain a regular running programme without running out of fuel, getting sick or feeling constantly fatigued it is important to consume enough energy, especially carbohydrates. Carbohydrates are the preferred fuel during running and if you are not well stocked with carbohydrates, you will not run well. Recovery nutrition after a run is also important especially if you are running more than once a day, if your run is less than 24 hours away or if you had a long hard run in the heat. Iron deficiency Distance runners, particularly females, often have a low-iron status. Running increases iron requirements as a result of increased iron losses through sweat and gastrointestinal bleeding, decreased iron absorption and the physical destructive impact of running on the red blood cells. Female runners are at a greater risk for iron deficiency due to additional iron losses during menstruation plus they often have inadequate dietary iron intakes. If you are suffering from extreme tiredness, lagging race performances and poor recovery from training, it is worth assessing your daily iron intakes. The recommended daily intake for women is 18 mg per day and 8 mg per day for men. There are two different forms of iron in food, called heme and non-heme iron. Heme iron is found in meat, fish and poultry and is better absorbed than the non-heme form that is found in plant products. Vitamin C enhances non-heme iron absorption, therefore plant products containing non-heme iron eg spinach should be consumed with foods or drinks containing Vitamin C. Tannins (found in tea), caffeine and too much fibre on the other hand, inhibit iron absorption. Iron supplementation may be required if you are iron deficient but should never be used without a proper diagnosis as these supplements can have side effects. Examples of foods rich in iron Food source Amount of iron (mg) Cooked lean steak 3.2 mg per 100g Cooked liver 6.3 mg per 100g Cooked chicken (dark meat) 1.3 mg per 100g Oysters 6.7 mg per 100g Fortified breakfast cereal 4.2 mg per ¾ cup Cooked spinach 3.2 mg per ½ cup Tofu 5.4 mg per 100g Dried apricots 2.4 mg per 50g Cooked soya 4.1 mg per 80g Amenorrhoea, low bone density and stress fractures It is not uncommon for female long distance runners to suffer from menstrual irregularities, fail to start menstruating or to stop menstruating all together (amenorrhoea). The causes of amenorrhoea are multi-factorial but excessive training and very low body fat levels are amongst the main risk factors. Elite female runners often consume too little energy to match their training programmes and fail to sustain normal, healthy body fat levels. In addition, many female runners set unrealistic body weight targets to be thinner and faster. We now know that low oestrogen levels in amenorrhoeic female athletes can lead to loss in bone density and bone strength and increase the risk of stress fractures. It is very important that female runners consume sufficient energy to sustain normal body fat levels.
The importance of calcium
Calcium is the most important 'bone health' mineral for male and female runners as a low calcium intake can predispose you to stress fractures, osteopenia and osteoporosis. The recommended daily intake is 1 000 mg/day for 18 to 50 year-old runners. Females with amenorrhoea or menstrual irregularities should consume 1 500 mg/day but may also need to use low-dose oral contraceptives with the hormone oestrogen as this increases calcium absorption. Runners that are younger than 18 or older than 50, as well as pregnant women need to consume more calcium. Foods that provide a good source of calcium include dairy products, sardines and pilchards eaten with the bones. The calcium content of certain foods Food source Amount of calcium (mg) Full cream milk 297 mg per 250 ml Low-fat yoghurt 266 mg per 175 ml Skimmed milk 307 mg per 250 ml Cheddar cheese 216 mg per 30 g Ricotta cheese 334 mg for ½ cup Sardines 315 mg per 80 g Tofu 105 mg per 100 g Spinach (cooked) 122 mg per ½ cup Oranges 72 mg per medium orange Gastrointestinal (GI) problems Running is a weight-bearing activity that involves the up and down movement of the whole body, including the stomach and stomach contents. Apart from the annoying 'sloshing' sound of fluids in the stomach while running, a full stomach can cause gastrointestinal discomfort on a run. Consuming certain foods and fluids before and/or during a run can also cause stomach upset including cramps, diarrhoea, heartburn and wind. The cause of these problems is not 100% clear and may vary from runner to runner. Inexperienced runners as well as older runners are more prone to suffer from GI problems. It is important to experiment with the type and timing of food and liquids that you consume before and during a run. Some factors that have been shown to be associated with GI problems during running: · Beverages with a very high fructose content ie fruit juices and concentrated carbohydrate drinks (>10%) · Hyper-osmotic drinks (eg drinks containing high concentrations of electrolytes) · Gas-forming foods (ie beans, asparagus etc), high-fat foods, high fibre foods and even protein · Running at a fast pace or racing for a personal best has also been associated with gut discomfort and stitches. Runners sensitive to lactose should avoid milk products before or during a run and runners suffering from heartburn should take smaller sips more often when running. Top tips for runners · Eat enough carbohydrates to sustain energy levels while you are training and racing. Supplements such as carbohydrate drinks, carbohydrate powders, corn syrups, gels and energy bars are useful. Liquid meal replacements are ideal when you have little appetite. · In your day-to-day diet, select carbohydrates that are nutritious. Opt for pasta, potatoes and rice as opposed to sugary sweets and fizzy drinks. · Have a recovery plan. Eat a low-fat recovery snack containing carbohydrates and protein within an hour of completing a training run or race. Limit or preferably avoid drinking alcohol immediately after a run as alcohol interferes with glycogen restoration, increases urine output and can delay recovery. · Choose protein foods and take the iron and calcium value into consideration. Generally, meats are rich in iron and dairy-foods are rich in calcium. · Experiment with foods and fluids during your training runs to avoid stomach upset, cramps and stitches during a race. · Pay attention to your fluid intake. Drink when you are thirsty and stay hydrated at all times. · When injured or resting, cut your energy intake accordingly. Cut back on those extra carbohydrates and choose fat-free or low-fat diary products and lean meats. Eat plenty of fresh fruits and vegetables. · Avoid fad diets especially diets that are very low in carbohydrates ie the Atkins diet. This will not only affect your running but will also compromise your immune system. · Eat regularly during the day. This will help you to avoid hunger pangs and prevent you from over-indulging during lunch or dinner. You will also sustain your energy levels during the day. · Run early in the morning and add sprints to your run to boost your metabolism. (Info reworked from Discovery) |