Sports Nutrition Lecture PDF

Al Ayesha Farooq FEM- HU   After it has been determined that weight or body fat loss is indicated for an athlete, a goal weight or body fat percentage should be determined. Sports nutrition professionals should help athletes avoid choosing an arbitrary goal weight and use ind...

Al Ayesha Farooq FEM- HU   After it has been determined that weight or body fat loss is indicated for an athlete, a goal weight or body fat percentage should be determined. Sports nutrition professionals should help athletes avoid choosing an arbitrary goal weight and use individual weight and body composition data to determine the best weight and body composition for each athlete individually.  Body mass index can be used initially to determine weight goals.  In using a BMI nomogram or online calculator, athletes plug their height and weight into the chart to determine their current BMI. Next, they can choose a weight on the chart that is one or more points below their current BMI or one that may correspond with a BMI in the normal range. The choice of a BMI goal weight depends greatly on  current BMI,  level of overweight or obesity,  weight history and/or history of recent weight gain,  Level of exercise, and commitment to a long-term weight management plan. The weight goal chosen also should fall within the general guideline of not losing more than 1–2 pounds per week and, or should fall within the goal of a 5– 10% loss of current body weigh  In many instances, athletes should use weight and body composition data to determine appropriate weight (fat) loss goals.  Athletes attempting to lose weight should have both BMI and body composition measured before starting a weight loss program. Once %BF is determined, a calculation can be completed to determine optimal body weight based on desired body fat level.  For example, a 20-year-old college male middle-distance runner had a BOD POD measurement of 11% body fat. He is 5’10’’ and weighs 160 pounds (BMI =23). Typically, college middle-distance runners have 6–9% BF. He and his sports dietitian determine that 8% body fat is a good goal for him based on his BMI and current percentage of body fat. His weight loss goal can be calculated using the following formulas:  FM = %BF x Body weight (lbs or kg) FFM = Body weight - FM Desired body weight = FFM ÷ (1- [Desired %BF])  Solution Of Example: Calculate FM: 0.11 x 160 = 17.6 Calculate FFM: 160 - 17.6 = 142.4 Desired Body Weight: 142.4 ÷ (1 - 0.08) = 154.8  This example shows that a modest weight loss of approximately 5 pounds (primarily fat loss) could be enough for this athlete to achieve a 3% drop in his body fat percentage and a reduction to a BMI of 22.  Once the goal weight and body composition are determined, athletes can consult with their sports dietitian to determine the energy intake that will produce this loss.  To lose weight, energy expenditure must be greater than energy intake. When exercise and activity are equal to energy intake, weight maintenance occurs.  If dietary intake is greater than energy expenditure, weight gain occurs.  To achieve negative energy balance for weight loss, athletes can decrease food intake, modify exercise and activity levels, or both, creating a total energy deficit.  The first step in estimating an athlete’s calorie needs is to use one of the equations listed in Table 11.5. This establishes an estimate of the athlete’s baseline energy expenditure and a starting point for determining the number of calories the athlete should reduce to produce weight loss.  Once this baseline is established, calorie intake recommendations should decrease this number by 250– 1000 calories per day.  This general guideline allows for a modest change in energy intake that will most likely not affect daily energy levels or the athlete’s ability to recover from workouts.  This large range of 250–1000 calories allows the athlete and the sports nutrition professional to have flexibility in calorie reduction levels based on the athlete’s weight, current dietary intake, and goal rate of weight loss. Athletes must be reminded not to dramatically decrease calorie intake because it can negatively affect sport performance.  The calorie recommendations for weight loss should always be compared to actual current intake and evaluated for necessary adjustments.  For example, an athlete’s total energy needs may be calculated at 3500 calories, which would translate into a weight loss recommendation of about 3000 calories per day. However, if the athlete is currently consuming 4000 calories, then suggesting a decrease in caloric intake merely to the originally calculated 3500 estimate may initiate some weight loss and appear less drastic to the athlete.  Combining a dietary reduction in calories with increased caloric expenditure is most likely to produce weight loss results for athletes.  Obtaining a daily deficit of 250–1000 calories by changing only diet or exercise by itself may be challenging.  Cutting calories too low often leads to hunger and discomfort. Most athletes cannot tolerate being hungry and thus have trouble adhering to the strict weight loss diet.  In addition, very low calorie diets can result in the body going into a protective mode, thus lowering basal metabolic rate making further weight loss and long-term weight management difficult.  Conversely, creating the calorie deficit solely from physical activity and exercise can lead to overtraining and injury.  A combination of a reduction of 250–500 dietary calories and a deficit of 250–500 calories produced from increased exercise and physical activity can produce a weight loss of approximately 1–2 pounds per week.  Dietary changes to reduce caloric intake are necessary for athletes to lose weight.  Athletes need to concentrate on matching the macronutrient intake recommended for weight loss to that required for continuing sport activities.  Portion control, regardless of macronutrient composition of the diet, is important in helping athletes reduce calories.  Eating regular meals to avoid becoming ravenous as well as proper meal planning also play an important role in any healthful weight reduction nutrition plan for athletes.  Macronutrient intake in athletes is of great importance in regard to sport performance. Carbohydrates, fat, and protein all perform essential functions within the body related to  overall health,  energy production, and  sport performance.  Therefore, when modifying an athlete’s total daily intake, consider the relative importance of the various macronutrients.  Carbohydrates are the primary macronutrient that athletes need to perform well in sport and exercise activities.  Carbohydrates are essential fuel for the working muscles during exercise and are valuable to muscles after exercise to replenish muscle glycogen stores.  Many popular diets recommend severe restriction in carbohydrates, including those foods that contain valuable nutrients (fruits, vegetables, whole grain breads, milk, and yogurt); these plans are recipes for performance disaster, often depleting an athlete’s body of carbohydrates as well as essential vitamins and minerals.  It can be beneficial to reduce some carbohydrates in the diet if the sources of carbohydrates do not provide nutritional value; for example, reducing foods that contain high amounts of added sugars (candy, cookies, soda, etc.) will reduce overall calories consumed without reducing the nutrient density in the athlete’s diet.  Substituting higher-fiber foods such as grains, fruits, and vegetables for some of these calorie-dense foods can increase feelings of fullness and satiety so that athletes may consume fewer calories throughout the day.  Protein is important in any athlete’s diet for maintaining muscle mass, building and repairing tissues, and providing satiety.  Consuming adequate amounts of protein to maintain these functions is critical, especially when athletes are making lifestyle changes for weight loss.  Maintenance of muscle mass can help keep the resting metabolic rate elevated, aiding in the weight loss effort and improving the likelihood of weight loss maintenance.  Athletes who consume at least the minimum amount of protein recommended for their sport activities should obtain enough protein to maintain protein’s necessary functions in the body.  Protein intakes at the high end of the recommended ranges may be appropriate for some athletes to produce better satiety levels. Athletes should be encouraged to choose lean, low fat protein sources that will contribute fewer total calories than high-fat options.  Fat is an essential component of a healthful athlete’s diet; however, intake should be moderated while trying to lose weight.  Fat contains more than twice the amount of calories per gram as carbohydrates or protein. Therefore, a reduction in fat can help produce a calorie deficit for weight loss because it is more calorie dense.  It should be emphasized that athletes are not encouraged to eliminate fat from the diet; a modest decrease in total fat intake to a level of approximately 20% of total calories will allow for the consumption of essential fatty acids without the contribution of excessive calories.  A weight loss plan that produces a reduction in calories, regardless of the macronutrient composition, should lead to weight loss.  For all athletes, the macronutrient composition of the reduced-calorie diet should match their individual needs to produce weight loss while maintaining quality sport performance.  Athletes should be educated on the detrimental effects of some popular diet plans that dramatically decrease or eliminate certain macronutrients, while encouraging the excessive intake of other macronutrients.  For athletes aiming to lose weight, balance, variety, and moderation should remain the mantras of healthy eating to ensure that all nutrient needs are being met