NASM Chapter 17 (Nutrition)

Digestion, absorption, and utilization of proteins

1. 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. 2. The enzyme pepsin begins to cleave the protein strand into smaller polypeptides (strands of several amino acids) and single amino acids. 3. 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. 4. 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. 5. Once in the bloodstream, 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)

Digestion, Absorption, and Utilization of fats

1. Digestion of dietary fat starts in the mouth, moves to the stomach, and is completed in the small intestine. 2. 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 monoglyceride. 3. Absorption of these constituents occurs through the intestinal wall into the blood. 4. In the intestinal wall, they are reassembled into triglycerides that are then released into the lymph in the form of a lipoprotein called chylomicron. 5. Chylomicrons from the lymph move to the blood. 6. The 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.

Kilocalorie

A ____ (kcal) is equal to 1,000 calories. A unit of expression of energy equal to 1,000 calories. The amount of heat energy required to raise the temperature of 1 kilogram or liter of water 1°C. ~ Also called a Calorie (with a capital C)

Calorie

A ____ (lower case c) is a unit of energy and is defined as the amount of heat energy required to raise the temperature of 1 gram of water 1°C.

Complete protein, Incomplete protein

A ____ ____ is a protein that contains all the essential amino acids. ~ Major sources of complete proteins are animal sources, dairy, and meats. ~ Protein quality improves when a small amount of complete protein like dairy food is combined with plant-based foods A ____ ____ is a protein lacking in one of more essential amino acids. ~ The essential amino acid that is missing or present in the smallest amount is called the limiting factor of that protein. ~ Sources of incomplete proteins include grains, legumes, nuts, seeds, and other vegetables. ~ Protein quality also improves when incomplete proteins from plant-based foods such as rice and beans are mixed together.

Monosaccharide

A ____ is a single sugar unit, many of which are connected to make starches and glycogen. ~ These include glucose (commonly referred to as blood sugar), fructose (or fruit sugar), and galactose.

Total energy expenditure

Estimated ____ ____ ____ (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 the sum of three different energy components: 1. Resting metabolic rate (RMR) 2. Thermic effect of food (TEF) 3. Energy expended during physical activity How to calculate: Step 1. Weight (lbs) x 10 = RMR Step 2. RMR x activity factor = TEE This website provides a simple to use calculator to help with the calculations of TEE www.choosemyplate.gov

Guidelines for fluid replacement in the athlete are as follows

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.

Thyroid hormones

High concentrations of ____ ____ tend to cause an increase in RMR, whereas lower then normal levels tend to cause a decrease in RMR.

Review of the Properties of Carbohydrates

One gram of carbohydrate yields 4 calories. Carbohydrates provide the body with: 1. Nutrition that fat and protein cannot (from complex carbohydrates). 2. Satiety by keeping glycogen stores full and adding bulk to the diet. 3. Proper cellular fluid balance, maximizing cellular efficiency. 4. Proper blood sugar levels, if there is a consistent intake of low-glycemic carbohydrates. 5. Spare protein for building muscle. The body needs carbohydrates because: 1. They are the perfect and preferred form of energy. 2. They constantly need to be replaced, causing a craving that must be satisfied. 3. Parts of the central nervous system rely exclusively on carbohydrate. 4. They efficiently burn and use fat and protein. Recommended carbohydrate intake: 1. Daily diet should include 25 to 38 grams of fiber. 2. Carbohydrate intake typically should be between 45 and 65% of total caloric intake according to preference, performance, and satiety. 3. Carbohydrate recommendations should be estimated aft er protein and fat requirements are met. 4. Fruits, whole grains, and vegetables are all excellent sources of fiber.

Sugar

The definition of ____, as it would appear on a food label, is any monosaccharide or disaccharide.

Gluconeogenesis

The formation of glucose from noncarbohydrate sources, such as amino acids to be used as an energy source. ~ This occurs during a negative energy balance ~ Anaerobic or aerobic exercise depletes glycogen, increasing gluconeogenesis.

Protein

The primary function of ____ is to build and repair body tissues and structures. ~ They are made up of amino acids linked together by peptide bonds. ~ It is involved in the synthesis of hormones, enzymes, and other regulatory peptides. ~ Additionally, it can be used for energy if calories or carbohydrates are insufficient. ~ The body uses approximately 20 amino acids to build ifs many different proteins.

Glycemic index

The rate at which ingested carbohydrate raises blood sugar and its accompanying effect on insulin release is referred to as the ____ ____ (GI). ~ The GI for a food is determined when the particular food is consumed by itself on an empty stomach. ~ Mixed meals of protein, other carbohydrate, and fat can alter the glycemic effect of single foods ~ Foods lower on the glycemic index are good sources of complex carbohydrates, as well as being high in fiber and overall nutritional value. ~ High = greater than 70 ~ Moderate = 56 - 69 ~ Low = less than 55

Biologic value

____ ____ (BV) is a measure frequently used when discussing protein sources in popular media and by supplement manufacturers. ~ Essentially, it is a measure of protein quality, or how well it satisfies the body's essential amino acid needs. ~ A higher score provides an amino acid profile that is more closely related to the needs of the human body.

Thermic effect of food

____ ____ ___ ____ (TEF) is the 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.

Resting metabolic rate

____ ____ ____ (RMR) is 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

Energy expended during physical activity

____ ____ ____ ____ ____ is the amount of energy expended above RMR and TEF associated with physical activity. ~ Physical activity accounts for approximately 20% of TEE.

Semiessential amino acids

____ ____ ____ appear to be synthesized to slowly in the body to be Nonessential. ~ Especially important for children ~ Needed to support growth There are 2 semiessential amino acids 1. Arginine 2. Histidine

Nonessential amino acids

____ ____ ____ are manufactured in the body from dietary nitrogen and fragments of carbohydrates and fat. There are 10 nonessential amino acids: 1. Alanine 2. Asparagine 3. Aspartic acid 4. Cysteine 5. Glutamic acid 6. Glutamine 7. Glycine 8. Proline 9. Serine 10. Tyrosine

Essential amino acids

____ ____ ____ cannot be manufactured in the body or are manufactured in insufficient amounts. ~ They must be obtained from the food supply or some other exogenous source. There are 8 essential amino acids: 1. Isoleucine 2. Leucine 3. Lysine 4. Methionine 5. Phenylalanine 6. Threonine 7. Tryptophan 8. Valine

Carbohydrate loading

____ ____ also called glycogen supercompensation, is a technique used to increase muscle glycogen before an endurance event. This practice can nearly double muscle glycogen stores, increasing endurance potential.

Anaerobic exercise, Aerobic exercise

____ ____ involves intense short bursts of activity in which the muscles work so hard that they produce energy without using oxygen. ____ ____ is any activity that uses large muscle groups, is rhythmic in nature, and can be maintained continuously for at least 10 minutes three times a day or for 20 to 30 minutes at one time

Lipids

____ are a group of compounds that include triglycerides (fats and oils), phospholipids, and sterols.

Polysaccharides

____ are carbohydrates that are made up of more than two monosaccharides, and are often called complex carbohydrates. ~ These are primarily starch and fiber. ~ Foods include starch found in plants, seed, and roots. ~ Ultimately converted into simple sugars such as glucose or fructose.

Disaccharides

____ are carbohydrates that are made up of two monosaccharides, meaning two sugar units. ~ These include sucrose (or common sugar), lactose (or milk sugar), and maltose. ~ Ultimately converted into simple sugars such as glucose or fructose.

Carbohydrates

____ are compounds containing carbon, hydrogen, and oxygen and are generally classified as sugars (simple), starches (complex), and fiber. ~ The principal carbohydrates present in food occur in the form of simple sugars, starches, and cellulose. ~ Simple sugars, such as those in honey and fruits, are very easily digested. ~ Double sugars, such as table sugar, require some digestive action but are not nearly as complex as starches, such as those found in whole grain. ~ Starches require prolonged enzymatic action to be broken down into simple sugars (i.e., glucose) for utilization. ~ Cellulose, commonly found in the skins of fruits and vegetables, is largely indigestible by humans and contributes little energy value to the diet. It does, however, provide the bulk necessary for intestinal motility and aids in elimination.

Saturated

____ fatty acids are implicated as a risk factor for heart disease because they raise bad cholesterol levels. ~ Trans-fatty acids have been shown to increase LDL cholesterol and decrease HDL cholesterol, much like saturated fats

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. ~ If there is more than one point of unsaturation, it is classified as a polyunsaturated fatty acid. ~ Unsaturated fatty acids are associated with increases in good cholesterol (high-density lipoproteins; HDL) and decreased risk of heart disease. ~ Monounsaturated fatty acids (found in olive and canola oils) and polyunsaturated fatty acids such as omega-3 fatty acids (found in cold-water fish, 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.

Fiber

____ is an indigestible carbohydrate. ~ Recommended intake is set at 38 grams per day and 25 grams per day for young men and women. ~ There are two types: soluble and insoluble. ~ Soluble fiber is dissolved by water and form a gel-like substance in the digestive tract. Soluble fiber has many benefits, 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 dissolve or absorb in water. It passes through he 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.

Nutrition

____ is defined as the sum of the processes by which an animal or plant takes in and uses food substances for growth and repair of tissues.

Carbohydrate-Intake Recommendations

~ A diet containing between 6 and 10 g/kg per day of carbohydrate (2.7 to 4.5 g/lb), is recommended. ~ 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. ~ 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.

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. ~ Chronic consumption of a high-protein diet is 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. ~ In addition, 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. ~ Possible urinary calcium loss, affecting the bones in the body. ~ Protein requires approximately seven times the water for metabolism than carbohydrate or fat. This leads to possible dehydration if water consumption is not maintained.

Which Is Superior for Weight Loss, a Low-Fat and High-Carbohydrate or a High-Protein and Low-Carbohydrate Diet?

~ 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.

Fat recommendations

~ 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.

Protein's Effect on Satiety (fullness)

~ 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.

Carbohydrate-intake after exercise

~ Consuming 1.5 g per kg of carbohydrate within 30 minutes of completing exercise is recommended to maximize glycogen replenishment. ~ Delaying carbohydrate intake by even 2 hours can decrease total muscle glycogen synthesis by 66%. ~ Additional meals of 1.5 g per kg of carbohydrate every 2 hours are recommended to completely restore muscle glycogen.

Carbohydrate-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. ~ It is 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.

Carbohydrate-intake For Altering Body Composition

~ For most moderately active adults, a carbohydrate intake of between 45 and 65% is recommended. ~ Weight loss or gain is primarily related to total caloric intake, not the macronutrient profile of the diet.

Amino Acids for Immediate Energy

~ If carbohydrate or total energy intake is 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.

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.

Carbohydrate-intake before exercise

~ It is recommended that the individual consume a high-carbohydrate meal 2 to 4 hours before exercising for more than an hour.

Insulin resistance and obesity

~ Metabolic syndrome (syndrome x) is a cluster of symptoms characterized by obesity, insulin resistance, hypertension, and dyslipidemia, leading to an increased risk of cardiovascular disease. ~ If one constantly overeats, excess calories are stored as fat, which causes fat cells to increase in size. Th e 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.

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 fats for: 1. Energy. 2. Structure and membrane function. 3. Precursors to hormones. 4. Cellular signals. 5. Regulation of uptake and excretion of nutrients in the cells. Recommended fat intake: 1. The Acceptable Macronutrient Distribution Range for fat intake for an adult is 20 to 35% of total caloric intake (20 to 25% for athletes). 2. There appears to be no health or performance benefit to consuming less than 15% of energy from fat. 3. A high polyunsaturated-to-saturated fat ratio is desirable. 4. More than 35% leads to overeating (lack of food volume) and often slows metabolism.

The Function of Lipids

~ One gram of fat yields approximately 9 calories when oxidized. ~ 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.

Review of Properties of Protein

~ One gram of protein yields 4 calories. ~ Protein must be broken down completely (into constituent amino acids) before it can be used. Amino acids from protein are used by the body for the following: 1. Synthesizing body-tissue protein. 2. Providing glucose for energy (many can be converted to glucose). 3. Providing nitrogen in the form of amine groups to build nonessential amino acids. 4. Contributing to fat stores. Amino acids are not used to build protein under the following conditions: 1. Not enough available energy from carbohydrate and fat. 2. Consistently low or lacking essential dietary amino acids owing to the exclusive consumption of incomplete proteins. 3. An excess of necessary protein. The following conditions are necessary for the body to synthesize endogenous protein: 1. Availability of all essential and nonessential amino acids in proper amounts. 2. An adequate supply of exogenous protein (supplying amine groups, which synthesize the nonessential amino acids). 3. Adequate energy-yielding carbohydrate and fat (sparing the protein). Recommended protein intake for athletes and exercisers: 1. 1.2 to 1.7 g/kg depending on goal, activity, protein source, and total caloric intake. 2. Typically falls in a range of 10 to 35% of total caloric intake. Chronic high-protein intake (greater than three times the RDA) diets can lead to: 1. Higher intake of saturated fat and low fiber intake. 2. Increased urea production. 3. Decreased glycogen stores. 4. Possible dehydration.

Water

~ Sedentary men and women should consume on average 3.0 L (approximately 13 cups) and 2.2 L (approximately 9 cups) of water per day, respectively. ~ 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. ~ Constitutes approximately 60% of the adult human body by weight.

How much protein is required to build muscle?

~ Skeletal muscle is approximately 72% water, 22% protein, and 6% fat, glycogen, and minerals, and 1 pound of muscle tissue contains approximately 100 grams of protein. ~ Theoretically, an athlete would have to ingest an extra 14 grams of protein per day, 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).

Protein-Intake Recommendations

~ The Recommended Dietary Allowance (RDA) for protein is 0.8 g/kg per day. ~ Acceptable Macronutrient Distribution Range for protein intake for an adult is 10% to 35% of total caloric intake.

Can I Eat Whatever I Want as Long as I Exercise?

~ The majority of daily caloric expenditure is not in the time spent exercising but in the total energy expenditure during 24 hours. ~ 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.