Nutritional Factors Influencing Body Composition

Overconsumption The government recommends 1600 calories a day for the average sedentary woman and 2200 for men.The government recommends 1600 calories a day for the average sedentary woman and 2200 for men. In 2000, our reported per capita daily caloric consumption was 1877 for women and 2618 for men.In 2000, our reported per capita daily caloric consumption was 1877 for women and 2618 for men.

Nutrition and Exercise Where do we get the energy for movement? What should we eat to insure optimal health and fitness?

Nutrition and Exercise Energy for movement comes from the food we eat.Energy for movement comes from the food we eat. The three sources of energy are:The three sources of energy are: –Carbohydrates –Fats –Proteins

Nutrition and Exercise General Recommendations: CHO55-65%CHO55-65% – CNS – Primary fuel source – Only anaerobic fuel source – Required for fat metabolism – Required for protein metabolism

Nutrition and Exercise Fat20-30%Fat20-30% – Major fuel source for endurance activity – Essential component of cell membranes and nerve fibers – Insulation – Shock absorption – Hormone production – Fat soluble vitamins

Nutrition and Exercise FatFat – High in kcal per weight – Low fat = <20% – Read labels - for something to be low fat, there should be no more than 1 gram of fat for every 50 kcals. – 100 kcals : 2 g fat = 18% fat (9 kcals per gram of fat)

Nutrition and Exercise Protein10-15%Protein10-15% – Growth and maintenance of lean tissue – Repair of damaged tissue – Fuel source during starvation

Old Food Guide Pyramid

Food Guide Pyramid Key Points (2004):Key Points (2004): –At least 3 one-ounce servings of whole grains each day (instead of refined sugars and white bread) –Whole grains contain more fiber which has been shown to reduce the risk of heart disease and diabetes –Increase daily intake of fruits and vegetables, whole grains, and nonfat or low fat milk and milk products

Food Guide Pyramid Food Guide Pyramid

Nutrients CHOCHO FatFat ProteinProtein WaterWater VitaminsVitamins MineralsMinerals

Vitamins Fat SolubleFat Soluble – A D E K Water SolubleWater Soluble – B Complex – C

Free Radicals and Antioxidants Free-radical generation increases after acute exercise and potentially causes oxidative tissue damage.Free-radical generation increases after acute exercise and potentially causes oxidative tissue damage. May lead to cancer.May lead to cancer. Consuming antioxidants (e.g., vitamin E and β- carotene) can trap free radicals and prevent this action.Consuming antioxidants (e.g., vitamin E and β- carotene) can trap free radicals and prevent this action.

Minerals CalciumCalcium PhosphorusPhosphorus MagnesiumMagnesium IronIron PotassiumPotassium SodiumSodium

Calcium RDA for most adults = 1000 mgRDA for most adults = 1000 mg –For teenagers = 1300 mg –For those over 50 = 1200 mg –Highest food sources are dairy and calcium- fortified orange juice.

Iron RDA = 8 mg for men and postmenopausal womenRDA = 8 mg for men and postmenopausal 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 upset can occur.

Zinc 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 another vital nutrient, copper.More can block absorption of another vital nutrient, copper.

Water Important before, during, and after physical activity.Important before, during, and after physical activity. 2.5 liters per day.2.5 liters per day. Major factor limiting exercise performance.Major factor limiting exercise performance. Thirst.Thirst.

Dieting Starvation diets will cause weight loss.Starvation diets will cause weight loss. However, they also cause physiologic dysfunction and potentially death.However, they also cause physiologic dysfunction and potentially death. In addition to fat loss, you lose muscle mass, bone mass, and water volume.In addition to fat loss, you lose muscle mass, bone mass, and water volume.

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

Fad Diets Why are they so popular?Why are they so popular? They give the false impression that you can eat what you like, in the quantities that you want, without having to exercise, and still lose weight.They give the false impression that you can eat what you like, in the quantities that you want, without having to exercise, and still lose weight. Very seductive message.Very seductive message.

Low Carb Hype:Hype: –Carbs are not healthy –Carbs negatively impact blood sugar levels through high glycemic index raising insulin levels –Low blood sugar leads to hunger –Invented concept of “Net Carbs”

Low Carb Facts:Facts: –Low blood sugar hasn't been directly linked to hunger. –Unless you have diabetes, blood sugar remains generally stable anyway. –When you stop eating carbohydrates, your brain stops regulating serotonin, a chemical that elevates mood and suppresses appetite.

Low Carb Facts:Facts: –Only carbohydrate consumption naturally stimulates production of serotonin. –When serotonin is made and becomes active in your brain, its effect on your appetite is to make you feel full before your stomach is stuffed and stretched. –The brain makes serotonin only after a person consumes sweet or starchy carbohydrates.

Low Carb Facts:Facts: –The kicker is that these carbohydrates must be eaten in combination with very little or no protein. –This can explain why people may still feel hungry even after they have eaten a 20-ounce steak. –Their stomachs are full but their brains may not be making enough serotonin to shut off their appetites.

Low Carb August 1 st, 2005 Atkins Nutritionals declares bankruptcyAugust 1 st, 2005 Atkins Nutritionals declares bankruptcy

Body Composition Questions Why do low-carbohydrate diets produce such a rapid weight loss?Why do low-carbohydrate diets produce such a rapid weight loss? Diets that limit or totally exclude CHO produce a rapid weight loss.Diets that limit or totally exclude CHO produce a rapid weight loss. When CHO intake is low, muscle glycogen stores are depleted rapidly.When CHO intake is low, muscle glycogen stores are depleted rapidly.

Body Composition Questions For every gram of CHO, 3 grams of H 2 0 are stored in the body.For every gram of CHO, 3 grams of H 2 0 are stored in the body. When glycogen stores are depleted, the loss of water leads to a dramatic weight loss because each liter of water weighs approximately 2 lbs.When glycogen stores are depleted, the loss of water leads to a dramatic weight loss because each liter of water weighs approximately 2 lbs.

Body Composition Questions The weight is regained rapidly, however, when CHO intake returns to normal.The weight is regained rapidly, however, when CHO intake returns to normal.

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

The Zone 1,300 kcal/d for women and 1,700 kcal/d for men1,300 kcal/d for women and 1,700 kcal/d for men Follow the ruleFollow the rule No foods are off limits, but they claim some foods are better than othersNo foods are off limits, but they claim some foods are better than others –Example – broccoli, celery, and grapes = good –Cereal, bagels, and bananas = bad No real justification for these classificationsNo real justification for these classifications

Sugar Busters! 1,200 kcal/d with 28% of total energy intake from fat1,200 kcal/d with 28% of total energy intake from fat 33% of total energy intake from protein33% of total energy intake from protein

South Beach Diet Steer clear of bread and beer (maltose)Steer clear of bread and beer (maltose) No fruit, bread, sugary snacks, potatoes, pasta, or riceNo fruit, bread, sugary snacks, potatoes, pasta, or rice No scientific support for these recommendations, but at least allows whole grains, some fruit (later), and cuts back on saturated fatNo scientific support for these recommendations, but at least allows whole grains, some fruit (later), and cuts back on saturated fat

Nutrition Questions Why are low carbohydrate diets unsafe?Why are low carbohydrate diets unsafe? Low CHO intake may lead to fatigue, hypoglycemia, and ketosis.Low CHO intake may lead to fatigue, hypoglycemia, and ketosis.

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

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

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

Nutrition Questions The nature of low carb diets is a diet low in fruits, vegetables, grains, and beans.The nature of low carb diets is a diet low in fruits, vegetables, grains, and beans. These foods are all high in health promoting and disease preventing properties.These foods are all high in health promoting and disease preventing properties.

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

Nutrition and Exercise Recommended Levels of Protein Consumption RDASedentaryEndurance Strength g/kg/day

Nutrition and Exercise “No valid evidence exists supporting the notion that protein intake exceeding will provide additional advantage”“No valid evidence exists supporting the notion that protein intake exceeding will provide additional advantage” – International Journal of Sports Nutrition

Nutrition and Exercise “The recommended levels may be reached within the total protein percentage recommendations of 10-15% of all calories consumed daily”“The recommended levels may be reached within the total protein percentage recommendations of 10-15% of all calories consumed daily” International Journal of Sports NutritionInternational Journal of Sports Nutrition

Nutrition and Exercise ExampleExample – 220 lbs male = 100 kg – excessive intake = 2.0 (g/kg/day) – daily need = 200 grams – typical consumption = 6000 kcals 10-15% of 6000 kcal = kcal of protein – divided by 4 kcals per gram – grams of protein.

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

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

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

Amino Acids and Protein The most important factors for optimizing growth when one performs resistance exercise are:The most important factors for optimizing growth when one performs resistance exercise are: Adequate resistanceAdequate resistance Adequate caloric consumption, including just after liftingAdequate caloric consumption, including just after lifting Plenty of rest between sessionsPlenty of rest between sessions –(Gibala; Hargreaves, and Tipton, 2000)

Amino Acids and Protein With rare exceptions athletes require 1.2 – 1.6 grams of protein per kg day.With rare exceptions athletes require 1.2 – 1.6 grams of protein per kg day. This amount of protein can almost always be obtained in the normal diet.This amount of protein can almost always be obtained in the normal diet. –(Gibala; Hargreaves, and Tipton, 2000)

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

Nutrition Questions Are high-protein diets safe?Are high-protein diets safe? High-protein diets that limit CHO intake promote muscle tissue loss.High-protein diets that limit CHO intake promote muscle tissue loss. When CHO intake is restricted, the glucose needs of the body are met by breaking down proteins.When CHO intake is restricted, the glucose needs of the body are met by breaking down proteins.

Nutrition Questions Excessive protein intake does not promote protein synthesis.Excessive protein intake does not promote protein synthesis. Instead the excess protein is metabolized.Instead the excess protein is metabolized.

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

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

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

Nutrition Questions Protein intake above 2.8 g/kg/d has been shown to impair renal function.Protein intake above 2.8 g/kg/d has been shown to impair renal function. High-protein diets may promote urinary calcium loss which is particularly a concern for women bodybuilders.High-protein diets may promote urinary calcium loss which is particularly a concern for women bodybuilders.

Nutrition Questions Are high-fat diets unsafe?Are high-fat diets unsafe? YesYes They produce high levels of serum cholesterol and triglycerides which may lead to atherosclerosis.They produce high levels of serum cholesterol and triglycerides which may lead to atherosclerosis.

Nutrition Questions Typically high-fat diets are high in calories, therefore a smaller volume of food must be consumed.Typically high-fat diets are high in calories, therefore a smaller volume of food must be consumed. There are no metabolic pathways in the body for converting fatty acids to glucose, so excess fat is stored in adipose tissue.There are no metabolic pathways in the body for converting fatty acids to glucose, so excess fat is stored in adipose tissue.

Nutrition Questions What is the danger of fasting or skipping meals to promote weight loss?What is the danger of fasting or skipping meals to promote weight loss? Potential side effects include kidney malfunction, hyperuricemia, loss of hair, dizziness, fainting, and muscle cramping.Potential side effects include kidney malfunction, hyperuricemia, loss of hair, dizziness, fainting, and muscle cramping.

Nutrition Questions When the body is deprived of food, it responds by increasing the fat-depositing enzymes and storing more fat.When the body is deprived of food, it responds by increasing the fat-depositing enzymes and storing more fat. The body will also metabolize protein to meet its energy needs.The body will also metabolize protein to meet its energy needs. Body will absorb more of the food that appears in digestive system.Body will absorb more of the food that appears in digestive system.

Nutrition Questions Why should a fat loss diet include at least % carbohydrates?Why should a fat loss diet include at least % carbohydrates? CHO helps maintain normal function of the nervous system because nerve tissue relies solely on glucose as a fuel for energy.CHO helps maintain normal function of the nervous system because nerve tissue relies solely on glucose as a fuel for energy.

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

Nutrition Questions When glycogen stores are depleted, the glucose needs of the body are met through the breakdown of muscle protein.When glycogen stores are depleted, the glucose needs of the body are met through the breakdown of muscle protein. This leads to a loss of lean tissue rather than fat.This leads to a loss of lean tissue rather than fat.

Nutrition Questions CHO is also essential for fat metabolism.CHO is also essential for fat metabolism. When CHOs are restricted or CHO stores are depleted, more fatty acids are mobilized from adipose tissue that can be metabolized by the body.When CHOs are restricted or CHO stores are depleted, more fatty acids are mobilized from adipose tissue that can be metabolized by the body.

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

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

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

Sugared Drinks High levels of intake of sugar-sweetened drinks and of fruit juice raise weight over time in educated women in their 30s (Schulze, 2004)High levels of intake of sugar-sweetened drinks and of fruit juice raise weight over time in educated women in their 30s (Schulze, 2004) Higher intake of diet soft drinks reduces weight gainHigher intake of diet soft drinks reduces weight gain

Sugared Drinks Higher take of sugar-sweetened drinks raise the risk for type 2 diabetes in women without a family history of diabetes.Higher take of sugar-sweetened drinks raise the risk for type 2 diabetes in women without a family history of diabetes. Does not appear true for fruit juiceDoes not appear true for fruit juice

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

Athletes and Nutrition Swimmer Michael Phelps’s next career may be in competitive eating.Swimmer Michael Phelps’s next career may be in competitive eating. Besides grabbing five gold medals at the Beijing Olympics so far, making him the winningest Olympic athlete ever, he’s got to be setting new marks on the chow line.Besides grabbing five gold medals at the Beijing Olympics so far, making him the winningest Olympic athlete ever, he’s got to be setting new marks on the chow line. A New York Post account of Phelps’s… wait for it… 12,000- calorie-a-day diet, gave us a stomachache.A New York Post account of Phelps’s… wait for it… 12,000- calorie-a-day diet, gave us a stomachache.

Athletes and Nutrition Could one human being really consume that much and still be in Phelps’s shape?Could one human being really consume that much and still be in Phelps’s shape? And could this possibly be healthy for Phelps, even considering his five-hours-a-day, six-days- a-week exercise regimen?And could this possibly be healthy for Phelps, even considering his five-hours-a-day, six-days- a-week exercise regimen?

Athletes and Nutrition Here’s Phelps’s typical menu.Here’s Phelps’s typical menu. No, he doesn’t choose among these options.No, he doesn’t choose among these options. He eats them all, according to the Post.He eats them all, according to the Post. Breakfast: Three fried-egg sandwiches loaded with cheese, lettuce, tomatoes, fried onions and mayonnaise. Two cups of coffee. One five-egg omelet. One bowl of grits. Three slices of French toast topped with powdered sugar. Three chocolate-chip pancakes.Breakfast: Three fried-egg sandwiches loaded with cheese, lettuce, tomatoes, fried onions and mayonnaise. Two cups of coffee. One five-egg omelet. One bowl of grits. Three slices of French toast topped with powdered sugar. Three chocolate-chip pancakes.

Athletes and Nutrition Lunch: One pound of enriched pasta. Two large ham and cheese sandwiches with mayo on white bread. Energy drinks packing 1,000 calories.Lunch: One pound of enriched pasta. Two large ham and cheese sandwiches with mayo on white bread. Energy drinks packing 1,000 calories. Dinner: One pound of pasta. An entire pizza. More energy drinks.Dinner: One pound of pasta. An entire pizza. More energy drinks.

Athletes and Nutrition Does a diet like this make sense even for a calorie-incinerating human swimming machine?Does a diet like this make sense even for a calorie-incinerating human swimming machine? If you eat fewer calories than you burn exercising, you lose weight.If you eat fewer calories than you burn exercising, you lose weight.

Athletes and Nutrition But an athlete like Phelps, who exercises up a storm, has to worry about eating enough to replenish the scads of calories he’s burned.But an athlete like Phelps, who exercises up a storm, has to worry about eating enough to replenish the scads of calories he’s burned. If he doesn’t, his “body won’t recover, the muscles will not recover, there will not be adequate energy stored for him to compete in his next event.”If he doesn’t, his “body won’t recover, the muscles will not recover, there will not be adequate energy stored for him to compete in his next event.”

Athletes and Nutrition But what about the choice of foods?But what about the choice of foods? All those eggs and ham and cheese can’t possibly be good for him, can they?All those eggs and ham and cheese can’t possibly be good for him, can they?

Athletes and Nutrition Says Klion, “I think for him, because of his caloric demands, he can probably eat whatever he wants to.”Says Klion, “I think for him, because of his caloric demands, he can probably eat whatever he wants to.” And besides, Klion says, if you’ve got to eat that much, it better be enjoyable, or you won’t be able to keep up.And besides, Klion says, if you’ve got to eat that much, it better be enjoyable, or you won’t be able to keep up. Phelps might not be so eager to shovel down a pound of tofu in a sitting, Klion points out.Phelps might not be so eager to shovel down a pound of tofu in a sitting, Klion points out.

Athletes and Nutrition Still, Klion cautions that he knows plenty of athletes who’ve been training for marathons and have gained weight because they thought they could eat whatever they wanted.Still, Klion cautions that he knows plenty of athletes who’ve been training for marathons and have gained weight because they thought they could eat whatever they wanted. So it really does take some planning.So it really does take some planning.

Athletes and Nutrition Normal standards don’t really apply to a someone like Phelps, who exercises way more vigorously than the typical person.Normal standards don’t really apply to a someone like Phelps, who exercises way more vigorously than the typical person. Even by athletic standards, Phelps is in his own league.Even by athletic standards, Phelps is in his own league. Cyclists in the Tour de France commonly consume a paltry 8,000 to 10,000 calories a day.Cyclists in the Tour de France commonly consume a paltry 8,000 to 10,000 calories a day.