When dieting is a risky business
Issue: Volume 28 Number 2
Playing sport is fun and vital for overall health and fitness, but even the safest sports have an element of risk. In fact, risk is what often attracts people to sport; from those who put their pride on the line for the buzz of competing to thrill-seeking skydivers. It may seem surprising, but all sports participation contains a hidden risk — poor nutrition.
The challenge of meeting additional fuel or nutrient demands during training, the need to reduce body fat or ‘make weight’ just to compete, and even the type of diet, lifestyle or culture that surrounds a sport can all pose problems. Athletes requiring therapeutic diets to treat medical problems need to be particularly careful to ensure their diets meet both medical and sports nutrition goals.
Four groups of athletes who commonly are at an increased risk of nutritional problems are:
- vegetarians who have a poor understanding of how to balance their diet without meat
- people living away from home for the first time
- those with allergies, food intolerances or special medical conditions
- fad dieters.
Vegetarian athletes
Some athletes follow a vegetarian diet for religious, philosophical or environmental reasons. Others believe a vegetarian diet will enhance their performance or assist their battle with weight control (Australian Institute of Sport 2002).
There are four common types of vegetarian (Cox 2000):
- Semi-vegetarians exclude red meat and chicken from their diet, but eat fish and seafood.
- Lacto-ovo diets exclude all animal products, except dairy products and eggs.
- Lacto diets exclude all animal products, except dairy.
- Vegans exclude all animal products.
What are the risks of a vegetarian diet?
Energy and protein intake
A well-balanced vegetarian diet is generally healthy and adequate for most athletes. In fact, vegetarian diets tend to be low in fat and high in carbohydrates, which is beneficial to athletes. However, the high fibre content also makes them easily filling, so eating enough energy foods can be a problem.
Young vegetarian athletes who have high-energy needs due to rapid growth, participation in endurance sports, or who wish to gain muscle mass often have problems meeting those energy needs. Protein intake is generally adequate in a balanced vegetarian diet as the daily combination of grains, legumes, nuts and seeds support a wide variety of high-quality protein (Messina and Messina 1996). This is especially the case if dairy foods and eggs are also consumed. However, if eating enough food is a problem, then protein intake may be inadequate and may increase the risk for lean tissue loss. This can be a major issue for vegetarian athletes participating in sports in which they need to restrict their energy intake, either to make weight or for aesthetic reasons (for example, gymnastics and ballet).
Iron
Iron is arguably the nutrient most at risk in a vegetarian diet. Meat provides a source of haem iron, which is absorbed more effectively than the non-haem iron from grains and vegetables. Iron status can be enhanced by consuming foods rich in vitamin C and by avoiding iron inhibitors such as the tannins in tea and, to a lesser extent, the caffeine in coffee and cola drinks (Deakin 2000).
Iron deficiency is also a common nutrition problem for women and girls, particularly athletes participating in heavy training. Regular monitoring of blood iron levels may be important for many athletes in hard training.
Calcium
Obtaining sufficient calcium can be a challenge for those vegetarians not consuming dairy foods. Poor calcium intake can increase the risk of low bone density, thereby increasing the risk of fracture (Sports Dietitians Australia 2000). Calcium-fortified soymilks are an excellent alternative to dairy products (Weaver, Proulx and Heaney 1999).
Vitamin B12
Vegan diets tend to lack vitamin B12, so supplemental B12 from a fortified soymilk or dietary supplement is recommended. Vegetarian athletes should discuss whether they need a B12 supplement with their GP or dietitian.
Zinc
Inadequate zinc intake may compromise immune function and the healing of wounds (Clarkson 1991). Meat, chicken and fish are the major dietary sources of zinc, and thus the vegetarian athlete needs to consume alternatives such as whole grains, nuts and seeds, and legumes.
Nutritional deficiencies of protein, iron, calcium, or vitamin B12 may adversely affect performance by reducing energy levels, delaying recovery and inhibiting muscle repair and growth.
Athletes living away from home for the first time
Many athletes leave home at some stage to follow their sporting aspirations. This move, while positive for their careers, can cause some difficulties in their personal lives. Budgeting, shopping and cooking, in addition to the pressures of training, study or work can be daunting for those with limited nutritional knowledge and inexperience with meal preparation. This is a recipe for poor nutrition status, as athletes often become reliant on takeaway and highly processed foods, which are often low in variety and nutrients. Left struggling, these athletes fail to achieve peak performance and may often experience unnecessary fatigue or illness.
Most professional teams, sports academies and institutes enlist the assistance of a sports dietitian to support the needs of athletes living away from home for the first time.
Athlete support services range from lectures and workshops on sports nutrition to advice on shopping and hands-on cooking sessions that focus on the planning and preparation of healthy, simple, sports-friendly meals. Professional teams usually provide additional support by making sports drinks, snacks and recovery foods available at training venues to help these athletes stay fuelled when on the run.
Athletes with allergies, food intolerances or special medical conditions
Food allergies and intolerances
The treatment of food allergies and intolerances is a challenging area of medicine and dietetics. True food allergies are not common, and fortunately they are usually diagnosed at a young age so most athletes are aware of how to avoid and manage serious reactions.
Food intolerance is more prevalent than allergies, but harder to diagnose as individuals can have varying levels of tolerance to natural chemicals found in food.
Allergy - A reaction to a food protein. Symptoms can include facial swelling, skin rashes or hives, vomiting, diarrhoea and problems with breathing. Can be serious, even life-threatening, in highly sensitive individuals (Australian Dairy Corporation 2002).
Intolerance - A reaction to natural chemicals in food. Symptomscan include migraine, fatigue, muscle aches, asthma, diarrhoea, nausea and behavioural problems in children (Dalton 2001).
Unfortunately, athletes suffering from food allergies or intolerances often overly restrict their diet in fear of provoking a reaction. While this is understandable, unnecessary restriction increases the risk of nutrient deficiencies. Accurate diagnosis of food allergy or intolerance requires a team approach by allergy medical specialists and dietitians, but unfortunately, many people self-treat or consult unqualified practitioners. This delays a clear diagnosis and may result in prolonged and unnecessary avoidance of important food groups.
Other medical conditions
Athletes with medical conditions that require dietary treatment, such as diabetes, benefit from individual dietary counselling by a sports dietitian to ensure their medical and sports nutrition goals are met.
Fad dieters
Weight loss and the pursuit of better health can lead some people to pursue diet crazes that lack scientific validation. A popular diet at the moment is the low carbohydrate diet, which promises rapid weight loss, often by promoting unlimited fat intake. This diet is unsustainable and unhealthy in the longer term, and is therefore not suitable, nor recommended, for anyone, let alone active sportspeople.
The problems with a diet such as the low carbohydrate diet are similar to some of those discussed above. Most importantly, consumption of foods with insufficient carbohydrate value results in muscle carbohydrate (glycogen) depletion, as well as fluid and muscle loss as the body turns to its own protein sources for energy. This can be seen as rapid weight loss, but when the diet returns to normal, the lowered metabolism can encourage greater storage of body fat and increase weight. These diets also eliminate foods with beneficial vitamins and other nutrients, which can further hamper energy levels and subsequent performance.
Many athletes restrict — rather than cut out — certain types of carbohydrate from their diet as they learn more about the new way of classifying carbohydrate-rich food and fluids, known as the Glycaemic Index (GI).
Low GI foods are an important component of a healthy, balanced diet, but for athletes high GI foods are appropriate when the body requires an immediate source of energy. Athletes should consult a sports dietitian to help them assess the appropriate use of the GI in their diet.
The Glycaemic Index
Slowly absorbed foods and fluids are said to have a low Glycaemic Index, while foods that release glucose quickly into the bloodstream have a high Glycaemic Index.
Common signs of athletes following a fad diet include:
- a lack of energy, or less energy than normal
- fussiness about the foods they consume, and sometimes refusing to eat out
- obsessive talking about the diet they are following, and an unwillingness to listen to anyone having opposing views on the diet
- a lack of confidence in their appearance and a desire to find a ‘quick fix’ for weight loss
- low iron stores, as well as deficiencies in other vitamins and minerals.
Practical tips for coaches
- Make sure your athletes eat a healthy breakfast every day. This is an essential step in meeting daily energy needs.
- Encourage your athletes to include carbohydrates such as pasta, rice, potato, wholegrain bread and noodles in their diet, as these make the ideal basis for every meal and are usually relatively cheap and easy to prepare.
- Encourage regular trips to the supermarket; this will help keep grocery bills down, particularly if snacks and lunch can be prepared from foods at home rather than bought on the run.
- Encourage any athlete following a special diet to seek advice from a sports dietitian.
In conclusion, it is important that coaches:
- support and respect the individual needs and food preferences of athletes
- provide education on nutrition and food preparation skills for athletes living away from home for the first time
- offer tailored dietetic advice for athletes who follow special diets for medical or personal reasons.
Useful contacts for coaches
Sports Dietitians Australia — Tel: (03) 9425 0014 or www.sportsdietitians.com
Dietitians Association of Australia — Tel: (02) 6282 9555 or www.daa.asn.au
Australian Vegetarian Society — www.moreinfo.com.au/avs
International Vegetarian Union — www.ivu.org
References
Australian Dairy Corporation 2002, ‘Food Allergy: good health tips’, fact sheet, Australian Dairy Corporation, [place of publication?]
Australian Institute of Sport 2002, ‘Hot Topics in Sports Nutrition: vegetarian eating’, fact sheet, Australian Sports Commission, Canberra, viewed 27 March 2002, www.ais.org.au/nutrition/FactVege.htm
Clarkson PM, 1991, ‘Vitamins and trace minerals’, Perspectives in Exercise Science and Sports Medicine, 4, pp. 123–82.
Cox, G 2000, ‘Special needs: the vegetarian athlete’, in L Burke and V Deakin (eds), Clinical Sports Nutrition, 2nd edn, McGraw-Hill, Sydney, pp. 656–71.
Deakin, V 2000, ‘Iron depletion in athletes’, in L Burke and V Deakin (eds), Clinical Sports Nutrition, 2nd edn, McGraw-Hill, Sydney, pp. 273–311.
Dalton , V 2001, ‘Making food work for you!’ Boroondara health seminar series. [ publication details required ]
Messina, MJ and Messina, VL 1996, The Dietitian’s Guide to Vegetarian Diets: issues and applications, Aspen Publishers, Gaithersburg, MD.
Sports Dietitians Australia 2000, Bone Health: fact sheet no. 10, www.sportsdietitians.com
Weaver, CM, Proulx, WR and Heaney, R 1999, ‘Choices for achieving adequate dietary calcium with a vegetarian diet’, American Journal of Clinical Nutrition 70(3), pp. 543S–48S.
This article has been reviewed by Sports Dietitians Australia www.sportsdietitians.com.
For more information on the author or Sports Dietitians Australia, please visit www.sportsdietitians.com or email Alison Walsh on alisonwalsh@optusnet.com.au
This article is reproduced with the permission of the editorial team at Coaches' Edge, a free web-based newsletter that publishes the latest research in hydration, nutrition, training, injury management and mental preparation, among others. To join Coaches' Edge log on to www.coachesedge.com.au.
