Chapter 17: nutrition
how may carbs be beneficial to an endurance athlete
a carb-rich diet will build glycogen stores and aid in performance and recovery
Thermic Effect of Food (TEF)
When food is consumed it is mechanically digested and moved through the digestive tract. Nutrients are transported from the gut to the blood, where they are distributed throughout the body. All of these processes require energy that can be measured aft er the meal is consumed: This increase in energy expenditure after the meal; comprises approximately 6% to 10% of total energy expenditure depending on the frequency and energy content of the meal.
t or f; a study of type 2 diabetics, those with IR, and people of normal weight found that 3 weeks of a high-carbohydrate, low-fat diet and an exercise program significantly lowered insulin levels
true!
t or f; Because dehydration of as little as 3% can impair performance, athletes and active individuals ingesting extra protein should weigh themselves regularly to ensure they are properly hydrated
true! drink your water
Calories (upper case C) or kilocalorie (kcal)
is equal to 1,000 calories. Although not technically correct, calorie, Calorie, and kilocalorie are used interchangeably in nonscientific, everyday language.
what are the basic nutritional guidelines for altering body composition for lean body mass gain
◆ Eat four to six meals a day. Insulin response to a meal stimulates protein synthesis. ◆ Spread protein intake throughout the day to take advantage of the previous tip. ◆ Keep in mind the post-workout window of opportunity. Ingestion of protein and carbohydrate within 90 minutes of a workout will increase recovery and protein synthesis, maximizing gains. This may be most easily accomplished with a liquid meal-replacement formula that can be absorbed quickly owing to being predigested. Food may take several hours to digest and absorb, missing the window. ◆ Do not neglect the importance of carbohydrate and fat. It takes more than protein to increase lean body mass
Consuming an adequate amount of water will benefit the body in the following ways
◆ Endocrine gland function improves. ◆ Fluid retention is alleviated. ◆ Liver functions improve, increasing the percentage of fat used for energy. ◆ Natural thirst returns. ◆ Metabolic functions improve. ◆ Nutrients are distributed throughout the body. ◆ Body-temperature regulation improves. ◆ Blood volume is maintained.
Chronic high-protein intake (greater than three times the RDA) diets can lead to:
◆ Higher intake of saturated fat and low fiber intake ◆ Increased urea production ◆ Decreased glycogen stores ◆ Possible dehydration
what are the basic nutritional guidelines for altering body composition for fat loss
◆ Make small decreases in food and beverage calories and increase physical activity. ◆ Distribute protein, carbohydrate, and fat throughout the day and at each meal. ◆ Consume less than 10% of calories from saturated fat. ◆ Choose whole grains and fiber-rich fruits and vegetables over refined grains and simple sugars (as the fiber and complexity of the starch will aid in hunger control). ◆ Limit alcohol consumption. ◆ Schedule no fewer than four and as many as six meals a day. This helps to control hunger, minimize blood sugar fluctuations, and increase energy levels throughout the day. ◆ Avoid empty calories and highly processed foods, which contain many calories and do little to provide satiety. ◆ Drink plenty of water (minimum of 9 to 13 cups per day). ◆ Have clients weigh and measure food for at least 1 week. This will make them more aware of caloric values and serving sizes, as well as decrease the likelihood of underreporting calories.
Amino acids are not used to build protein under the following conditions:
◆ Not enough available energy from carbohydrate and fat ◆ Consistently low or lacking essential dietary amino acids owing to the exclusive consumption of incomplete proteins ◆ An excess of necessary protein
Sedentary men and women should consume on average _____ L (approximately 13 cups) and _____ L (approximately 9 cups) of water per day, respectively
3.0 L, 2.2 L: -Those participating in a fat-loss program should drink an additional 8 ounces of water for every 25 pounds they carry above their ideal weight. Water intake should also be increased if an individual is exercising briskly or residing in a hot climate
Within how many minutes should a client consume 1.5 g/kg of carbohydrates to maximize glycogen replenishment after exercise?
30 min
A personal trainer is advising a client on caloric distribution. Which of the following falls within the Acceptable Macronutrient Distribution Range (AMDR) for protein?
30%
one gram of protein yields ___ calories
4
A diet containing between ___ and ______ g/kg per day of carbohydrate (2.7 to 4.5 g/lb), is recommended
6 and 10
What is the recommended daily intake for carbohydrates?
6-10 g/kg body weight
Resting metabolic rate accounts for what percentage of total energy expenditure?
70%
What is a high-protein diet commonly associated with?
A decrease in glycogen stores
what are negative side-effects associated with chronic use of high-protein diets:
A high-protein diet is typically defined as one that consists of more than 35% of total caloric intake from protein, or three times the protein RDA for athletes: -generally associated with a higher intake of saturated fat and low fiber intake, both of which are risk factors for heart disease and some types of cancer -because the kidneys are required to work harder to eliminate the increased urea produced, caution should always be taken when recommending high-protein intakes to people with a history of kidney problems such as renal insufficiency or kidney stones -there is a need for greater fluid consumption when consuming large quantities of protein. Protein requires approximately seven times the water for metabolism than carbohydrate or fat (dehydration concern)
what is the cause of insulin resistance
Although there is some evidence that there may be a genetic component that contributes to insulin resistance (IR), the condition itself will not allow for weight gain without an energy intake in excess of expenditure. In fact, obesity itself is a risk factor for development of IR, not the other way around: -If one constantly overeats, excess calories are stored as fat, which causes fat cells to increase in size. The growing fat cell itself becomes insulin resistant, and the resulting prevalence of FFA will cause the body to favor the use of fat for energy at the expense of glucose. This becomes a vicious cycle with the overweight condition leading to IR, which in turn leads to impaired glucose use. Blood sugar levels rise, insulin levels rise, and cholesterol, triglycerides, and blood pressure rise as well. To make matters worse, the impaired ability of glucose to enter muscle cells keeps glycogen stores lower, which can increase appetite, motivating the individual to eat more, increasing fat stores, exacerbating IR, and so on
Energy Expended During Physical Activity
Any physical activity requires energy expenditure above resting metabolism: -Physical activity can account for 20% or more of an individual's TEE, although the exact percentage can vary greatly depending on an individual's current fitness level and the type, intensity, and duration of physical activity or exercise engaged in. Physical activity can be influenced more dramatically than RMR and TEF, which for the most part are relatively constant.
Can I Eat Whatever I Want as Long as I Exercise?
Approximately 3,500 calories equals a pound of body fat, so to lose 1 to 2 pounds per week, a client must maintain an average caloric deficit of 500 to 1,000 calories per day -However, a person may burn 250 calories from exercise and spend the rest of the day participating in sedentary activities -Calories that are not used for energy production are stored as fat. Therefore, a person can eat 100 calories a day more than what their body needs to maintain, and in the course of 35 days, theoretically they will gain a pound of fat. Even a mere 10 extra calories a day over daily maintenance needs could add up to a 1 pound of weight gain over 350 days
what is proteins role on satiety
As with all macronutrients, protein activates specific satiety mechanisms and may be more satiating than fat and carbohydrate. Protein-induced suppression of food intake in animals and humans is greater than its energy content alone, which suggests that protein has a direct effect on satiety
how can caloric intake influence protein intake:
Because protein can be used for tissue repair and synthesis as well as for energy, protein requirements will increase as total energy intake decreases: -As total caloric intake is reduced, energy needs may no longer be satisfied by carbohydrate and fat intake alone, necessitating that protein be used to provide energy -The goal is to satisfy the majority of energy needs with carbohydrate and fat, saving protein for tissue repair and growth. This is why carbohydrates are often referred to as protein sparing. If one does not eat adequate amounts of carbohydrate and fat (as is often seen in low-calorie or low-carbohydrate diets or during physique-competition preparation), more protein will be used for energy by default
how should protein intake be determined with a bodybuilder:
Bodybuilders during positive energy balance (off -season) should follow the same protein recommendations as strength athletes. However, during negative energy balance (used to create competition-level body-fat percentages), protein requirements may dramatically increase. To reach competitive body-fat levels, calorie intake is continually lowered while exercise (such as cardiorespiratory training, weight training, and posing) is increased: -Competitive levels of body fat are generally unhealthy and impossible to maintain for prolonged periods: because of its anabolic requirements, protein intake cannot be lowered; In fact, protein intake may have to be increased in the final weeks before competition. -During this period, the body must have the option to use available food either for energy or muscle support. The body does not have a choice with dietary carbohydrate or fat, making them the only dispensable calories. Therefore, protein intake could be dramatically increased to theoretically lessen the obligatory loss of lean tissue during drastic training measures -during the off-szn; athletes return to normal food intake or protein at anabolic requirements and energy needs met primarily with carbohydrates and fats) and normal energy balance
how can exercise influence protein intake:
Both anaerobic and aerobic exercise can affect protein requirements in different ways: - Exercise increases the oxidation of amino acids as well as the rate of protein turnover in lean body mass during recovery. Because different types of exercise have specific effects, an individual participating in both types of exercise may have a need for protein greater than someone involved in only one
Carbohydrate and Performance
Carbohydrate availability is vital for maximal sports performance: -When performing high-intensity, short duration activity (anaerobic), muscular demand for energy is provided for and dependent on muscle glycogen: -During endurance exercise (aerobic) performed at a moderate intensity (60% of maximal oxygen consumption [Vo 2 max]), muscle glycogen provides approximately 50% of energy needs -During high-intensity aerobic exercise (>79% of Vo 2 max), it yields nearly all of the energy need -Duration of exercise also affects the amount of glycogen used for energy: As duration of activity increases, available glucose and glycogen diminish, increasing the reliance on fat as a fuel source -Ultimately, the limiting factor for exercise performance is carbohydrate availability: "Fat burns in a carbohydrate flame." That is to say, maximal fat utilization cannot occur without sufficient carbohydrate to continue Krebs cycle activity -When an endurance athlete "hits the wall," it is the result of fatigue caused by severely lowered liver and muscle glycogen. Th is occurs even though there is sufficient oxygen being delivered to the muscles and an abundance of potential energy from fat stores
Recommendations for fat intake
Clients must be satiated by the amount of calories necessary to allow fat loss or energy balance or they will eventually overeat: -goal is to keep the client's diet within the guidelines for health. According to the Institute of Medicine, the Acceptable Macronutrient Distribution Range for fat intake for an adult is 20 to 35% of total caloric intake -Athletes are recommended to consume 20 to 25% of total calories from fat, but there appears to be no health or performance benefit to consuming less than 15% of energy from fat -Conversely, higher-fat diets are not conducive to successful weight loss or maintenance and appear to increase the ease with which the body converts ingested calories to body fat
Which of the following actions falls outside a personal trainer's scope of practice?
Counsel a client with anorexia about the health benefits of a well-balanced diet
explain the linkage between fat and satiety
Dietary fats stimulate the release of CCK, a hormone that signals satiety: -Additionally, fats slow the digestion of foods (and thus the nutrient content in the bloodstream), assisting in blood sugar stabilization (Reducing blood sugar fluctuations can contribute to satiety)
Protein foods
Dietary protein is the delivery vehicle for amino acids: - Meats, fruits, vegetables, grains, dairy products, and even supplements supply us with the valuable building blocks of protein we need.
the science behind digestion, absorption, and utilization of fats
Digestion of dietary fat starts in the mouth, moves to the stomach, and is completed in the small intestine: -In the intestine, the fat interacts with bile to become emulsified so that pancreatic enzymes can break the triglycerides down into two fatty acids and a mono-glyceride -Absorption of these constituents occurs through the intestinal wall into the blood -In the intestinal wall, they are reassembled into triglycerides that are then released into the lymph in the form of a lipoprotein called chylomicron -Chylomicrons from the lymph move to the blood. Th e triglyceride content of chylomicron is removed by the action of the enzyme lipoprotein lipase (LPL), and the released fatty acids are taken up by the tissues. Th roughout the day, triglycerides are constantly cycled in and out of tissues, including muscles, organs, and adipose.
What are the facts about weight loss/gain?
Eat fewer calories than are expended and there will be a reduction in weight. Conversely, consume more calories than are expended and there will be an increase in weight: -many factors that affect both: today's environment provides a constant supply of food containing an increasing energy intake while a sedentary lifestyle is followed (reducing energy expenditure)
how can a negative energy balance influence protein intake:
For clients pursuing body-fat reduction, body-fat loss goals require that a caloric deficit be maintained until the goal is reached: -this results in amino acids being used to assist in energy production (gluconeogenesis); Anaerobic or aerobic exercise depletes glycogen, increasing gluconeogenesis. -The increase in gluconeogenesis is supported by the release of branched-chain and other amino acids from structural proteins to maintain glucose homeostasis during exercise -A hypocaloric diet establishes less-than-optimal glycogen stores, and when this is combined with increased glycogen demand during exercise, protein's energy utilization is increased -therefore, there is a great need for protein; however also getting optimal carb and fat values will go a long way in allowing protein to do what is supposed to do primarily; tissue repair
explain the science of carb intake during exercise
For exercise lasting more than 1 hour, carbohydrate feedings during exercise can help supply glucose to working muscles whose glycogen stores are dwindling: -also maintains blood glucose levels, increasing time to exhaustion by 20 to 60 minutes -recommended that endurance athletes consume between 30 and 60 g of carbohydrate every hour to accomplish this -Popular sports beverages are perfect for this goal and have the added benefit of replacing fluid losses, also benefiting performance. The replacement of carbohydrate and water has individual benefits that together are additive
how can the amount of carbs in your diet affect performance
High-carbohydrate diets increase the use of glycogen as fuel, whereas a high-fat diet increases the use of fat as fuel; However, a high-fat diet results in lower glycogen synthesis
incomplete proteins
If a food source is low or lacking in one or more essential amino acids
complete protein
If a food supplies all of the essential amino acids in appropriate ratios
Amino Acids for Potential Energy (Fat)
If protein intake exceeds the need for synthesis and energy needs are met, then amino acids from dietary protein are deaminated, and their carbon fragments may be stored as fat
explain the science behind "Carbohydrate Loading"
In endurance exercise of greater than a 90-minute duration (e.g., marathon running), muscle-glycogen stores become depleted. Th is depletion limits the performance of endurance exercise. Carbohydrate loading, also called glycogen super-compensation, is a technique used to increase muscle glycogen before an endurance event. Th is practice can nearly double muscle glycogen stores, increasing endurance potential
What Are the Risks of Starvation (Very Low Calorie) Diets?
Most nutrition experts do not recommend an energy intake any lower than 1,200 calories and even that may be too low for an active or very large person: -Very low calorie diets (VLCD) should be followed only under the supervision of a medical professional. A VLCD is a doctor-supervised diet that typically uses commercially prepared formulas to promote rapid weight loss in patients who are obese. These formulas, usually liquid shakes or bars, replace all food intake for several weeks or months. VLCD formulas need to contain appropriate levels of vitamins and micronutrients to ensure that patients meet their nutritional requirements. People on a VLCD consume about 800 calories per day or less - must be used under medical supervision; VLCD can provide great benefits when used the right way; not meant to be used forever, however it can provide great wonders in bouts for certain cliental Some of the risks of following an overly restrictive diet include: ◆ Increased risk of malnutrition ◆ Poor energy and inability to complete the essential fitness program ◆ A behavioral "pendulum" swing—an inability to reintroduce "forbidden foods" in a moderate manner ◆ Many patients on a VLCD for 4 to 16 weeks report minor side effects such as fatigue, constipation, nausea, or diarrhea. The most common serious side effect is gallstone formation. People who are obese, especially women, are at a higher risk of getting gallstones, and they are even more common during rapid weight loss *fitness professionals should discourage overly restrictive programs advocating less than 1,000 to 1,200 calories per day, and support safe, maintainable weight loss by means of more healthful eating, smaller portions, and increased activity
One of Peter's personal training clients has specific nutritional requirements. Why would Peter refer this client to a registered dietician?
Nutritional counseling does not fall within Peter's scope of practice.
Metabolic syndrome is a cluster of symptoms characterized by what conditions?
Obesity, insulin resistance, hypertension, dyslipidemia
review of the properties of lipids
One gram of fat yields 9 calories. Fat is generally insoluble in water. Fat is present in all cells: high in adipose and nerve tissue, low in epithelial and muscle tissue. Fatty acids can be saturated, polyunsaturated, and monounsaturated the body needs fat for: ◆ Energy ◆ Structure and membrane function ◆ Precursors to hormones ◆ Cellular signals ◆ Regulation of uptake and excretion of nutrients in the cells recommended fat intake: ◆ The Acceptable Macronutrient Distribution Range for fat intake for an adult is 20 to 35% of total caloric intake (20 to 25% for athletes). ◆ There appears to be no health or performance benefit to consuming less than 15% of energy from fat. ◆ A high polyunsaturated-to-saturated fat ratio is desirable. ◆ More than 35% leads to overeating (lack of food volume) and often slows metabolism
Role of Fiber in Health
One of the greatest contributions made by dietary complex carbohydrate is fiber: -high fiber intakes are associated with lower incidence of heart disease and certain types of cancer -there are two types of fiber: soluble and insoluble Soluble fiber: - dissolved by water and forms a gel-like substance in the digestive tract; includes many benefits such as including moderating blood glucose levels and lowering cholesterol. Good sources of soluble fiber include oats and oatmeal, legumes (peas, beans, lentils), barley, and many uncooked fruits and vegetables (especially oranges, apples, and carrots) insoluble fiber: -does not absorb or dissolve in water. It passes through the digestive tract close to its original form. Insoluble fiber offers many benefits to intestinal health, including a reduction in the risk and occurrence of colorectal cancer, hemorrhoids, and constipation; Most of insoluble fibers come from the bran layers of cereal grains Additional benefits of fiber include: ◆ Provides bulk in the diet, thus increasing the satiety value of foods. ◆ Some fibers also delay the emptying of the stomach, further increasing satiety ◆ Prevents constipation and establishes regular bowel movements. ◆ May reduce the risks of heart and artery disease by lowering blood cholesterol. ◆ Regulates the body's absorption of glucose (diabetics included), perhaps because fiber is believed to be capable of controlling the rate of digestion and assimilation of carbohydrates. ◆ High-fiber meals have been shown to exert regulatory effects on blood glucose levels for up to 5 hours aft er eating
Educational and Professional Requirements for the RD
Personal trainers are not licensed health-care professionals (unless they have additional training and education) but oft en give nutrition advice to their clients. Th us, it is important for all personal trainers to be aware of the standards of practice and scope of practice guidelines that pertain to them.
explain the science behind carb intake after exercise
Repeated days of strenuous exercise take a toll on an individual's glycogen stores. A high-carbohydrate intake helps to replenish glycogen stores; however, the timing of carbohydrate ingestion can also be important to maximizing recovery: -Consuming 1.5 g per kg of carbohydrate within 30 minutes of completing exercise is recommended to maximize glycogen replenishment -The post-workout environment may hasten glycogen repletion as a result of increased blood fl ow to the muscles and an increased sensitivity of the cells to the effects of insulin -Additional meals of 1.5 g per kg of carbohydrate every 2 hours are recommended to completely restore muscle glycogen
show an example of finding TEE
Step 1: 180 (Ib) x 10= 1,800 RMR Step 2: 1,800 (RMR) x 2.1 (activity factor) = 3,780 calories expended per day (TEE)
how may the ability for a protein to satisfy the essential amino acid requirements be quantified:
Terms used to rate dietary protein include protein efficiency ratio (PER), net protein utilization (NPU), and biologic value (BV): -BV is a measure of protein quality, or how well it satisfies the body's essential amino acid needs
protein intake recommendations
Th e Recommended Dietary Allowance (RDA) for protein is 0.8 g/kg per day. The Acceptable Macronutrient Distribution Range for protein intake for an adult is 10% to 35% of total caloric intake: -These protein recommendations range from 10% to 35% of total caloric intake, which allows not only for differences in goals and activity but also for bio-individuality in terms of satiety and performance. -people respond better to slightly higher/lower protein intakes
Is Consuming a High-Protein Diet Superior for Muscle Gain?
Th e body needs the correct amount of protein, carbohydrate, and fat to grow, maintain, and repair itself, including the growth of lean body mass: -Amino acids, the component blocks of proteins, are used as building materials for the body. Whether "building" a hormone, an antibody, an enzyme, or a biceps muscle, the body relies on its reserve of amino acids to build proteins as needed. Resistance training, and to a certain extent all exercise, increases the body's need for repair material. Therefore, an active individual needs more protein than a sedentary individual -the scientifically based recommendation for strength athletes range from 0.5 to 0.8 grams of protein per pound (1.2 to 1.7 g per kg) -the right amount of protein (and the obligatory resistance training) will support hypertrophy, and an excess of protein above total calorie needs will be stored as body fat.
limiting factor of that protein
Th e essential amino acid that is missing or present in the smallest amount
describe the relationship between water and performance
Th e importance of proper hydration cannot be stressed enough: -The body cannot adapt to dehydration, which impairs every physiologic function -Studies have shown that a fluid loss of even 2% of body weight will adversely affect circulatory functions and decrease performance levels *However, if a fairly regular daily pattern of exercise and water and food consumption is followed, average body weight will provide a very good index of the body's state of hydration
Digestion, Absorption, and Utilization of carbohydrates
The principal carbohydrates present in food occur in the form of simple sugars, starches, and cellulose: -simple sugars are easily digested; while double sugars require some digestive action but are not nearly as complex as starches (which require prolonged enzymatic action to be broken down into simple sugars; ie- glucose, for utilization) -cellulose (largely indigestible by humans and contributes little energy to the diet; does, however, provide the bulk necessary for intestinal motility and aids in elimination) -Through the processes of digestion and absorption, all disaccharides and polysaccharides are ultimately converted into simple sugars such as glucose or fructose (However, fructose must be converted to glucose in the liver before it can be used for energy) -Some of the glucose (or blood sugar) is used as fuel by tissues of the brain, nervous system, and muscles. Because humans are periodic eaters, a small portion of the glucose is converted to glycogen aft er a meal and stored within the liver and muscles. Any excess is converted to fat and stored throughout the body as a reserve source of energy. When total caloric intake exceeds output, any excess carbohydrate, dietary fat, or protein may be stored as body fat until energy expenditure once again exceeds energy input.
Glycemic Index (GI)
The rate at which ingested carbohydrate raises blood sugar and its accompanying effect on insulin release: -foods lower on the glycemic index are good sources of complex carbohydrates, as well as being high in fiber and overall nutritional value
what is the importance of water
Water is vital to life itself; it constitutes approximately 60% of the adult human body by weight: -Whereas deficiencies of nutrients such as the macronutrients, vitamins, and minerals may take weeks or even years to develop, one can only survive for a few days without water
Does Eating at Night Make Me Fat?
Weight gain is a result of eating more calories than you burn on a regular basis, not when you eat. Because of their preference or schedule, many people eat later in the evening, before bed, or even wake up in the middle of the night to take in calories. If one gains weight doing this, it is because of excess calorie intake, not the timing -We all have a certain number of calories that we can consume without gaining weight. As long as we do not exceed that number, weight gain will not occur.
metabolic syndrome
a cluster of symptoms characterized by obesity, insulin resistance, hypertension, and dyslipidemia, leading to an increased risk of cardiovascular disease. Syndrome X is usually associated with obesity (especially abdominal), a high-fat diet, and a sedentary lifestyle: -common denominator associated with these factors is high levels of circulating free fatty acids (FFA); In the presence of high FFA concentrations, the body will favor their use as energy, decreasing glucose oxidation and glycogen synthesis and inhibiting glucose transport. The result is chronically elevated levels of blood sugar levels, a condition called hyperglycemia. During states of hyperglycemia, insulin will also be elevated, leading to the conversion of the excess blood sugar to other products such as glycoproteins and fatty acids.
what if the athlete is unable to have a carb-rich meal 2 to 4 hours before exercise?
a liquid meal such as a meal-replacement formula may be used. One advantage to such formulas is their quick gastric emptying time. Some research recommends a carbohydrate intake of 1 to 4.5 g/kg, between 1 and 4 hours before exercise: -In this study, the group ingesting 4.5 g/kg of carbohydrate 4 hours before exercise saw performance improved by 15% -To avoid gastrointestinal distress, smaller meals should be consumed closer to the exercise session
breakdown the science behind the digestion, absorption, and synthesis sequence of protein in the body:
a) As ingested proteins enter the stomach, they encounter hydrochloric acid (HCl), which uncoils (or denatures ) the protein so that digestive enzymes can begin dismantling the peptide bonds -In addition, the enzyme pepsin begins to cleave the protein strand into smaller polypeptides (strands of several amino acids) and single amino acids b)As these protein fragments leave the stomach and enter the small intestine, pancreatic and intestinal proteases (or protein enzymes) continue to dismantle the protein fragments. c)The resulting dipeptides, tripeptides, and single amino acids are then absorbed through the intestinal wall into the enterocytes and released into the blood supply to the liver d)once in the blood stream the free-form amino acids have several possible fates: they can be used for protein synthesis (building and repairing tissues or structures), immediate energy, or potential energy (fat storage).
Resting Metabolic Rate (RMR)
accounts for approximately 70% of total daily energy expenditure in the sedentary person, although it may vary among individuals: -can be affected by a wide variety of factors including age, sex, genetics, hormonal changes, body size, body composition, temperature, altitude, illness, medication, food and caffeine intake, and cigarette smoking. Constant factors that cannot be altered are age, sex, and genetics -exercise is said to have a positive effect on RMR indirectly if fat-free mass (FFM) is increased or decreased
estimated total energy expenditure (TEE)
also referred to as total daily energy expenditure (TDEE), is defined as the amount of energy (calories) spent, on average, in a typical day. TEE is actually the sum total of three different energy components: ◆ Resting metabolic rate (RMR) : The amount of energy expended while at rest; represents the minimal amount of energy required to sustain vital bodily functions such as blood circulation, respiration, and temperature regulation. RMR typically accounts for 70% of TEE. ◆ Thermic effect of food (TEF): Th e amount of energy expended above RMR as a result of the processing of food (digestion) for storage and use. TEF typically accounts for approximately 6-10% of TEE. ◆ Energy expended during physical activity: Th e amount of energy expended above RMR and TEF associated with physical activity. Physical activity accounts for approximately 20% of TEE.
structure of protein
amino acids linked together by peptide bonds: -The body uses approximately 20 amino acids to build its many different proteins -arranging the amino acids in different sequences yields the body's myriad of proteins (from a muscle protein like actin to proteins that make up the lens of the eye).
nonessential amino acids
amino acids that the body can synthesize: -the body is able to manufacture them from dietary nitrogen and fragments of carbohydrate and fat -Because of their rate of synthesis within the body, arginine and histidine are considered semi-essential amino acids. It appears that these amino acids cannot be manufactured by the body at a rate that will support growth (especially in children)
Only during the last two decades has there been a significant increase in obesity. The data support two primary variables responsible for this dramatic rise in obesity:
an increased energy intake and a reduction in energy expenditure: -It is estimated that more than 75% of the American adult population does not partake, on a daily basis, in 30 minutes of low-to-moderate physical activity
what are the major sources of complete proteins
animal sources, dairy, and meats
t or f; It is important that personal trainers have a network of qualified health-care professionals (physicians, dieticians, eating-disorder specialists, and other health-care professionals) in their area to which they can refer clients with health or medical-related problems.
big facts
t or f; Th ere is no need to reduce carbohydrate percentage and carbohydrate-rich whole foods to lose fat. America's increasing problem of obesity is not a direct result of carbohydrate intake, but rather one of energy imbalance.
big facts
Protein
build and repair body tissues and structures. It is also involved in the synthesis of hormones, enzymes, and other regulatory peptides. Additionally, protein can be used for energy if calories or carbohydrate are insufficient in the diet
although most experts believe the single most important factor in gaining lean mass (along with resistance training, of course) is consuming adequate ____________
calories; -Therefore, to ensure the body has sufficient energy for lean mass accretion, consume an additional 200 to 400 calories daily (3 to 5 calories per kg or 1.5 to 2.5 calories per pound per day) above maintenance requirements in addition to consuming a little extra protein (approximately 2 ounces of lean meat).
what are some of the benefits of an individually planned nutrition strategy?
can enhance the results from the stimulus of exercise, improve health and athletic performance, reduce the risk of disease and illness, increase energy levels, and favorably alter body composition in clients
essential amino acids
cannot be manufactured by the body (or made in insufficient amounts); must be obtained from food supply or some other exogenous source: -total of 8 essential aminos
Which of the following macronutrients has an acceptable macronutrient distribution range in the 45 - 65% total caloric intake?
carbs
Carbohydrates
compounds containing carbon, hydrogen, and oxygen and are generally classified as sugars (simple), starches (complex), and fiber: - The definition of sugar, as it would appear on a food label, is any monosaccharide or disaccharide *Carbohydrates are a chief source of energy for all body functions and muscular exertion: This fact leads to a rapid depletion of available and stored carbohydrates and creates a continual craving for this macronutrient. Carbohydrates also help regulate the digestion and utilization of protein and fat
Amino Acids for Immediate Energy
due to the bodies need for constant energy (in the brain and in the NS), for glucose in particular: -if glucose levels are too low, the body has the ability to use amino acids (from dietary or body proteins) to provide energy -The amino acids are first deaminated (or stripped of the amine group), allowing the remaining carbon skeleton to be used for the production of glucose or ketones to be used for energy. The removed amine group produces ammonia, a toxic compound, which is converted to urea in the liver and excreted as urine by the kidneys
What is a basic nutritional recommendation for clients who want to gain lean body mass?
eat 4 to 6 meals per day
what are the two general classes of amino acids
essential and nonessential amino acids
t or f; Thirst alone is a good indicator of how much water is needed
false; thirst is a poor indicator of how much water is needed: -instead, A good way to keep track of how much one needs to drink is to first determine his or her average daily weight. Use this number as the standard for the person's euhydrated (or normal) state; Do not begin a practice session or endurance competition until the body is at, or slightly above, its standard weight. Drink enough water, juice, or sports drinks during exercise to maintain the starting weight
Estimating Total Daily Energy Expenditure
first estimate RMR, then multiply RMR by an appropriate activity factor. There are several different prediction equations used to estimate RMR. Such simplified equations can provide a reasonable estimate of TEE in most cases. The following is an example of a simplified TEE calculation: Step 1. Weight (lbs) x 10 RMR Step 2. RMR x activity factor = TEE
what are the major sources of incomplete proteins
grains, legumes, nuts, seeds, and other vegetables. Barley, cornmeal, oats, buckwheat, pasta, rye, wheat, beans, lentils, dried peas, peanuts, chickpeas, soy products, sesame seeds, sunflower seeds, walnuts, cashews, pumpkin seeds, and other nuts are the main sources of incomplete proteins *Incomplete proteins can be combined to make available all of the essential amino acids and form a complete protein
Lipids
group of compounds that include triglycerides (fats and oils), phospholipids, and sterols: -Of the lipids contained in food, 95% are fats and oils. In the body, 99% of the stored lipids are also triglycerides -Structurally, triglycerides are three fatty acids attached to a glycerol backbone
explain the pros/cons of MCT supplementation
has been suggested that MCT could benefit endurance performance by supplying an exogenous energy source in addition to carbohydrate during exercise and increase plasma free fatty acids (FFA), sparing muscle glycogen: -however, several studies on well-trained endurance athletes have found that MCT ingestion does not alter fat metabolism, spare muscle glycogen, or improve performance -Goedecke et al. ( 130 ) found that ingestion of MCT with ultra-endurance cyclists actually compromised performance. The impaired performance may have been related to the gastrointestinal upset from the MCT solution.
saturated fats
implicated as a risk factor for heart disease because they raise bad cholesterol levels (low-density lipoproteins; LDL), whereas unsaturated fats are associated with increases in good cholesterol (high-density lipoproteins; HDL) and decreased risk of heart disease
explain the science behind fat supplementation during exercise
in general, fat is digested and absorbed quite slowly: -Long-chain triglycerides (LCT), which make up the majority of dietary fatty acids (16 to 18 carbons), must go through the process of digestion and absorption described earlier before they can be utilized -Medium-chain triglycerides (MCT), however, are more rapidly absorbed (do not require incorporation into chylomicrons for transport, but can enter the systemic circulation directly through the portal vein, providing a readily available, concentrated source of energy)
which of the following is an effect of dehydration?
increased HR
what are the factors that influence protein requirements
individual's daily exercise and physical activity levels, daily caloric consumption, body-composition goals, and sports-performance goals.
What is a unit of expression of energy equal to 1,000 calories?
kilocalorie
Polysaccharides
long chains of monosaccharide units linked together and found in foods that contain starch and fiber: -foods are oft en called complex carbohydrates and include starch found in plants, seed, and roots -Complex carbohydrates are primarily starch and fiber, and the starch is digested to glucose. -Dietary fiber is a part of the plant that cannot be digested by human gut enzymes and passes through the small intestine and colon, where it is expelled as fecal material or fermented and used as food by the gut bacteria
what two things can weight lost on a low-carb diet be attributed to
low caloric intake or fat-free mass (FFM)
unsaturated fatty acids
may be further classified according to their degree of unsaturation: -If the fatty acid has one double bond in its carbon chain, it is called a monounsaturated fatty acid; Monounsaturated fatty acids (found in olive and canola oils) and polyunsaturated fatty acids such as omega-3 fatty acids (found in cold-water fi sh, such as salmon) are considered to have favorable effects on blood lipid profiles and may play a role in the treatment and prevention of heart disease, hypertension, arthritis, and cancer -If there is more than one point of unsaturation, it is classified as a polyunsaturated fatty acid; Polyunsaturated fatty acids provide important essential fatty acids (or fats that cannot be manufactured by the body but are essential for proper health and functioning)
trans fatty acid (trans fat)
prevalent fatty acid in today's food supply is trans-fatty acids, the result of hydrogenation (or the process of adding hydrogen to unsaturated fatty acids to make them harder at room temperature and increase food shelf-life): -Trans-fatty acids have been shown to increase LDL cholesterol and decrease HDL cholesterol, much like saturated fats
For which of the following is building and repairing body tissues and structures a primary function?
protein
The Function of Lipids
most concentrated source of energy in the diet. One gram of fat yields approximately 9 calories when oxidized, furnishing more than twice the calories per gram of carbohydrates or proteins: -In addition to providing energy, fats act as carriers for the fat-soluble vitamins A, D, E, and K. Vitamin D aids in the absorption of calcium, making it available to body tissues, particularly to the bones and teeth -Fats are also important for the conversion of carotene to vitamin A fats are also involved in the following: ◆ Cellular membrane structure and function ◆ Precursors to hormones ◆ Cellular signals ◆ Regulation and excretion of nutrients in the cells ◆ Surrounding, protecting, and holding in place organs, such as the kidneys, heart, and liver ◆ Insulating the body from environmental temperature changes and preserving body heat ◆ Prolonging the digestive process by slowing the stomach's secretions of hydrochloric acid, creating a longer-lasting sensation of fullness aft er a meal ◆ Initiating the release of the hormone cholecystokinin (CCK), which contributes to satiety
Which Is Superior for Weight Loss, a Low-Fat and High-Carbohydrate or a High-Protein and Low-Carbohydrate Diet?
neither is superior: -Weight loss is achieved when calories consumed are less than calories expended -According to research, people initially lose weight faster on a low-carbohydrate and high-protein diet when compared with energy equivalent low-fat and high-carbohydrate diets. But aft er 12 months, the total weight loss is similar -Because of individual responses, it is not appropriate to recommend "one" weight loss plan for the entire population. The primary goal in weight loss is to improve health by lowering body fat while maintaining or increasing the proportion of FFM and muscle tissue. If FFM and muscle can be increased during weight loss, it is easier to maintain RMR and fat loss. Maintaining muscle is also important to strength and the ability to perform physical activities of daily living
Do carbs make you fat?
no: -necessary nutrients; provide energy for the body, metabolism of fats, spare muscle proteins, and provide essential fiber, vitamins, and minerals. Excess intake of any nutrient, carbohydrate, fat, protein, or alcohol over daily calorie needs will cause weight gain. -selecting carbs that are moderate to low glycemic foods and high in fiber can help with satiety, blood sugar regulation, and energy balance indirectly -overconsumption of sugar, refined processed carbs, and high-glycemic foods could lead to uncontrolled spikes in blood sugar, low energy, and increased appetite; Therefore, to avoid hunger, it is advised to choose unprocessed, whole-food carbohydrate sources such as vegetables, starchy vegetables, whole fruit, and grains to provide fiber vitamins, and minerals for healthy weight loss. In addition, carbohydrate is imperative to glycogen repletion before, during and aft er exercise for strength, power, aerobic and anaerobic performance, and conditioning *The Acceptable Macronutrient Distribution Range for carbohydrate intake for an adult is 45 to 65% of total caloric intake
what are some of the negatives associated with carb loading
periods of hypoglycemia, irritability, increased susceptibility to injury, and difficulty in compliance: -Although maximizing muscle glycogen before an event may improve power, performance, output, and speed by postponing muscle glycogen depletion, glycogen loading before exercise does not always improve performance -Some athletes experience extreme gastrointestinal distress including diarrhea when attempting glycogen loading. Th us, meals should contain familiar foods that are relatively low in fat and fiber to minimize gastrointestinal distress. Because leg muscles become heavier with the addition of glycogen and water, many athletes complain they feel heavy and sluggish, and they can experience a slight weight gain. Athletes should experiment with glycogen loading before using it for competition
digestion, absorption, utilization of proteins
proteins must be broken down into the constituent aminos before the body can use them to build or repair tissue or as an energy substrate: -The fate of the amino acids aft er digestion and absorption by the intestines depends on the body's homeostatic needs, which can range from tissue replacement or tissue addition to a need for energy
how many hours are recommended before exercises to consume carbs
recommended that the indiv consumes a high carb meal 2 to 4 hours before exercising for more than an hour: -this allows for appropriate gastric emptying before exercise -especially helpful for morning workouts when glycogen stores are lowered by as much as 80%
Which of the following careers require a licensure exam for entry?
registered dietician
Decreased levels of thyroid hormones tend to cause a decrease in which of the following?
resting metabolic rate (RMR)
fatty acids may be _________ or __________
saturated or unsaturated
carbs for altering body composition
should make up the highest % of macronutrient cals when attempting to achieve fat loss/gain: -Carbohydrates provide variety, valuable nutrients, and volume to the diet. The satiating value of complex carbohydrate is especially important when one is in a caloric deficit for the goal of fat loss -For most moderately active adults, a carbohydrate intake of between 45 and 65% is recommended, which will provide sufficient food volume and the fuel necessary for energy and productive workouts -Weight loss or gain is primarily related to total caloric intake, not the macronutrient profile of the diet
monosaccharide
single sugar unit: -many of which are connected to make starches (the storage form of carbohydrates in plants) and glycogen (the storage form of carbohydrates in humans) -Monosaccharides include glucose (commonly referred to as blood sugar), fructose (or fruit sugar), and galactose. Disaccharides (two sugar units) include sucrose (or common sugar), lactose (or milk sugar), and maltose
A client tells the personal trainer that she wants to increase lean body mass. Which of the following nutritional strategies should the trainer recommend?
spread protein intake throughout the day
nutrition
sum of the processes by which an animal or plant takes in and uses food substances for growth and repair of tissues: -also plays a huge role in the health, appearance, performance, and well-being of an individual
t or f; According to the Institute of Medicine, the Acceptable Macronutrient Distribution Range for carbohydrate intake for an adult is 45 to 65% of total caloric intake
true
t or f; At the turn of the century, carbohydrate intake as a percentage of total energy was higher, fat as a percentage was lower, and obesity was not the problem it is today. Currently, total fat intake is higher, carbohydrate is lower, and obesity has reached epidemic proportions
true
t or f; Because the process of protein synthesis works on an all-or-none principle, all amino acids must be present at the site of protein manufacture, or synthesis will be reduced to the point at which the cell runs out of the limiting amino acid
true
t or f; Chronic or acute illness as well as hormonal changes and certain types of medications can influence RMR as well
true
t or f; Complex carbohydrates (such as whole grains and fresh fruits and vegetables) should constitute the majority of calories because of their nutrient-dense (providing B vitamins, iron, and fiber) nature
true
t or f; Delaying carbohydrate intake by even 2 hours can decrease total muscle glycogen synthesis by 66%
true
t or f; It is important for personal trainers to be aware of any long-term medications their clients may be taking that can potentially affect the individual's metabolic rate.
true
t or f; Sports beverages including potassium and sodium help replace electrolytes, whereas carbohydrates provide energy. Sports beverages containing 6% to 8% carbohydrate are recommended for exercise lasting longer than 1 hour
true
t or f; Long-term success in weight loss is associated with a realistic eating style, not one that severely limits or omits one of the macronutrients
true!
t or f; providing individual nutrition assessment, meal plans, or recommendations for nutritional therapy are best left to an RD or other qualified licensed professionals.
true; Th e skills and abilities required to calculate, counsel, or prescribe an individualized nutrition or weight-management plan exceeds the training and expertise of the personal trainer. Th is becomes especially important if the client has health and medical concerns such as obesity, diabetes, heart disease, allergies, or hypertension: Personal trainers are, however, encouraged to help educate their clients with respect to making healthy food choices. Th e majority of clients seeking personal training services oft en have numerous misconceptions about diet, nutrition, and weight loss. It is vital that personal trainers help educate them by providing factual information on safe and effective diet, weight-loss, and nutritional methods
t or f; Fat has a lower thermic effect than other macronutrients
true; The thermic effect of a food (TEF) is the rise in metabolic rate that occurs after the food is ingested. Typically, TEF amounts to 10% of ingested calories: -As fat percentage in the diet increases, the amount of heat given off (TEF) decreases -Conversely, as carbohydrate percentage in the diet increases, so does the TEF. It is metabolically inexpensive to convert dietary fat to body-fat stores. Only 3% of the calories in fat are required to store it as fat. In contrast, it takes 23% of the calories in carbohydrate to convert it to body fat
t or f; As numerous studies point out, high-fat diets are strongly associated with obesity, and thus insulin resistance and diabetes
true; however, eating fats does not make one fat (same as carbs) unless it is consumed in excess of energy requirements; However, it is easier to consume excess energy (or be hyper-phagic) on a high-fat diet, owing to fat's high caloric density: -When large quantities of high-caloric-dense foods are consumed in combination with excess calories and a sedentary lifestyle, it is easy to envision an abundance of fatty acids floating around in the bloodstream *It is much more likely that a high-fat diet leads to excess consumption of calories, obesity, IR, and eventually non-insulin-dependent diabetes mellitus than it is that carbohydrates cause IR and, as a result, obesity: only solution is a diet containing the appropriate amount of energy, high in fibrous vegetables or starchy carbohydrates, and exercise
t or f; If an individual begins dropping carbohydrate-rich foods from his or her diet, it is inevitable that caloric intake will drop as a result.
true; in addition, this will also result in dwindling glycogen stores (For every gram of glucose taken out of glycogen, it brings with it 2.7 g of water; This loss of muscle glycogen (including water) can be quite significant in the first week of a low-carbohydrate diet, and adds to the pounds lost on the scale. This is how low-carbohydrate fad diets can promise dramatic weight loss in such a short period)
t or f; Protein quality improves when a small amount of complete protein like a dairy food is combined with plant-based foods and when incomplete proteins from plant-based foods such as rice and beans are mixed together.
true; the power of variety!
calorie (cal)
unit of energy and is defined as the amount of heat energy required to raise the temperature of 1 gram of water 1 degree Celsius
historically, how is carb loading implemented
weeklong program includes 4 days of glycogen depletion (through a low-carbohydrate diet that is approximately 10% of calories and exhaustive exercise), followed by 3 days of rest and a high-carbohydrate diet (approximately 90% of calories)
Recommended protein intake for athletes and exercisers:
◆ 1.2 to 1.7 g/kg depending on goal, activity, protein source, and total caloric intake ◆ Typically falls in a range of 10 to 35% of total caloric intake
Th e following conditions are necessary for the body to synthesize endogenous protein:
◆ Availability of all essential and nonessential amino acids in proper amounts ◆ An adequate supply of exogenous protein (supplying amine groups, which synthesize the nonessential amino acids) ◆ Adequate energy-yielding carbohydrate and fat (sparing the protein)
Guidelines for fluid replacement in the athlete are as follows
◆ Consume 14 to 22 ounces (1.75 to 2.75 cups) of fluid 2 hours before exercise. ◆ Drink 6 to 12 ounces of fluid for every 15 to 20 minutes of exercise. ◆ Fluids should be cold because of more rapid gastric emptying. ◆ If exercise exceeds 60 minutes, use of a sports drink (containing up to 8% carbohydrate) can replace both fluid and dwindling muscle glycogen stores. ◆ When exercising for less than 60 minutes, water is the experts' choice for fluid replacement. ◆ The goal is to replace sweat and urine losses. ◆ Ingest 16 to 24 ounces of fluid for every pound of body weight lost after an exercise bout, especially if rapid rehydration is necessary, as in twice-a-day training
Recommended carbohydrate intake:
◆ Daily diet should include 25 to 38 g of fiber. ◆ Carbohydrate intake typically should be between 45 and 65% of total caloric intake according to preference, performance, and satiety. ◆ Carbohydrate recommendations should be estimated aft er protein and fat requirements are met. ◆ Fruits, whole grains, and vegetables are all excellent sources of fiber.
One gram of carbohydrate yields 4 calories. Carbohydrates provide the body with:
◆ Nutrition that fat and protein cannot (from complex carbohydrates) ◆ Satiety by keeping glycogen stores full and adding bulk to the diet ◆ Proper cellular fluid balance, maximizing cellular efficiency ◆ Proper blood sugar levels, if there is a consistent intake of low-glycemic carbohydrates ◆ Spare protein for building muscle
Amino acids from protein are used by the body for the following:
◆ Synthesizing body-tissue protein ◆ Providing glucose for energy (many can be converted to glucose) ◆ Providing nitrogen in the form of amine groups to build nonessential amino acids ◆ Contributing to fat stores
The body needs carbohydrates because:
◆ They are the perfect and preferred form of energy ◆ They constantly need to be replaced, causing a craving that must be satisfied ◆ Parts of the central nervous system rely exclusively on carbohydrate ◆ They efficiently burn and use fat and protein
supplemental protein may be useful:
◆ To quickly get amino acids into the blood before and aft er weight training ◆ To replace whole-food proteins for weight loss ◆ In situations when whole food is not available ◆ For bodybuilders, wrestlers, or other weight-conscious athletes preparing for competition
