As a female endurance athlete, who is training hard and racing regularly, your nutritional needs are not the same as your typical sedentary or even regular gym-going woman. You are making higher demands on your body, and this requires more fuel, in the form of carbohydrates and fats, more “building blocks” from protein to enable repair and recovery, and a greater amount of micronutrients, eg vitamins, minerals and phytonutrients, to help facilitate your body’s various metabolic processes and maintain good health. Your nutritional requirements are also different in some aspects from those of male endurance athletes. For example, women have a greater need for iron due to blood losses from menstruation, and it is also thought that they are able to oxidise a greater amount of stored fat than men, lessening their reliance on glycogen.1
Some hard-training women also find themselves caught in what is known as the Female Athlete Triad, where they experience ‘disordered eating’ that leads to amenorrhoea (loss of monthly periods) and a reduction in bone density, which makes them more prone to injuries like stress fractures and puts them at risk of developing osteoporosis. This unhealthy situation is usually triggered by a desire to lose weight and/or body fat and a consequent restriction of both calories and nutrients, which in turn eventually adversely affects both performance and health. The existence and consequences of the Female Athlete Triad was documented in a position stand by the American College of Sports Medicine in 1997. 2
Here’s my list of common nutritional issues experienced by female endurance athletes, and some tips on how to avoid them:
1. Inadequate calorie intake
You may feel under pressure to lose weight or body fat in order to improve performance, and start cutting calories. This can result in a shortage of vitamins and minerals as well as reduce energy levels. You can also become obsessed about food and your diet, which may develop into disordered eating patterns, as mentioned above.
My tips: focus on eating nutrient dense foods such as vegetables, eggs, fish, lean meats, nuts and seeds and legumes, while timing your intake of fruit and wholegrains around your training (before to provide energy and after to promote glycogen re-synthesis). Losing 1lb of body fat per week in the off-season is a healthy target for an endurance athlete. Avoid counting calories.
2 Not consuming enough healthy fats
Don’t be afraid of eating fats from natural sources. Your body needs fat to function: around 60% of your brain is composed of fat, for example. Fats are required for hormone, nervous system and immune function, and are also used for energy at low intensities. Around 30% of the calories in your diet should come from a mixture of saturated, monounsaturated and polyunsaturated fats.
My tips: eat 5-6 of the following each day, choosing as wide a range of different foods as possible across the week – half an avocado, 100g of oily fish like salmon or mackerel, 30g of mixed plain nuts, a teaspoon of sunflower, pumpkin seeds or sesame seeds, a teaspoon of chia seeds or ground flax seed, a tablespoon of extra virgin olive oil or hempseed oil in a salad dressing, a tablespoon of coconut oil or butter in cooking, a tablespoon of almond or cashew nut butter, 150g of plain yogurt (full or low fat, not zero fat which is likely to be high in sugar), 60g of cheese. Avoid all fats found in processed foods.
3. Having inadequate iron in your diet.
Anaemia, or a low level of iron in the blood, is very common in female athletes. In some cases this is actually what is known as ‘sports anaemia’, a result of regular aerobic training which increases the volume of blood plasma and so “waters down” the amount of haemoglobin (the iron-containing pigment in red blood cells) and ferritin (the protein storing iron) in the blood. This type of anaemia does not respond to taking iron supplements and should not affect performance. 3 However, athletes may also experience ‘iron deficiency anaemia’, characterised by symptoms such as fatigue, headaches, light-headedness and unusual breathlessness during exercise. This can adversely affect performance. Once diagnosed, iron supplements are likely to be prescribed by a doctor. This type of anaemia is more common among vegetarians, as less of the iron found in plants (non-haem) is absorbed into the bloodstream than that found in meat (haem).
My tips: if you eat meat, choose the best quality lean red meat you can afford (preferably grass fed) and have it once or twice a week. If you are vegetarian, include 6-8 eggs in your diet each week as well as plant sources of iron like lentils, beans, pumpkin seeds, tofu and dried apricots. These should be eaten with a source of vitamin C, eg fruit or vegetables, to improve absorption. If you are vegan, add a tablespoon of blackstrap molasses to your diet each day as well as eating plenty of plant sources of iron.
4. Not having enough bone supporting nutrients
The physical action of endurance sport, particularly running, combined with the stress of training, puts your bones under a great deal of pressure and increases the need for bone-building nutrients like calcium, magnesium, boron and vitamins D and K. If training is combined with a low calorie intake and low body fat levels, and menstrual dysfunction is also experienced, bone health can be compromised. A lack of minerals and low levels of the sex hormones oestrogen and progesterone results in a lowering of bone density. This leads in turn to an increased risk of stress fractures and a slowing of recovery time from injury.
My tips: eat dairy products, or fortified alternatives like rice or coconut milk, for calcium but balance this out with plenty of sources of magnesium such as green leafy vegetables (also good for calcium and vitamin K), nuts and seeds, beans and lentils, and wholegrains. If you have a history of fractures, get both your calcium and vitamin D levels tested. But don’t take a supplement containing only calcium: it can interfere with the absorption of zinc and iron. Go for a broad-based bone health supplement instead, including at least magnesium, vitamins D & K, and boron.
Jo Scott-Dalgleish BSc (Hons) is a BANT Registered Nutritionist, writing and giving talks about nutrition for endurance sport. Based in London, she also works as a Registered Nutritional Therapist, conducting one–to–one consultations with triathletes, distance runners and cyclists to help them eat well, be healthy and perform better through the creation of an individual nutritional plan. To learn more about these consultations, please visit www.nutritionforendurancesports.co.uk
1 Volek et al. Nutritional aspects of women strength athletes. Br J Sports Med. 2006; 40: 742-8
2 Otis et al. American College of Sports Medicine Position Stand: the Female Athlete Triad. Med Sci Sport Exerc. 1997; 29: i-ix
3 Bean, Anita. The Complete Guide to Sports Nutrition. 7th Edition (2013), Bloomsbury, London: pages 179-`182