Obesity: A briefing for Complementary Therapists
Nutritional Needs of the Vegetarian Sportsperson
by Jenni Herbert
Any sportsperson needs to support his or her training programme with the right kind of nutrition, both qualitative and quantitative. Athletes put themselves under severe physical and mental stress, which causes the body to react in a number of ways, releasing larger than normal quantities of hormones into the bloodstream. The combination of extreme physical activity, severe mental stress and increased metabolic demands of the body associated with the high level of hormones in the blood creates a need for larger quantities of proteins, carbohydrates, fats, minerals and vitamins along with trace elements and micronutrients. Because larger quantities of nutritional elements are required, considerable pressure is placed on the digestive and assimilative processes. Food must be very carefully selected so as to be adequate in quantity, appropriate in quality and of minimal toxic value.
The vegetarian athlete faces many specific challenges. As outlined above, proper nutrition will directly affect athletic performance and vegetarians in particular need to plan ahead and ensure that there is adequate variety in their diet. The primary concern for the vegetarian athlete, and particularly the vegan, is obtaining adequate energy and protein. A high carbohydrate diet is essential to optimise muscle glycogen stores, which are the preferred source of energy during prolonged activity. Generally speaking, exercising for longer than 90 minutes will require carbohydrates afterwards to replace glycogen and protein will be necessary to repair damaged muscle tissue. It is crucial to obtain adequate carbohydrate for energy so protein is not used as an energy source. For sports purposes, the vegetarian diet may lack adequate energy, protein, calcium, zinc, iron, B6, and B12.
Protein
Protein is needed for tissue repair, building and repairing muscles, building red blood cells and synthesizing hormones and enzymes. Protein requirements are no different for the vegetarian athlete: 1.2 to 2 gm protein per kg. of body weight is required depending on sport and duration. Vegetarian sources of protein are superior to non-vegetarian sources in that they contain all the necessary ingredients and in their utilizable forms. Non-vegetarian sources of protein, though being individually far superior to vegetarian sources of protein, offset this advantage by producing more toxins during metabolism as they are harder to assimilate and therefore are prone to a certain amount of fermentation in the gut.
Proteins are made up of smaller units called amino acids. Proteins are broken down into their constituent amino acids during digestion which are then absorbed and used to make new proteins in the body. Certain amino acids can be made by the human body. However, there are 8 essential amino acids which cannot be made and so they must be supplied in the diet. The essential amino acids are leucine, isoleucine, valine, threonine, methionine, phenylalanine, tryptophan, and lysine. For children, histidine is also considered to be an essential amino acid.
Unlike animal proteins, plant proteins may not contain all the essential amino acids in the necessary proportions. However, a varied vegetarian diet means a mixture of proteins are consumed, the amino acids in one protein compensating for the deficiencies of another. Vegetarians and vegans eating a well-balanced diet based on grains, pulses, seeds, nuts, soy and vegetables will be consuming a mixture of proteins that complement one another naturally. One challenge is that animal source proteins are also the only reliable source of Vitamin B12 so supplements must be taken. More on this in a minute.
Previously, it was thought that protein complementing needed to occur within a single meal. However, it is now believed that this is not necessary as the body keeps a short-term store of the essential amino acids. A well-balanced vegetarian or vegan diet will easily supply all the protein and essential amino acids needed by the body. Vegetarian diets are higher in branched chain amino acids (BCAA), the amino acids used by muscle during activity. They prevent protein breakdown and help muscles recover quicker. If glycogen stores are low, the use of protein for energy increases. The BCAAs are readily available to the muscles for energy.
Carbohydrates
Carbohydrates (mostly sugars, starches and cellulose) should constitute at least 50% of the calories consumed daily. For vegetarian sportspeople this figure can be as high as 65%. Natural carbohydrate sources such as fruits, vegetables and grains are to be preferred because in the natural form they are in combination with the appropriate vitamins which act as co-factors in their metabolism. Furthermore, natural carbohydrates exist alongside fibre, retarding their absorption and thus avoiding large fluctuations in blood sugars. Honey is an excellent source of carbohydrates for athletes as it is quickly converted to glycogen and stored in the liver.
Fats
Fats are essential for the metabolism of various vitamins (A,D,E,K), immune function, nerve myelination, repair of the body tissues and as a source of energy during periods of high demand associated with starvation (as in the marathon runner). In fats, of particular importance are essential fatty acids such as Iinoleic acid, linolenic acid and arachidonic acid. Weight for weight, the vegetarian sources of fats and fatty acids are very good.
Minerals and Vitamins
All vitamins and minerals are important. The two which are probably of most importance to athletes are calcium and iron.
Calcium is essential for all athletes but a vegan needs to plan sources from plants or supplement in the diet. Athletes with low dietary calcium may have increased risk of bone fractures and stress fractures. Vegetarian athletes should aim for 1,000 milligrams (mg) of calcium day through diet and/or supplements.
All athletes (especially females) are at risk of iron deficiency. Iron loss is increased during heavy training. Iron is an essential part of red blood cells that helps transport oxygen to the muscles. The main symptoms of deficiency in an athlete are weakness and rapid fatigue upon exertion. Vegetarian sources of iron are less well absorbed than meat sources. 18mg of iron per day should be the goal for the female vegetarian athlete and at least 10mg for men. Vitamin C significantly improves iron absorption.
Riboflavin B2 and B12 are two B-vitamins to be concerned about in the vegetarian diet. Riboflavin intake is low in vegans, mainly because there are no dairy products consumed. Riboflavin is essential for the production of energy and therefore essential to athletic performance. B12 is needed for production of normal red blood cells and deficiency can result in anaemia. As we said earlier, vitamin B12 can only be found in animal products so vegetarians and vegans need to take a B12 supplement.
Pre-workout Eating
The meal eaten preceding a workout should not be larger than 800 calories eaten about 4 hours prior and should include high-carbohydrate, low-fat foods, protein and vegetables/fruits. Too much of any one type of food, such as protein or fibre, can cause nausea or heartburn. In addition, it is advisable to ensure that some food (a 200 calorie snack or meal) is eaten at least one hour before working out as the athlete will not perform at their best if hungry or with low glycogen stores.
Eating During The Workout
Replacing both fluid and carbohydrate during prolonged exercise is important. What and how much to replace depends on the type, duration, and intensity of the exercise. Adequate fluid intake is the single most important recommendation for all types of exercise. The general recommendation is to drink 1/2 to 1 cup of water every 10 to 20 minutes. In a hot environment, when perspiration is especially heavy, drinking up to 2 cups of water every 15 minutes may be necessary to replace fluid losses. Adequate hydration enables the active body to regulate its temperature effectively and allows for good circulation and muscle function.
Carbohydrate replacement is necessary in events lasting longer than 90 minutes and may even be beneficial during high intensity exercise of shorter duration. Consuming carbohydrates during exercise increases both the time and the intensity the athlete is able to exercise before becoming exhausted. However remember that digestion will not work efficiently during exercise.
Post-workout Eating
The meal following a workout is nutritionally the most important meal for aiding recovery from exercise and maintaining the ability to train on the following days. Fluid, carbohydrate, and protein intake after exercise is critical, especially after heavy exercise. A high carbohydrate intake is required to replace depleted muscle glycogen stores. Eating protein may also aid in repairing and rebuilding damaged muscle tissue. Exercise significantly alters protein metabolism, especially as the exercise becomes more prolonged and more strenuous. Since the body begins to replace its depleted stores and repair any microscopic damage to muscle fibres almost immediately after exercise, provision of these depleted nutrients in the post-event meal may accelerate recovery. Delaying the ingestion of carbohydrates by several hours slows down the rate at which the body is able to store glycogen.
Benefits of the Vegetarian Diet
In summary, the nutrition of an athlete is not simply an ‘eat-more’ phenomenon. The quality is as important as the quantity, if not more.
Although a vegetarian diet cannot supply all of our needs, the benefits of a predominantly plant-based diet are numerous. Plants are packed with vitamins and minerals, phytochemicals, antioxidants, essential fatty acids and branched chain amino acids. With proper planning and adequate supplementation, the vegetarian can have a healthy diet that meets the nutritional needs for athletic performance.
The timing of food and the changes of in-season and off-season nutrition are also important because it helps athletes to build up their reserves during off-season and hence have them prepared for in-season, high level energy expenditures.
Bibliography
Vegetarian Sports Nutrition by Enette Larson-Meyer
Vegan + Sports: Vegan Nutrition and Endurance Sports by Arnold Wiegand
The Vegetarian Sports Nutrition Guide: Peak Performance for Everyone from Beginners to Gold Medallists by Lisa Dorfman
Adirondack Sports & Fitness magazine
The Vegetarian Resource Group (www.vrg.org)
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