Nutritional Factors Influencing Body Composition.

Nutritional FactorsNutritional Factors

Influencing Body Influencing Body CompositionComposition

OverconsumptionOverconsumption

• The government recommends 1600 The government recommends 1600 calories a day for the average calories a day for the average sedentary woman and 2200 for men. sedentary woman and 2200 for men.

• In 2000, our reported per capita In 2000, our reported per capita daily caloric consumption was 1877 daily caloric consumption was 1877 for women and 2618 for men.for women and 2618 for men.

Nutrition and Nutrition and ExerciseExercise

Where do we get the energy for Where do we get the energy for movement?movement?

What should we eat to insure What should we eat to insure optimal health and fitness?optimal health and fitness?

Nutrition and ExerciseNutrition and Exercise

• Energy for movement comes from Energy for movement comes from the food we eat.the food we eat.

• The three sources of energy are:The three sources of energy are:– CarbohydratesCarbohydrates– FatsFats– ProteinsProteins


General Recommendations:General Recommendations:• CHOCHO 55-65%55-65%

– CNSCNS– Primary fuel sourcePrimary fuel source– Only anaerobic fuel sourceOnly anaerobic fuel source– Required for fat metabolismRequired for fat metabolism– Required for protein metabolismRequired for protein metabolism

Nutrition and ExerciseNutrition and Exercise• FatFat 20-30%20-30%

– Major fuel source for endurance activityMajor fuel source for endurance activity– Essential component of cell membranes Essential component of cell membranes

and nerve fibersand nerve fibers– InsulationInsulation– Shock absorptionShock absorption– Hormone productionHormone production– Fat soluble vitaminsFat soluble vitamins


• FatFat– High in kcal per weightHigh in kcal per weight– Low fat = <20%Low fat = <20%– Read labels - for something to be low Read labels - for something to be low

fat, there should be no more than fat, there should be no more than 1 1 gram of fat for every 50 kcals.gram of fat for every 50 kcals.

– 100 kcals : 2 g fat = 18% fat (9 kcals 100 kcals : 2 g fat = 18% fat (9 kcals per gram of fat)per gram of fat)


• ProteinProtein 10-15%10-15%– Growth and maintenance of lean tissueGrowth and maintenance of lean tissue– Repair of damaged tissueRepair of damaged tissue– Fuel source during starvationFuel source during starvation

Old Food Guide PyramidOld Food Guide Pyramid

Food Guide PyramidFood Guide Pyramid

• Key Points (2004):Key Points (2004):– At least 3 one-ounce servings of whole grains each At least 3 one-ounce servings of whole grains each

day (instead of refined sugars and white bread)day (instead of refined sugars and white bread)

– Whole grains contain more fiber which has been Whole grains contain more fiber which has been shown to reduce the risk of heart disease and shown to reduce the risk of heart disease and diabetesdiabetes

– Increase daily intake of fruits and vegetables, Increase daily intake of fruits and vegetables, whole grains, and nonfat or low fat milk and milk whole grains, and nonfat or low fat milk and milk productsproducts

Food Guide PyramidFood Guide Pyramid

www.mypyramid.gov

NutrientsNutrients

• CHOCHO• FatFat• ProteinProtein• WaterWater• VitaminsVitamins• MineralsMinerals

VitaminsVitamins

• Fat SolubleFat Soluble– A D E KA D E K

• Water SolubleWater Soluble– B ComplexB Complex– CC

Free Radicals and Free Radicals and AntioxidantsAntioxidants

• Free-radical generation increases Free-radical generation increases after acute exercise and potentially after acute exercise and potentially causes oxidative tissue damage.causes oxidative tissue damage.

• May lead to cancer.May lead to cancer.• Consuming antioxidants (e.g., Consuming antioxidants (e.g.,

vitamin E and vitamin E and ββ-carotene) can trap -carotene) can trap free radicals and prevent this action.free radicals and prevent this action.

MineralsMinerals

• CalciumCalcium• PhosphorusPhosphorus• MagnesiumMagnesium• IronIron• PotassiumPotassium• SodiumSodium

CalciumCalcium

• RDA for most adults = 1000 mgRDA for most adults = 1000 mg– For teenagers = 1300 mgFor teenagers = 1300 mg– For those over 50 = 1200 mgFor those over 50 = 1200 mg– Highest food sources are dairy and Highest food sources are dairy and

calcium-fortified orange juice.calcium-fortified orange juice.

IronIron

• RDA = 8 mg for men and RDA = 8 mg for men and postmenopausal womenpostmenopausal women

• 18 mg for pre-menopausal women18 mg for pre-menopausal women• 27 mg for pregnant women27 mg for pregnant women

– Upper limit = 45 mg or stomach Upper limit = 45 mg or stomach upset can occur.upset can occur.

ZincZinc

• RDA = 11 mg for men, 8 for womenRDA = 11 mg for men, 8 for women• Upper limit = 40 mgUpper limit = 40 mg• More can block absorption of More can block absorption of

another vital nutrient, copper.another vital nutrient, copper.

WaterWater

• Important before, during, and after Important before, during, and after physical activity.physical activity.

• 2.5 liters per day.2.5 liters per day.• Major factor limiting exercise Major factor limiting exercise

performance.performance.• Thirst.Thirst.

DietingDieting

• Starvation diets will cause weight loss.Starvation diets will cause weight loss.

• However, they also cause physiologic However, they also cause physiologic dysfunction and potentially death.dysfunction and potentially death.

• In addition to fat loss, you lose muscle In addition to fat loss, you lose muscle mass, bone mass, and water volume.mass, bone mass, and water volume.

Yo-Yo DietingYo-Yo Dieting

• The more you diet, the fatter you become.The more you diet, the fatter you become.

• When you lose, you lose muscle, fat, When you lose, you lose muscle, fat, water, and bone.water, and bone.

• When you return to your normal lifestyle, When you return to your normal lifestyle, you add on fat and water, but unless you you add on fat and water, but unless you increase activity levels drastically, you increase activity levels drastically, you don’t add bone or muscle mass.don’t add bone or muscle mass.

Fad DietsFad Diets

• Why are they so popular?Why are they so popular?

• They give the false impression that you They give the false impression that you can eat what you like, in the quantities can eat what you like, in the quantities that you want, without having to that you want, without having to exercise, and still lose weight.exercise, and still lose weight.

• Very seductive message.Very seductive message.

Low CarbLow Carb

• Hype:Hype:– Carbs are not healthyCarbs are not healthy– Carbs negatively impact blood sugar Carbs negatively impact blood sugar

levels through high glycemic index levels through high glycemic index raising insulin levelsraising insulin levels

– Low blood sugar leads to hungerLow blood sugar leads to hunger– Invented concept of “Net Carbs”Invented concept of “Net Carbs”

Low CarbLow Carb

• Facts:Facts:– Low blood sugar hasn't been directly Low blood sugar hasn't been directly

linked to hunger.linked to hunger.– Unless you have diabetes, blood sugar Unless you have diabetes, blood sugar

remains generally stable anyway.remains generally stable anyway.– When you stop eating carbohydrates, When you stop eating carbohydrates,

your brain stops regulating serotonin, a your brain stops regulating serotonin, a chemical that elevates mood and chemical that elevates mood and suppresses appetite.suppresses appetite.

Low CarbLow Carb

• Facts:Facts:– Only carbohydrate consumption naturally Only carbohydrate consumption naturally

stimulates production of serotonin.stimulates production of serotonin.– When serotonin is made and becomes When serotonin is made and becomes

active in your brain, its effect on your active in your brain, its effect on your appetite is to make you feel full before appetite is to make you feel full before your stomach is stuffed and stretched.your stomach is stuffed and stretched.

– The brain makes serotonin only after a The brain makes serotonin only after a person consumes sweet or starchy person consumes sweet or starchy carbohydrates.carbohydrates.

Low CarbLow Carb

• Facts:Facts:– The kicker is that these carbohydrates The kicker is that these carbohydrates

must be eaten in combination with very must be eaten in combination with very little or no protein.little or no protein.

– This can explain why people may still This can explain why people may still feel hungry even after they have eaten a feel hungry even after they have eaten a 20-ounce steak. 20-ounce steak.

– Their stomachs are full but their brains Their stomachs are full but their brains may not be making enough serotonin to may not be making enough serotonin to shut off their appetites.shut off their appetites.

Low CarbLow Carb

• August 1August 1stst, 2005 Atkins Nutritionals , 2005 Atkins Nutritionals declares bankruptcydeclares bankruptcy

Body Composition Body Composition QuestionsQuestions

• Why do low-carbohydrate diets Why do low-carbohydrate diets produce such a rapid weight loss?produce such a rapid weight loss?

• Diets that limit or totally exclude Diets that limit or totally exclude CHO produce a rapid weight loss.CHO produce a rapid weight loss.

• When CHO intake is low, muscle When CHO intake is low, muscle glycogen stores are depleted rapidly.glycogen stores are depleted rapidly.


• For every gram of CHO, 3 grams of For every gram of CHO, 3 grams of HH220 are stored in the body.0 are stored in the body.

• When glycogen stores are depleted, When glycogen stores are depleted, the loss of water leads to a dramatic the loss of water leads to a dramatic weight loss because each liter of weight loss because each liter of water weighs approximately 2 lbs.water weighs approximately 2 lbs.


• The weight is regained rapidly, The weight is regained rapidly, however, when CHO intake returns however, when CHO intake returns to normal.to normal.

Protein PowerProtein Power

• 850-1,100 kcal/d850-1,100 kcal/d• High proteinHigh protein

The ZoneThe Zone

• 1,300 kcal/d for women and 1,700 kcal/d 1,300 kcal/d for women and 1,700 kcal/d for menfor men

• Follow the 40-30-30 ruleFollow the 40-30-30 rule• No foods are off limits, but they claim No foods are off limits, but they claim

some foods are better than otherssome foods are better than others– Example – broccoli, celery, and grapes = goodExample – broccoli, celery, and grapes = good– Cereal, bagels, and bananas = badCereal, bagels, and bananas = bad

• No real justification for these No real justification for these classificationsclassifications

Sugar Busters!Sugar Busters!

• 1,200 kcal/d with 28% of total 1,200 kcal/d with 28% of total energy intake from fatenergy intake from fat

• 33% of total energy intake from 33% of total energy intake from proteinprotein

South Beach DietSouth Beach Diet

• Steer clear of bread and beer Steer clear of bread and beer (maltose)(maltose)

• No fruit, bread, sugary snacks, No fruit, bread, sugary snacks, potatoes, pasta, or ricepotatoes, pasta, or rice

• No scientific support for these No scientific support for these recommendations, but at least allows recommendations, but at least allows whole grains, some fruit (later), and whole grains, some fruit (later), and cuts back on saturated fatcuts back on saturated fat

Nutrition QuestionsNutrition Questions

• Why are low carbohydrate diets Why are low carbohydrate diets unsafe?unsafe?

• Low CHO intake may lead to fatigue, Low CHO intake may lead to fatigue, hypoglycemia, and ketosis.hypoglycemia, and ketosis.


• Low carb diets are detrimental to Low carb diets are detrimental to anaerobic work capacity because of anaerobic work capacity because of reduced muscle glycogen stores and reduced muscle glycogen stores and decreased rate of glycolysis.decreased rate of glycolysis.


• Many of the fad diets (Atkins Diet Many of the fad diets (Atkins Diet Revolution, Sugar busters, the Zone) Revolution, Sugar busters, the Zone) result in weight reduction primarily result in weight reduction primarily because they are low calorie diets.because they are low calorie diets.


• Low carb diets are high in fat, Low carb diets are high in fat, saturated fat, and cholesterol.saturated fat, and cholesterol.


• The nature of low carb diets is a diet The nature of low carb diets is a diet low in fruits, vegetables, grains, and low in fruits, vegetables, grains, and beans.beans.

• These foods are all high in health These foods are all high in health promoting and disease preventing promoting and disease preventing properties.properties.


• Do we need to consume large Do we need to consume large amounts of protein if we exercise amounts of protein if we exercise and wish to increase muscle mass?and wish to increase muscle mass?


Recommended Levels of Protein Recommended Levels of Protein ConsumptionConsumption

RDARDA SedentarySedentary EnduranceEndurance StrengthStrength

g/kg/dayg/kg/day 0.8 0.8 1.2 - 1.4 1.2 - 1.4 1.4 - 1.4 - 2.02.0


• ““No valid evidence exists supporting No valid evidence exists supporting the notion that protein intake the notion that protein intake exceeding 1.8 - 2.0 will provide exceeding 1.8 - 2.0 will provide additional advantage”additional advantage”– International Journal of Sports International Journal of Sports

NutritionNutrition


• ““The recommended levels may be The recommended levels may be reached within the total protein reached within the total protein percentage recommendations of 10-percentage recommendations of 10-15% of all calories consumed daily”15% of all calories consumed daily”

• International Journal of Sports International Journal of Sports NutritionNutrition


• ExampleExample– 220 lbs male = 100 kg220 lbs male = 100 kg– excessive intake = 2.0 (g/kg/day)excessive intake = 2.0 (g/kg/day)– daily need = 200 gramsdaily need = 200 grams– typical consumption = 6000 kcalstypical consumption = 6000 kcals

10-15% of 6000 kcal = 600 -900 kcal of 10-15% of 6000 kcal = 600 -900 kcal of proteinprotein

– divided by 4 kcals per gram divided by 4 kcals per gram – 150-250 grams of protein.150-250 grams of protein.

Amino Acids and ProteinAmino Acids and Protein

• In all but a few exceptional cases, In all but a few exceptional cases, the maximal contribution of protein the maximal contribution of protein as an energy source during exercise as an energy source during exercise ranges between 2% and 10% of the ranges between 2% and 10% of the total energy expended.total energy expended.– (Gibala; Hargreaves, and Tipton, 2000)(Gibala; Hargreaves, and Tipton, 2000)


• In theory, amino acids could In theory, amino acids could contribute to carbohydrate contribute to carbohydrate metabolism during exercise, but metabolism during exercise, but there is no hard evidence that this there is no hard evidence that this occurs or has any bearing on sport occurs or has any bearing on sport performance.performance.– (Gibala; Hargreaves, and Tipton, 2000)(Gibala; Hargreaves, and Tipton, 2000)


• Supplementation of the athlete’s diet Supplementation of the athlete’s diet with branched-chain amino acids with branched-chain amino acids apparently does not benefit exercise apparently does not benefit exercise performance.performance.– (Gibala; Hargreaves, and Tipton, 2000)(Gibala; Hargreaves, and Tipton, 2000)


• The most important factors for The most important factors for optimizing growth when one optimizing growth when one performs resistance exercise are:performs resistance exercise are:

• Adequate resistanceAdequate resistance• Adequate caloric consumption, Adequate caloric consumption,

including just after liftingincluding just after lifting• Plenty of rest between sessionsPlenty of rest between sessions

– (Gibala; Hargreaves, and Tipton, 2000)(Gibala; Hargreaves, and Tipton, 2000)


• With rare exceptions athletes With rare exceptions athletes require 1.2 – 1.6 grams of protein require 1.2 – 1.6 grams of protein per kg day.per kg day.

• This amount of protein can almost This amount of protein can almost always be obtained in the normal always be obtained in the normal diet.diet.– (Gibala; Hargreaves, and Tipton, 2000)(Gibala; Hargreaves, and Tipton, 2000)


• There is no solid evidence that There is no solid evidence that special mixtures of amino acids special mixtures of amino acids provide any advantage over normal provide any advantage over normal dietary proteins in stimulating dietary proteins in stimulating muscle growth.muscle growth.– (Gibala; Hargreaves, and Tipton, 2000)(Gibala; Hargreaves, and Tipton, 2000)


• Are high-protein diets safe?Are high-protein diets safe?• High-protein diets that limit CHO High-protein diets that limit CHO

intake promote muscle tissue loss.intake promote muscle tissue loss.• When CHO intake is restricted, the When CHO intake is restricted, the

glucose needs of the body are met glucose needs of the body are met by breaking down proteins.by breaking down proteins.


• Excessive protein intake does not Excessive protein intake does not promote protein synthesis.promote protein synthesis.

• Instead the excess protein is Instead the excess protein is metabolized.metabolized.


• The amino acids are deaminated, the The amino acids are deaminated, the excess nitrogen is excreted in the excess nitrogen is excreted in the urine as urea, and the remaining urine as urea, and the remaining carbon skeleton is converted to carbon skeleton is converted to glucose or used as an energy fuel.glucose or used as an energy fuel.


• Some high-protein diets require Some high-protein diets require drinking large quantities of water to drinking large quantities of water to prevent the dehydration caused by prevent the dehydration caused by excess urea production and to wash excess urea production and to wash away ketone bodies. away ketone bodies.


• Dehydration and the additional Dehydration and the additional stress placed on the kidneys may be stress placed on the kidneys may be potentially dangerous, especially for potentially dangerous, especially for individuals with kidney problems or individuals with kidney problems or gout.gout.


• Protein intake above 2.8 g/kg/d has Protein intake above 2.8 g/kg/d has been shown to impair renal function.been shown to impair renal function.

• High-protein diets may promote High-protein diets may promote urinary calcium loss which is urinary calcium loss which is particularly a concern for women particularly a concern for women bodybuilders. bodybuilders.


• Are high-fat diets unsafe?Are high-fat diets unsafe?• YesYes• They produce high levels of serum They produce high levels of serum

cholesterol and triglycerides which cholesterol and triglycerides which may lead to atherosclerosis.may lead to atherosclerosis.


• Typically high-fat diets are high in Typically high-fat diets are high in calories, therefore a smaller volume calories, therefore a smaller volume of food must be consumed.of food must be consumed.

• There are no metabolic pathways in There are no metabolic pathways in the body for converting fatty acids to the body for converting fatty acids to glucose, so excess fat is stored in glucose, so excess fat is stored in adipose tissue.adipose tissue.


• What is the danger of fasting or What is the danger of fasting or skipping meals to promote weight skipping meals to promote weight loss?loss?

• Potential side effects include kidney Potential side effects include kidney malfunction, hyperuricemia, loss of malfunction, hyperuricemia, loss of hair, dizziness, fainting, and muscle hair, dizziness, fainting, and muscle cramping.cramping.


• When the body is deprived of food, it When the body is deprived of food, it responds by increasing the fat-responds by increasing the fat-depositing enzymes and storing depositing enzymes and storing more fat.more fat.

• The body will also metabolize The body will also metabolize protein to meet its energy needs.protein to meet its energy needs.

• Body will absorb more of the food Body will absorb more of the food that appears in digestive system.that appears in digestive system.


• Why should a fat loss diet include at Why should a fat loss diet include at least 55-65% carbohydrates?least 55-65% carbohydrates?

• CHO helps maintain normal function CHO helps maintain normal function of the nervous system because nerve of the nervous system because nerve tissue relies solely on glucose as a tissue relies solely on glucose as a fuel for energy.fuel for energy.


• Consuming adequate amounts of Consuming adequate amounts of CHO on a daily basis prevents the CHO on a daily basis prevents the depletion of glycogen stores and the depletion of glycogen stores and the need to synthesize glucose from the need to synthesize glucose from the body’s protein (protein-sparing body’s protein (protein-sparing effect).effect).


• When glycogen stores are depleted, When glycogen stores are depleted, the glucose needs of the body are the glucose needs of the body are met through the breakdown of met through the breakdown of muscle protein.muscle protein.

• This leads to a loss of lean tissue This leads to a loss of lean tissue rather than fat.rather than fat.


• CHO is also essential for fat CHO is also essential for fat metabolism.metabolism.

• When CHOs are restricted or CHO When CHOs are restricted or CHO stores are depleted, more fatty acids stores are depleted, more fatty acids are mobilized from adipose tissue are mobilized from adipose tissue that can be metabolized by the body.that can be metabolized by the body.


• This results in the incomplete This results in the incomplete breakdown of lipids and the breakdown of lipids and the formation of ketone bodies that may formation of ketone bodies that may cause ketosis.cause ketosis.


• In addition, muscle glycogen and In addition, muscle glycogen and glucose are the primary fuels used glucose are the primary fuels used during intense, short-term exercise during intense, short-term exercise and prolonged, submaximal and prolonged, submaximal exercise.exercise.


• Inclusion of adequate amounts of Inclusion of adequate amounts of CHO in the diet prevents depletion CHO in the diet prevents depletion of muscle glycogen and the of muscle glycogen and the consequent reduction in endurance consequent reduction in endurance performance.performance.

Sugared DrinksSugared Drinks

• High levels of intake of sugar-High levels of intake of sugar-sweetened drinks and of fruit juice sweetened drinks and of fruit juice raise weight over time in educated raise weight over time in educated women in their 30s (Schulze, 2004)women in their 30s (Schulze, 2004)

• Higher intake of diet soft drinks Higher intake of diet soft drinks reduces weight gainreduces weight gain


• Higher take of sugar-sweetened Higher take of sugar-sweetened drinks raise the risk for type 2 drinks raise the risk for type 2 diabetes in women without a family diabetes in women without a family history of diabetes.history of diabetes.

• Does not appear true for fruit juiceDoes not appear true for fruit juice


• Low levels of sugar-sweetened drink Low levels of sugar-sweetened drink intake does not increases weight intake does not increases weight gain or diabetes over time.gain or diabetes over time.

Athletes and NutritionAthletes and Nutrition

• Swimmer Michael Phelps’s next career may be in Swimmer Michael Phelps’s next career may be in competitive eating. competitive eating.

• Besides grabbing five gold medals at the Beijing Besides grabbing five gold medals at the Beijing Olympics so far, making him the winningest Olympics so far, making him the winningest Olympic athlete ever, he’s got to be setting new Olympic athlete ever, he’s got to be setting new marks on the chow line.marks on the chow line.

• A New York Post account of Phelps’s… wait for A New York Post account of Phelps’s… wait for it… 12,000-calorie-a-day diet, gave us a it… 12,000-calorie-a-day diet, gave us a stomachache. stomachache.


• Could one human being really Could one human being really consume that much and still be in consume that much and still be in Phelps’s shape? Phelps’s shape?

• And could this possibly be healthy And could this possibly be healthy for Phelps, even considering his five-for Phelps, even considering his five-hours-a-day, six-days-a-week hours-a-day, six-days-a-week exercise regimen?exercise regimen?


• Here’s Phelps’s typical menu. Here’s Phelps’s typical menu.

• No, he doesn’t choose No, he doesn’t choose amongamong these options. these options.

• He eats them He eats them allall, according to the Post., according to the Post.

• Breakfast:Breakfast: Three fried-egg sandwiches loaded with Three fried-egg sandwiches loaded with cheese, lettuce, tomatoes, fried onions and cheese, lettuce, tomatoes, fried onions and mayonnaise. Two cups of coffee. One five-egg omelet. mayonnaise. Two cups of coffee. One five-egg omelet. One bowl of grits. Three slices of French toast One bowl of grits. Three slices of French toast topped with powdered sugar. Three chocolate-chip topped with powdered sugar. Three chocolate-chip pancakes.pancakes.


• Lunch:Lunch: One pound of enriched One pound of enriched pasta. Two large ham and cheese pasta. Two large ham and cheese sandwiches with mayo on white sandwiches with mayo on white bread. Energy drinks packing 1,000 bread. Energy drinks packing 1,000 calories. calories.

• Dinner:Dinner: One pound of pasta. An One pound of pasta. An entire pizza. More energy drinks. entire pizza. More energy drinks.


• Does a diet like this make sense even for a Does a diet like this make sense even for a calorie-incinerating human swimming machine? calorie-incinerating human swimming machine?

• If you eat fewer calories than you burn If you eat fewer calories than you burn exercising, you lose weight. exercising, you lose weight.


• But an athlete like Phelps, who But an athlete like Phelps, who exercises up a storm, has to worry exercises up a storm, has to worry about eating about eating enoughenough to replenish the to replenish the scads of calories he’s burned. scads of calories he’s burned.

• If he doesn’t, his “body won’t recover, If he doesn’t, his “body won’t recover, the muscles will not recover, there the muscles will not recover, there will not be adequate energy stored for will not be adequate energy stored for him to compete in his next event.”him to compete in his next event.”


• But what about the choice of foods? But what about the choice of foods?

• All those eggs and ham and cheese can’t possibly All those eggs and ham and cheese can’t possibly be good for him, can they? be good for him, can they?


• Says Klion, “I think for him, because of his Says Klion, “I think for him, because of his caloric demands, he can probably eat whatever caloric demands, he can probably eat whatever he wants to.” he wants to.”

• And besides, Klion says, if you’ve got to eat that And besides, Klion says, if you’ve got to eat that much, it better be enjoyable, or you won’t be much, it better be enjoyable, or you won’t be able to keep up. able to keep up.

• Phelps might not be so eager to shovel down a Phelps might not be so eager to shovel down a pound of tofu in a sitting, Klion points out.pound of tofu in a sitting, Klion points out.


• Still, Klion cautions that he knows plenty of Still, Klion cautions that he knows plenty of athletes who’ve been training for marathons and athletes who’ve been training for marathons and have gained weight because they thought they have gained weight because they thought they could eat whatever they wanted. could eat whatever they wanted.

• So it really does take some planning. So it really does take some planning.


• Normal standards don’t really apply to a Normal standards don’t really apply to a someone like Phelps, who exercises way more someone like Phelps, who exercises way more vigorously than the typical person.vigorously than the typical person.

• Even by athletic standards, Phelps is in his own Even by athletic standards, Phelps is in his own league. league.

• Cyclists in the Tour de France commonly Cyclists in the Tour de France commonly consume a paltry 8,000 to 10,000 calories a day.consume a paltry 8,000 to 10,000 calories a day.

Nutritional Factors Influencing Body Composition.

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