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CARBOHYDRATES Carbohydrate is one of the most important nutrients to athletic performance. Carbohydrate plays the major role in supplying your brain and body with power. The body cannot supply enough carbohydrate on its own and therefore it needs to come from foods. Exercising with low levels of carbohydrate leads to fatigue. Carbohydrates are the ideal fuel for muscular work. Carbohydrate is stored as glycogen, which is stored in the muscles and liver. Liver glycogen is used to maintain blood sugar, which, in turn, fuels the brain, nervous system and other cells. Optimal blood sugar levels are important for clear, brain function and therefore critical to sharp, high speed mental performance. Low blood sugar results in weakness and fatigue. Muscle glycogen fuels muscle cells during exercise. Muscle glycogen and fat supply energy during endurance activities. Maximizing glycogen stores is one of the primary goals of sports nutrition. When exercising hard there is a continual loss of glycogen from the active skeletal muscle during the prolonged exercise. When the glycogen stores become depleted the athlete will not be able to exercise intensely and will experience fatigue. A gradual decline in muscle glycogen is related to the chronic fatigue often experienced by athletes during repetitive strenuous training conditions. Chronic fatigue often limits an athlete’s ability to comply with a progressive training program and subsequently to compete at maximal potential. If you do not eat enough carbohydrates to refill the stores that are depleted in each workout, you may not have enough carbohydrates available during ensuing workouts. Therefore, consuming carbohydrates during endurance exercise can postpone fatigue and prolong peak performance. Diet and endurance training influence the amount of glycogen stored in muscle and the time it takes to exhaustion. A high carbohydrate diet can raise the initial muscle glycogen concentration and thus there will be a greater time to exhaustion. Diet provides the body with the needed fuels, while training promotes muscles to store more carbohydrate and help improve the body's utilization of fuel. More muscle glycogen will help increase endurance. An individual that is more fit uses less glycogen, is better able to conserve the limited glycogen stores in the body, and utilizes more fat as a fuel source during endurance events. Athletes who follow a high-carbohydrate diet can maintain high-intensity exercise for a longer period than those on a lower-carbohydrate diet. There is substantial evidence for a benefit of carbohydrate intake for the performance of brief, high power events if the competitor has been consuming a reduced energy diet. Total carbohydrates are made up of simple sugars, complex carbohydrates, and fiber. Simple carbohydrates are commonly known as sugars. Sources of simple carbohydrates include table sugar, candies and other sweets, sodas and bakery goods. These foods provide empty calories, i.e., calories that supply no vitamins and minerals and should therefore be minimized. Complex carbohydrates include all the complex starches and fiber, such as those found in grains, cereals, breads and starchy vegetables like potatoes, corn, peas and beans. Milk, fruit and vegetables also contain carbohydrate. Complex carbohydrates contain many essential nutrients and are the body's most effective source of energy to the athlete. Complex carbohydrates increase glycogen stores more efficiently than sugars, or simple carbohydrates. Complex carbohydrates are ideal because they are quickly digested and absorbed into the bloodstream, leaving the stomach quickly so there is less chance of indigestion and nausea during the event. Carbohydrates should make up the largest portion of the athlete's diet. Research suggests that to maintain adequate carbohydrate stores during heavy training, carbohydrate intake should range from 7-10 grams/kg of body weight/day or 55-70% carbohydrate. Athletes who train exhaustively on successive days, or who compete in more prolonged endurance events, would benefit from a diet that contains 65% to 70% of total calories from carbohydrates. FAT Fats, like carbohydrates, are used by the body for fuel and are essential for the absorption of certain vitamins. The most important role of fat is to spare carbohydrates (which are in limited supply) in exercise of long duration and low intensity. Fat is a valuable metabolic fuel for muscle activity. Endurance training significantly increases the ability of muscle to utilize fat. During aerobic exercise, fat serves as the preferred fuel source for muscle activity, however, this relationship is not necessarily enhanced by increasing the dietary intake of fat. The endogenous body fat stores are more than adequate to meet these needs. Even the leanest athletes have sufficient fat storage to meet the metabolic demands of strenuous exercise. Consuming a high-fat diet will result in a larger proportion of fats used during exercise, but this limits the amount of carbohydrate storage, which ultimately limits endurance. Therefore high dietary fat intakes should be avoided. Also too much fat can lead to heart disease, obesity, cancer and other health problems. Fat intake for athletes, as well as healthy adults, should comprise less than 30% of total calories. Fats in the diet may be of animal or vegetable origin. Selecting lean meats, nonfat or low fat dairy products and limiting added fats such as butter, margarine, salad dressing, cream sauces, gravies and fried foods will help you achieve this goal. Carbohydrate Intake Targets for Athletes However, in situations where maximal glycogen storage is desirable and/or the athlete must meet the fuel bill of prolonged exercise sessions, carbohydrate needs become more specific. In these cases, the muscle has an absolute requirement for carbohydrate (see Table below). Therefore, it is preferable to set definite carbohydrate intake goals for athletes, scaled to take the size of the muscle mass into account (i.e., the athlete's body mass). The guideline to consume 7-10 grams of carbohydrate per kilogram body mass is not only considerate of the muscles needs, but is also user-friendly. It is relatively easy to use a ready reckoner of the carbohydrate content of foods to add up the fuel provided by a meal or a diet - for example, to reach a target amount of 50 g snack after training, or a daily intake of 400-600 g. It takes far more nutritional expertise to imagine what a dietary ratio of 50% or 60% or 70% carbohydrate looks like on a plate. With the advice of a sports dietitian, an athlete should be able to narrow their carbohydrate intake targets to specific levels for specific occasions. The absolute amount of carbohydrate required for optimal glycogen synthesis is greater than the typical intakes of most people, including athletes. And it may require an athlete not only to eat more carbohydrate (in grams), but to devote more of their total energy intake to fuel foods to do so. Typically, athletes need to earmark 50-70% of their energy intake to meet their carbohydrate needs. This is a wide range, because in real life the total energy needs and the muscle fuel needs of an athlete are not always synchronized. The "perfect" carbohydrate:energy ratio cannot be fixed. Athletes who have large muscle mass and heavy training programs usually have very high energy requirements. For these athletes, total intakes of 800-1000 grams of carbohydrate representing 8-10 grams per kilogram of body mass may be consumed from only 45% of their energy budget. Other athletes may need to devote 70% of a restricted energy budget to achieve a carbohydrate intake of even 6-7 grams per kilogram. This situation is particularly common in female athletes and others whose main dietary concern is to maintain lower body fat levels than seems natural. There is an unfortunate tendency of those working with athletes to regard carbohydrate intake guidelines as rigid. Many judge the fuel intake of an athlete or a group of athletes to be deficient or inadequate based on the percentage of energy derived from carbohydrate. Some sports nutrition guidelines, even from recognized bodies such as the American Dietetic Association, maintain the confusion because they set their dietary guidelines for athletes based on energy ratios. However this is inappropriate if the goal is to judge fuel intake, and this doesn't track closely with total energy needs. In the first situation described above, an athlete might be consuming a high total intake of carbohydrate, adequate to meet their fuel requirements. However, they will be judged to be following a low- or moderate-carbohydrate diet from the perspective of energy ratio. This often happens in the assessment of the diets of individual athletes, but has also led to some questionable interpretations of research data. Some studies have exposed athletes to so-called high or moderate (low) carbohydrate diets and compared metabolic and performance outcomes. They have found no differences between responses to the diets and concluded that high carbohydrate diets are not important for athletes. However, their moderate carbohydrate diets (40% carbohydrate) may have provided reasonably large amounts of carbohydrate, thanks to a high total energy intake. So, even the moderate carbohydrate diet met the fuel needs of the athlete. A high carbohydrate diet (80% of energy) may be superfluous for this group. Although total amounts of carbohydrate may be a better guide for assessing or setting goals for an athlete, they still must be regarded with some flexibility. In all areas of nutrition, judgments of adequacy or deficiency cannot be made from a single piece of evidence, particularly when it comes from a food record or another dietary survey tool. Dietary survey methods suffer from many errors of reliability and validity which generally lead to an underestimation of true dietary intake. For athletes who have important or increased carbohydrate needs, it is both more reliable and more practical to set guidelines in terms of a fixed amount of carbohydrate, rather an energy percentage.
PROTEIN
Protein is measured in grams amount in food
Structure of protein
The building blocks of protein. Essential amino acids cannot be made by the body. Must be supplied by the diet. a Lack of essential amino acids causes disease. Non-essential amino acids can be made in the body. Animal foods contain all the essential amino acids. Complete protein Essential Amino Acids (Building blocks of proteins)
Non- essential amino acids can be made in the liver if protein is adequate. Used to make body proteins example: phenyalanine can be changed into the non-essential amino acid tyrosine.This is a factor in the disease PKU Other uses of amino acids
example: soybean limited in methionine and infant formula fortified with it Amino acid supplements May lead to nutritional imbalances overload of a specific amino acid may inhibit absorption of others arginine, lysine and ornithine - taken to stimulate release of Human growth Hormone Growth Hormone - may increase LBM but not strength os size HGH or the amino acids arginine lysine and ornithine are not recommended used at a high rate by high school students and can potentially be a hazardous drug Tryptophan- studies do not show that improves athletic performance Incomplete protein: lack one or more essential amino acids. Found in vegetable proteins. Cannot lead to growth without combination at the same meal. Examples of incomplete being combined to make complete protein bread + peanut butter rice + beans seeds + legumes Terms related to protein quality high biologic value protein best arrangement of amino acids for used by the body found in eggs followed by milk complete protein contains all the essential amino acids found in animal foods only meat, milk, eggs, leads to growth Uses of protein in the body growth - needs of children higher than adults repair - increased following injury like broken bounds of wounds blood proteins - albumin, fibrinogen enzymes, hormones water balance - albumin acid-base balance - buffers energy if calories inadequate Digestion & absorption of protein begins in the stomach with enzyme pepsin continues in the small intestine with enzyme trypsin from the pancreas & protease from the small intestine breaks down into individual amino acids amino acids are absorbed into the blood stream first stop is the liver amino acids can be stored temporarily in the liver What happens in the liver? can be used by the body for growth & repair Amino acids can be organized into chains using the recipe provided by the DNA to make new proteins. This is the primary use for protein in the diet. If the body does not have a need for new protein or if the body needs energy amino acids can be taken further apart into carbon, hydrogen, oxygen and nitrogen - deamination Deamination: break down of amino acid takes place in the liver used to generate energy. Urea is a waste product from this process. Urea is eliminated from the body in the urine What is protein restricted in liver failure? because the liver if healthy makes urea urea is made from nitrogen from excess amino acids if a person eats normally with normal intakes of protein the liver will be unable to use the excess nitrogen to make urea the nitrogen remains in the blood and will cause problems for the patient Why is protein restricted in kidney disease? the liver continues to make urea from excess nitrogen from excess amino acids but the kidney cannot eliminate the urea urea increased in the blood and will cause uremic poisoning Recommended dietary allowance based on ideal body weight first convert ideal body weight to kilograms second multiple the weight in kg X .8grams/kg this is the total daily requirement for protein of healthy adults elderly need 1 gram/kg What happens if you do not get enough protein? Kwashiorkor: Over time the disease kwashiorkor can develop. Kwashiorkor is more commonly seen in the third world and in children. It is the disease the first child gets when the second child is born. Swollen belly, thin hair, skin loses pigment. Infection common, apathy and death Marasmus: if both protein and calories are inadequate the disease is called marasmus. Total wasting of the body. No swelling. Seen in third world and can be seen in the end stages of disease such as cancer or Alzheimer's disease The fuel you put in you body, carbohydrates, proteins, and fats, can be compared to the fuel that you put in your car, Supreme, Super, and Regular, respectively. In terms of energy, Carbohydrates from unprocessed, unrefined grains, fruits and vegetables have a "Supreme" octane rating. Protein from lean meats, poultry, fish, beans, soy, and low fat dairy has a "Super" rating. Fat from fish oil, flaxseed, and unsaturated vegetable origin has a "Regular" rating. The major difference here is that you should fill your body with all three sources of fuel at once. Consume "High Octane" carbohydrates first (unprocessed, unrefined), proteins second, and save the fat for last. As an athlete, your needs are unique. It is not enough to say that you need a certain percentage of carbohydrates and protein. Base your needs on body weight and level of training as follows (the more you train, the greater your needs):
Similar to your training routine, you should have an eating routine. The off-season is the time to build a base, not only with strokes, revolutions, and strides, but also with carbohydrates, proteins and fats. You cannot expect your body to excel if you neglect proper nutrition until 2 weeks prior to a race. You may have the high-octane fuel to complete the swim and to coast on the bike, but chances are you will not have the stored fuel to prevent you from "bonking" on the run. You will notice that I failed to mention the most important nutritional need for an athlete, water. I feel that you already know and have experienced the importance of being properly hydrated. I'll drink to that!! In terms of Race Day, you want to stick with what got you to the starting line thus far. Practice eating strategies during training so you have a plan for race day and you do not have to experiment. Recovery nutrition is vital. After those grueling workouts, you have a two-hour window to replace all the energy you just burned. Delaying carbohydrate intake past this window will impair recovery by reducing muscle glycogen. Although supplements may be more convenient and quick, there is no substitute for real food. You can base your needs on the following:
Consult a food coach, otherwise known as a Registered Dietitian who specializes in Sports Nutrition. (antioxidants, minerals, protein, and essential fatty acids) | ||||||||||||||||||||||||||||||||||||||||||||||
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