SPORTS NUTRITION

 

SPORTS NUTRITION

ATHLETES RELY ON THEIR NATURAL APPETITE AND SATIETY. THE APPROPRIATE TOTAL

 ENERGY INTAKE IS WHATEVER LEVEL MAINTAINS DESIRABLE AND HEALTHY WEIGHT.

  THE CALORIE INTAKE SHOULD BE BETWEEN 3000-6000 KCAL DEPENDING UPON THE ACTIVITY.

 IN PROPORTION TO THE CALORIE INTAKE , THE NEED FOR THIAMINE, RIBOFLAVIN AND NIACIN IS INCREASED.

CARBOHYDRATE -  IN EXERCISE MAJOR NUTRIENT FOR ENERGY SUPPORT IS CARBOHYDRATE.

THE BEST CONDITIONED ATHLETE OBTAINS ONLY 60-70 % OF THEIR NEEDS IN ENDURANCE

 EXERCISES FROM FAT. THE REST MUST COME FROM CARBOHYDRATE FROM BLOOD GLUCOSE

AND FROM LIVER AND MUSCLE GLYCOGEN. THE HIGHER THE INTENSITY OF EXERCISE,

THE MORE IMPORTANT IS GLYCOGEN USED AS FUEL. CARBOHYDRATE SHOULD CONTRIBUTE

ABOUT 55 % OR MORE OF THE DAILY CALORIE INTAKE.  COMPLEX CARBOHYDRATES ARE PREFERABLE

 AS THEY TAKE LONGER TO DIGEST, PROVIDE A MORE SUSTAINABLE  SOURCE OF BLOOD GLUCOSE

AND ARE METABOLISED PREFERENTIALLY INTO GLYCOGEN. SIMPLE SUGARS ARE LESS EFFICIENT TO

 MAINTAIN THE BODY’S GLYCOGEN STORES. THEY ARE MAINLY CONVERTED TO FATTY ACIDS STORED

 AS FAT RATHER THAN AS GLYCOGEN. SIMPLE CARBOHYDRATES  PROVOKE A SHARPER INSULIN

 RESPONSE, CONTRIBUTING TO THE DANGERS OF SUBSEQUENT HYPOGLYCEMIA. 

THE STORAGE OF CARBOHYDRATE IN LIVER AND MUSCLES DEPENDS UPON THE LEVEL OF ACTIVITY

 AND THE AMOUNT OF DIETARY CARBOHYDRATE.  MUSCLE RESYNTHESIS IS HIGHEST WHEN

 THE MUSCLE HAS BEEN DEPLETED. CARBOHYDRATE INGESTION  50 – 100 GRAMS SHOULD

BEGIN AFTER THE WORKOUT OR COMPETITION AS PRACTICAL 15-30 MINUTES AND CONTINUE

AT THE RATE OF 50 GRAMS  EVERY 2 HOURS UNTIL A LARGER MEAL OF SOLID FOOD 150-250 GRAMS IS DESIRED.

CARBOHYDRATE LOADING -  THE ABILITY TO SUSTAIN PEAK PERFORMANCE OVER

AN EXTENDED TIME PERIOD IS INFLUENCED BY THE AVAILABILITY OF MUSCLE GLYCOGEN.

 TO BUILD UP GLYCOGEN STORES TWO PHASES OF PREPARATION ARE RECOMMENDED.

FIRST ABOUT A WEEK ,  BEFORE COMPETITION THE ATHLETE EXERCISES VIGOROUSLY

 TO DEPLETE GLYCOGEN STORES AND CONSUMES DIET HIGH IN PROTEIN AND FAT

AND RESTRICTED TO ABOUT 100 GRAM CARBOHYDRATE . SECOND, AFTER 2 TO 3 DAYS

OF THE GLYCOGEN –DEPLETING PHASE, ADIET LOW IN FAT, MODERATE IN PROTEIN

ND HIGH IN CARBOHYDRATE 250-500 GRAMS IS CONSUMED FOR 3-4 DAYS.

COMPLEX CARBOHYDRATES WHICH PROVIDE VITAMINS AND MINERALS ARE PREFERRED

TO SIMPLE SUGARS. CARBOHYDRATE LOADING IS NOT RECOMMENDED FOR SHORT-TERM

 COMPETITION, AS IT CAN LEAD TO FEELING OF HEAVINESS. CARBOHYDRATE LOADING IS

 NOT RECOMMENDED FOR ATHLETES IN EARLY ADOLESCENCE AND SHOULD BE USED NO

 MORE THAN TWO OR THREE TIMES A YEAR BECAUSE MYOGLOBINURIA, CHEST PAIN,

 CHANGE IN ELECTROCARDIOGRAM  HAVE BEEN NOTICED. CARBOHYDRATE LOADING

 IS BASED ON THE PRINCIPLE OF DEPLETION-REPLETION. FOR ENDURANCE EVENTS

LASTING MORE THAN 90 MINUTES, CARBOHYDRATE LOADING MIGHT BE REQUIRED.

PROTEIN – PROTEIN INTAKE EQUAL TO 15-20% OF TOTAL CALORIES WILL MEET THE PROTEIN

 REQUIREMENTS OF MOST ATHLETES.  PRCONSUMING MORE PROTEIN THAN 2.0 G/KG BODY WEIGHT

RESULTS IN INCREASED PROTEIN OXIDATION, UREA FORMATION, DIURESIS AND

 CAN INCREASE RISK FOR DEHYDRATION. TYPE OF SPORT AND TOTAL CALORIE

 INTAKES INFLUENCE PROTEIN REQUIREMENTS.  HIGH PROTEIN DIETS INCREASE

 THE REQUIREMENT TO WATER INTAKE IN ORDER TO ELIMINATE NITROGEN THROUGH URINE.

 THUS, INCREASE IN METABOLIC RATE LEAD TO AN INCREASED OXYGEN CONSUMPTION.

INCREASED MUSCLE MASS CAN BE ACHIEVED BY LONG-TERM TRAINING. WITHOUT TRAINING,

 EXTRA DIETARY PROTEIN IS CONVERTED INTO FAT.  USE OF PROTEIN SUPPLEMENTS ARE NOT REQUIRED.

FAT -  IT IS IMPORTANT TO HAVE FAT IN THE DIET, ESSENTIAL FATTY ACIDS, LINOLENIC ACID.

 DIETARY FAT IS NOT NECESSARY TO MAINTAIN FAT STORES, SINCE EXTRA KILOCALORIES

 WILL BE STORED AS FATS.COMPULSIVE RUNNERS WHO ELIMINATE FAT FROM THEIR

DIET HAVE LINOLEIC ACID DEFICIENCY, AS A RESULT DEATH CAN OCCUR DUE TO CARDIAC ARREST.  

HIGH RATES OF FAT OXIDATION OCCURS DURING AEROBIC EXERCISE. AEROBIC EXERCISES

INCREASES THE ABILITY OF THE BODY TO USE FAT  AS AN ENERGY SOURCE. FREE FATTY ACIDS

ARE STORED WITH GLYCEROL AS TRIGLYCERIDES IN THE BODY’S ADIPOSE TISSUE. ENZYME

LIPOPROTEIN LIPASE MOBILIZES THESE STORES OF FATTY ACIDS. THIS LIPASE IS STIMULATED

 BY EXERCISE. ITS LEVEL IS INFLUENCED BY  LEVEL OF HORMONES, IMPLICATED IN EXERCISE,

 ESPECIALLY GROWTH HORMONE AND EPINEPHRINE. TOTAL ENERGY PROVIDED BY FAT

 RANGES FROM 20-30 % VISIBLE AND INVISIBLE WITH THE RATIO OF 2:1.

VITAMINS AND MINERALS – WITH THE EXCEPTION OF RIBOFLAVIN, INCREASED EXERCISE

 LEVELS ARE NOT CORRELATED WITH INCREASED DIETARY NEEDS FOR VITAMINS OR MINERALS.

THERE IS AN INCREASED RISK OF STRESS FRACTURE WHICH IS ASSOCIATED WITH LOWER CALCIUM

INTAKE AND LOW BONE DENSITY. THE CALCIUM INTAKE OF 1-2 GRAMS PER DAY IS RECOMMENDED. 

ADEQUATE AMOUNTS OF IRON IS ESSENTIAL FOR AN OPTIMAL AEROBIC ENDURANCE PERFORMANCE.

IRON INTAKE SHOULD NOT BE LESS THAN 50-75 MG FOR SPORTS  MAN AND 60-100 MG FOR A SPORTS WOMAN.

IT  IS ADVISABLE TO EAT NUTRIENT-DENSE MEALS THAT WILL MAINTAIN ENERGY.ZINC IS NEEDED

FOR PROTEIN SYSNTHESIS. SUPPLEMENTATION IS NOT A REPLACEMENT OF FOOD.

DEHYDRATION – IT IS A SERIOUS PROBLEM AMONGST ATHLETES . THEY MUST OBTAIN 90% OF THEIR

WATER INTAKE BY DRINKING WATER. GROUPS MOST VULNERABLE TO DEHYDRATION ARE MARATHON

RUNNERS AND WRESTLERS. SMALL CUPS OF COLD WATER SHOULD BE DRUNK EVERY 15 MINUTES

DURING ATHLETIC EVENTS OF LONG DURATION. WHEN FLUID LOSS IN EXCESS OF 4 LITRES PER HOUR

ARE ANTICIPATED, THE TEAM PHYSICIAN MIGHT RECOMMEND SOME ELECTROLYTE REPLACEMENT .

 

PRE EVENT MEALS – IT SHOULD BE HIGH IN CARBOHYDRATES AND READILY-DIGESTED.

FOUR HOURS BEFORE, THE ATHLETE SHOULD CONSUME 4 GRAMS OF CARBOHYDRATES/KG BODY WEIGHT,

WHEREAS 1 HOUR BEFORE THE COMPETITION THE ATHLETE WOULD CONSUME 1 GRAM OF

 CARBOHYDRATE/KG BODY WEIGHT. PRECOMPETITION MEAL SHOULD BE TAKEN 1 TO 4 HOURS

 BEFORE COMPETING IT SHOULD PROVIDE 300-1000KCAL, SHOULD BE LOW IN FAT, HIGH IN COMPLEX CARBOHYDRATES.

DURING THE EVENT – DRINK ONLY FLUIDS. IF THE EVENT IS ALL DAY, HIGH CARBOHYDRATE , LOW FAT FOODS ARE TAKEN.

AFTER THE EVENT -  TAKE PLENTY OF CARBOHYDRATES, LOTS OF FLUIDS, JUICES, EASILY DIGESTIBLE.

COFFEE, TEA,  CAFFEINE, BEER SHOULD BE AVOIDED.