Athlete Nutrition KIN 334 Notes PDF

Athlete Nutrition CHO Intake Liver Vs. Muscle Glycogen Muscle glycogen has 12-16g of CHO per Liver glycogen can be released to kg of muscle the whole body, including t...

Athlete Nutrition CHO Intake Liver Vs. Muscle Glycogen Muscle glycogen has 12-16g of CHO per Liver glycogen can be released to kg of muscle the whole body, including the CNS High intensity exercise Liver glycogen has a higher concentration depletes liver glycogen by 50% than muscle glycogen, but has a lesser absolute amount Muscle Glycogen is mostly used for muscular contractions Time to exhaustion is directly Liver glycogen can be depleted overnight(under 20g) related to resting glycogen stores Effect of training the endurance system: Glycogen sparring due to enhanced lipid oxidation Larger glycogen stores in Glycemic Index(GI) muscle How well CHO can be absorbed Affected by: The biomechnical structure of the molecule The absorption process The size of the particle What it is co-ingested with Gold standard is pure glucose which has a GI of 100  High GI does not equal healthy food Why a high or low GI diet would be beneficial CHO Reccomendations around competition Days leading into competition: The goal is to replenish muscle glycogen to maximize stores (Supercompensation) Muscle glycogen will Supercompensation: supercompensate before liver glycogen, can add different sources Can increase pre-event glycogen by 50% of CHO for more stores(fructose + Can increase time to fatigue glucose) Can decrease time to complete event Generally for events longer than 60-90 min Negative implications: Have to consider if the extra water weight that comes with the glycogen stores is worth it Not always feasible to load for 5-7 days Type of loading: Classical - "Starve the muscle" 7-5 days out - Drastically increase intake 3 days out Modern Women tend to have a - Graducally increase intake greater reliance on fat each day oxidation, meaning supercompensation might not be as effective Negative Implications If CHO is lowered, hypoglycemia can occur GI issues with higher CHO intake Hours leading into competition: The goal is to increase glucose delivery to the muscle Has a more direct impact on performance General reccomendation is 200-300g of CHO 3-4 hours before exercise Always want to test out pre-competition CHO beforehand As you get closer you should start to consider high GI meals and less volume of food CHO Intake During Competition In events where fatigue develops due to lack of glucose/glycogen, performance can be improved by adding CHO during competition It is better to take smaller amounts of CHO every 15-20 min Not high fructose, want higher GI If glycogen stores are "full", adding fructose can increase the preservation of glycogen 0.7g/kg/hr 30-60g/hr up to 90 CHO Intake After Competition Goal is to replenish muscle and liver glycogen quickly and to create an enviroment that is beneficial to glycogen repletion Moderate to high GI foods within 30 min post exercise 1.0-1.2g/kg/hr Quicker phase of glycogen synthesis: Eating immediately after Slower phase of glycogen synthesis: Insulin mediated in the hours following Eat sufficient CHO within 6 hours post competition, glycogen stores will replenish between 8 and 24 hours post exercise  What effect does endurance FAT Intake training have on fat metabolism? Improved ability to oxidize FFA Increasing fat intake can be more Increased amount of enzymes beneficial to performance when trying to that can oxidize fats make weight. Glycogen stores water and Eaiser transportation of FFA will then be depleted when weight is cut through plasma membrae In theory, higher fat intake could increase the ability to oxidize FFA and spare muscle glycogen Experimental Evidence: Longer endurance sessions with a lower CHO availability can be better performed with higher fat intake Not the case with high-intensity exercise As intensity of session decreases, there are some advantages shown with higher fat As intensity of session increases, high CHO diets are more favourable New Approaches to Fat Intake Periodization of intake: If you train with lower glycogen levels, you will utilize fats more efficiently, leading to better preservation of glycogen during performance Twice per day training: If you train twice in one day, the second session will be in a depleted state  PRO Intake Gluconeogenisis- The conversion of protein to glucose Amino Acids: 9 essential, 11 non-essential Complete proteins contain all 9 essential amino acids Protein requirements for athletes: Protein synthesis must be increased to repair damage done General Guidelines: 0.8g/kg/day Anywhere from 10-35% of TDEE Athlete Guidelines 1.2-2.0g/kg/day Other Ways to Increase Protein Synthesis(Other Than Eating More PRO) Co-Ingestion with CHO Eating smaller amounts of protein more frequently Timing of protein(Pre/post training) Different types of protein  Supplements and Ergogenic Aids Ergogenic Aid - Substances or techniques used to improve athletic performance Supplements - A food or non-food product that is used intentionally with the goal of a specific benefit Categories of supplements: Reasons to use supplements: Sports foods Correct or prevent nutrient Medical Supplements deficiencies Performance Supplement Convinience Direct benefits for competition "Just in case" Caffeine Ephedrine Stimulates the SNS Stimulates the SNS What are they? Half life of 2-10 hours Used over the counter as Peaks in blood 1 hour after ingestion pseudoephedrine(Less effective) Metabolized in the liver Relaxes smooth muscles(Theophylline) Increases energy What affect do Reduces the negative feedback that inhibits expenditure(Thermogenic) they have? secretion of noradrenaline Decreases hunger(Appetite Increases mental awareness and fiber suppressant) recruitment Stimulate a and b Increases lipolysis(Paraxanthine) receptors(Sympathomimetic) Dialates blood vessels(Theobromine) Studies Short term effect of increasing resting Significant improvements in weight oxygen consumption loss were shown Long term effect of almost no change Lots of adverse effects were also compared to placebo shown Prevents a drop in RMR when calories are restricted Side Effects Increase HR More consistent adverse effects Small diuretic effect Tremors Iron deficiency Increase HR and BP Insulin resistance  Caffeine alone does not show much effect Ephedrine alone shows some effect of about 0.5kg/month of loss Caffeine + Ephedrine shows an increased effect of 1.0kg/month Caffeine slows the reuptake of ephedrine, which increases its effect Creatine What are they? Used to shuttle intracellular energy from the mitochondria to the cytosol(ATP-PCr reaction) 1-2 g found in skeletal muscle(1-2% is excreted as urine), 1g from daily endogenous production, 1g from diet What affect do Increases muscle glycogen they have? Anaerobic alactic energy source Promotes muscle growth Studies Shown that creatine uptake by muscles increase when taken with CHO Those with lowest creatine levels are shown to have greater improvements following supplementation Side Effects Extreme use can make creatine less effective Females have higher intramuscular stores, less responsive Water/weight gain is shown Produced from a lab, not from animals, less micronutrients 95% of creatine is found in skeletal muscle (main dietary source is meat)  Relative Energy Deficiency in Sports(REDs) When in negative energy balance for consistent periods of time, athletes will start to show signs of REDs As of 2023: Acknowledged the REDs- A syndrome of physiological and prevalence of REDs in psychological functioning caused by exposure men to consistent low energy availability, leading to Its not just about energy decreased erformance and impaired well availability, but being specifically CHO availability Can lead to disordered eating Acknowledged the connection between REDs and mental health Disordered Eating- A continuum from healthy eating to unhealthy eating. A balance between eating and exercise Low Energy Availability Effects 62% of Feamale athletes and 33% Cutoff of 30-45 kcal/kg of FFM/day of Male athletes Estimated prevalence: 23-80% Can include clinical disorders (Female), 15-70%(Male) Eating Disorders Anorexia Nervosa Restriction of energy intake leading to a significantly low body weight There is an intense fear of gaining weight Denial of the seriousness of low body weight Bulimia Nervosa Recurrent episodes of binge eating Recurrent compensatory behaviour to avoid weight gain Both occurring at least once a week for 3 months  Menstrual dysfunction Menarche - A womans first menstrual cycle Primary: The absence comes before menarche Eumenorrhea - The "normal" menstrual cycle Roughly 7% overall Amenorrhea - The absence of a menstrual cycle Oligomenorrhea - Longer than normal menstrual cycle Secondary: The absence comes Anovulation - A menstrual cycle without ovulation after menarche 2-5% overall Luteal Suppression - Luteal phase is shorter than 11 days Insufficient energy availabiliy is shown to lead to menstrual dysfunction Low Energy Availability in Males Only 20% of current research is in men Cutoff for LEA is lower than 30kcal/kgFFM/day, or 30 for longer periods of time Symptoms: Low testosterone ED Decreased libido Sperm abnormalities Low Bone Mineral Density Caused by: Low BMD is a z score inbetween -1 and -2 Low calcium intake High cortisol Osteoperosis is more severe with a z Low IGF-1 score on less than -2 Undernutrition(decreased rate of bone formation) Hypernutrition(Increased bone reabsorption rate)