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ISSA Nutritionist practice questions

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Question 1Macronutrients & Micronutrients

How many kilocalories does one gram of dietary protein provide according to the Atwater general factors?

  1. 7 kcal
  2. 9 kcal
  3. 4 kcal Correct answer.
  4. 2 kcal

Explanation

The Atwater general factors assign 4 kcal per gram to protein, matching carbohydrate at 4 kcal per gram and sitting below fat at 9 kcal per gram. Nutritionists use these values to calculate the energy yield of a meal from its macronutrient gram totals.

Question 2Macronutrients & Micronutrients

A client reports eating a food that supplies 20 g carbohydrate, 5 g protein, and 3 g fat. Using Atwater factors, roughly how much energy does this portion provide?

  1. 92 kcal
  2. 127 kcal Correct answer.
  3. 112 kcal
  4. 147 kcal

Explanation

Multiply each gram amount by its factor: 20 x 4 = 80 kcal from carbohydrate, 5 x 4 = 20 kcal from protein, and 3 x 9 = 27 kcal from fat. Summing these gives about 127 kcal for the portion.

Question 3Macronutrients & Micronutrients

Which statement best describes the role of essential amino acids in adult human nutrition?

  1. They are only required during periods of rapid growth such as infancy.
  2. They are stored in adipose tissue and released when protein intake falls.
  3. They must be supplied by the diet because the body cannot make them in sufficient quantity. Correct answer.
  4. They can be synthesized in adequate amounts from carbohydrate carbon skeletons.

Explanation

Essential amino acids cannot be synthesized by the body at a rate that meets needs, so they must come from food. Nonessential amino acids, by contrast, can be produced endogenously from other substrates. Adults require all nine essential amino acids throughout life.

Question 4Macronutrients & Micronutrients

A vegan client eats rice and beans in the same meal. Which nutritional principle does this pairing illustrate?

  1. Protein sparing spares amino acids from oxidation when carbohydrate is adequate
  2. Complementary proteins combine limiting amino acids to improve overall protein quality Correct answer.
  3. Nitrogen balance reflects the difference between intake and excretion of nitrogen
  4. Complete proteins contain all nine essential amino acids from a single animal source

Explanation

Rice is low in lysine while beans are low in methionine, so combining them supplies a fuller essential amino acid profile than either food alone. This is the classic example of complementary proteins improving protein quality within a meal or day.

Question 5Macronutrients & Micronutrients

Which fatty acid is classified as essential for humans?

  1. Palmitic acid
  2. Linoleic acid Correct answer.
  3. Oleic acid
  4. Stearic acid

Explanation

Linoleic acid is an omega-6 polyunsaturated fatty acid that humans cannot synthesize because they lack the delta-12 desaturase needed to introduce a double bond beyond carbon 9. Alpha-linolenic acid is the other essential fatty acid. Oleic, palmitic, and stearic acids can be produced endogenously.

Question 6Macronutrients & Micronutrients

A client wants to increase intake of omega-3 fatty acids. Which food choice provides the richest source of EPA and DHA?

  1. Walnuts
  2. Salmon Correct answer.
  3. Chia seeds
  4. Flaxseed oil

Explanation

Fatty fish such as salmon supply preformed EPA and DHA, the long-chain omega-3 fatty acids with the most established roles in cardiovascular and inflammatory health. Flaxseed, walnuts, and chia are rich in alpha-linolenic acid, which must be converted to EPA and DHA at a low and variable efficiency.

Question 7Macronutrients & Micronutrients

Which statement accurately describes the classification of dietary carbohydrates?

  1. Polysaccharides are long chains of monosaccharides and include starch and glycogen. Correct answer.
  2. Oligosaccharides consist of more than 50 monosaccharide units.
  3. Monosaccharides contain two sugar units joined by a glycosidic bond.
  4. Disaccharides are single sugar molecules such as glucose and fructose.

Explanation

Polysaccharides are polymers of many monosaccharide units; starch, glycogen, and cellulose are examples. Monosaccharides are single units, disaccharides are two units, and oligosaccharides are short chains typically of three to ten units.

Question 8Macronutrients & Micronutrients

A client with lactose intolerance wants to reduce symptoms while keeping dairy in the diet. Which approach is most consistent with the physiology of lactose digestion?

  1. Increase intake of high-fiber starches to stimulate intestinal lactase production
  2. Choose aged hard cheese or lactose-reduced milk and pair dairy with other foods Correct answer.
  3. Drink a large glass of milk on an empty stomach to build tolerance quickly
  4. Avoid all dairy products permanently and rely on calcium supplements alone

Explanation

Lactose intolerance reflects reduced intestinal lactase activity, so smaller lactose loads consumed with other foods are better tolerated. Aged hard cheeses are low in lactose, and lactose-reduced products provide the same nutrients with less substrate for fermentation. This preserves dietary variety and calcium intake.

Question 9Macronutrients & Micronutrients

Which hormone is released from pancreatic beta cells in response to rising blood glucose and promotes cellular glucose uptake?

  1. Insulin Correct answer.
  2. Glucagon
  3. Cortisol
  4. Epinephrine

Explanation

Insulin is secreted by pancreatic beta cells when blood glucose rises and signals tissues such as muscle and adipose to take up glucose. Glucagon, cortisol, and epinephrine act in the opposite direction, raising blood glucose during fasting or stress.

Question 10Macronutrients & Micronutrients

Two foods contain the same amount of carbohydrate per serving, but one is a refined white bread and the other is a whole grain with added fiber. What is the most likely difference in their glycemic response?

  1. The refined bread will produce a lower glucose rise because it is digested more slowly
  2. Both foods will produce identical responses because carbohydrate content is equal
  3. The whole-grain food will produce no rise in blood glucose at all
  4. The whole-grain food will produce a lower and slower glucose rise Correct answer.

Explanation

Fiber, intact grain structure, and slower gastric emptying reduce the rate of glucose absorption, giving whole grains a lower glycemic index than refined bread. Equal carbohydrate content does not mean equal glycemic response because food form and fiber content shape digestion speed.

Question 11Macronutrients & Micronutrients

Which form of stored carbohydrate is found in human muscle and liver and can be broken down to maintain blood glucose between meals?

  1. Pectin
  2. Amylose
  3. Glycogen Correct answer.
  4. Cellulose

Explanation

Glycogen is the branched storage polymer of glucose in human liver and skeletal muscle. Liver glycogen is especially important for maintaining blood glucose during fasting, while muscle glycogen fuels contraction locally.

Question 12Macronutrients & Micronutrients

Which vitamin is a fat-soluble nutrient that functions in blood clotting and requires bile and pancreatic lipase for efficient absorption?

  1. Vitamin B12
  2. Folate
  3. Vitamin C
  4. Vitamin K Correct answer.

Explanation

Vitamin K is fat soluble and is required for the gamma-carboxylation of clotting factors such as prothrombin. Fat-soluble vitamins depend on bile salts and pancreatic lipase for micelle formation and absorption, unlike water-soluble vitamins.

Question 13Macronutrients & Micronutrients

A client following a very low-fat diet for several months is at increased risk of deficiency in which group of nutrients?

  1. Sodium, potassium, and chloride
  2. Thiamin, riboflavin, and niacin
  3. Vitamin C and the B-complex vitamins
  4. Vitamins A, D, E, and K Correct answer.

Explanation

Fat-soluble vitamins A, D, E, and K require dietary fat and bile-mediated micelle formation for absorption, so chronically low fat intake can impair their status. Water-soluble vitamins and electrolytes are absorbed through pathways that do not depend on fat.

Question 14Macronutrients & Micronutrients

Which mineral is a component of hemoglobin and is absorbed more efficiently from animal flesh than from plant foods?

  1. Zinc
  2. Calcium
  3. Iron Correct answer.
  4. Magnesium

Explanation

Iron is central to hemoglobin's oxygen-carrying function. Heme iron from animal flesh is absorbed at a higher rate than nonheme iron from plants, which is also inhibited by phytates and polyphenols.

Question 15Macronutrients & Micronutrients

A vegetarian client eats beans and lentils with most meals. Which dietary practice best improves nonheme iron absorption from these foods?

  1. Increasing phytate-rich bran intake at the same meal
  2. Pairing the meal with a source of vitamin C such as citrus or peppers Correct answer.
  3. Adding calcium-rich dairy to the same meal
  4. Consuming tea or coffee with the meal

Explanation

Vitamin C reduces ferric iron to the more absorbable ferrous form and forms a soluble complex with nonheme iron, enhancing uptake. Tea, coffee, calcium, and phytates inhibit nonheme iron absorption and are better separated from iron-rich meals.

Question 16Macronutrients & Micronutrients

Which statement correctly describes the relationship between sodium and potassium in blood pressure regulation?

  1. High sodium intake and low potassium intake both tend to raise blood pressure Correct answer.
  2. Potassium intake raises blood pressure while sodium lowers it
  3. Only sodium matters; potassium affects bone density but not blood pressure
  4. Sodium and potassium have no interaction in blood pressure control

Explanation

Excess sodium promotes fluid retention and vascular resistance, while adequate potassium supports sodium excretion and vasodilation. Diets high in sodium and low in potassium are consistently associated with higher blood pressure, which is why guidelines emphasize reducing sodium and increasing potassium-rich foods.

Question 17Macronutrients & Micronutrients

Which vitamin functions as a coenzyme in the conversion of pyruvate to acetyl-CoA and is also required for normal neurological function?

  1. Vitamin D
  2. Vitamin B6
  3. Thiamin Correct answer.
  4. Vitamin E

Explanation

Thiamin (vitamin B1) as thiamin pyrophosphate is a coenzyme for pyruvate dehydrogenase, which converts pyruvate to acetyl-CoA, and for alpha-ketoglutarate dehydrogenase. Deficiency causes beriberi and Wernicke-Korsakoff syndrome, reflecting its neurological role.

Question 18Macronutrients & Micronutrients

A client on a strict vegan diet for several years reports fatigue and tingling in the hands. Which nutrient deficiency is most consistent with this presentation?

  1. Vitamin C
  2. Iodine
  3. Riboflavin
  4. Vitamin B12 Correct answer.

Explanation

Vitamin B12 occurs naturally almost exclusively in animal foods, so vegans are at risk unless they consume fortified products or supplements. Deficiency causes megaloblastic anemia and neurological symptoms such as paresthesia, matching the reported fatigue and tingling.

Question 19Macronutrients & Micronutrients

Which statement about dietary fiber and its physiological effects is accurate?

  1. Insoluble fiber is fully fermented by colonic bacteria into short-chain fatty acids
  2. Soluble fiber such as beta-glucan can lower LDL cholesterol by binding bile acids Correct answer.
  3. Fiber increases gastric emptying rate and accelerates glucose absorption
  4. All fiber types provide 4 kcal per gram through small intestinal digestion

Explanation

Soluble fibers such as beta-glucan and psyllium bind bile acids, increasing their excretion and forcing the liver to use cholesterol for bile acid synthesis, which lowers LDL. Insoluble fiber is largely unfermented and speeds transit, while fiber is not digested in the small intestine.

Question 20Macronutrients & Micronutrients

Which amino acid is classified as conditionally essential because its synthesis can become insufficient during critical illness or catabolic stress?

  1. Glutamine Correct answer.
  2. Alanine
  3. Aspartate
  4. Serine

Explanation

Glutamine is normally synthesized in adequate amounts but demand can outstrip supply during severe stress, sepsis, or catabolic illness, making it conditionally essential. Alanine, serine, and aspartate are also nonessential but are not classically described in this conditional role.

Question 21Macronutrients & Micronutrients

A client is advised to increase intake of calcium-rich foods. Which combination best supports calcium absorption?

  1. Calcium with oxalate-rich spinach as the primary source
  2. A single large calcium supplement dose of 1,500 mg with meals
  3. Calcium taken with high-dose iron and zinc supplements
  4. Calcium with adequate vitamin D status and divided doses across the day Correct answer.

Explanation

Vitamin D supports intestinal calcium absorption through calbindin synthesis, and absorption efficiency declines with large single doses, so divided intake is preferable. Oxalates, phytates, and competing minerals such as iron and zinc can reduce calcium availability.

Question 22Macronutrients & Micronutrients

Which statement about trans fatty acids and cardiovascular risk is most accurate?

  1. Trans fats are essential nutrients that must be obtained from the diet
  2. Trans fats lower LDL cholesterol while raising HDL cholesterol
  3. Trans fats have no effect on blood lipids and only add energy
  4. Industrial trans fats raise LDL and lower HDL, worsening the lipid profile Correct answer.

Explanation

Partially hydrogenated oils produce trans fatty acids that raise LDL cholesterol, lower HDL cholesterol, and promote inflammation, which is why many jurisdictions have restricted them. They are not essential and have adverse lipid effects beyond their energy content.

Question 23Macronutrients & Micronutrients

Which mineral is essential for thyroid hormone synthesis and is fortified in table salt in many countries?

  1. Iodine Correct answer.
  2. Selenium
  3. Copper
  4. Manganese

Explanation

Iodine is incorporated into thyroxine and triiodothyronine, and iodized salt is a major public health strategy to prevent goiter and cretinism. Selenium supports deiodinase enzymes but is not part of the hormone itself.

Question 24Macronutrients & Micronutrients

A client reports consuming a high-protein diet with very low carbohydrate intake. Which metabolic adaptation is most likely to occur?

  1. Suppression of lipolysis and ketogenesis by low insulin
  2. Complete cessation of gluconeogenesis because protein supplies all energy
  3. Increased storage of excess protein as muscle glycogen
  4. Increased gluconeogenesis and reliance on ketone bodies for some tissues Correct answer.

Explanation

When carbohydrate intake is very low, hepatic gluconeogenesis from amino acids and glycerol helps maintain blood glucose, and the liver produces ketone bodies that spare glucose for the brain. Low insulin and high glucagon drive lipolysis and ketogenesis rather than suppressing them.

Question 25Macronutrients & Micronutrients

Which vitamin is synthesized in the skin upon exposure to ultraviolet B radiation and also occurs naturally in fatty fish?

  1. Vitamin D Correct answer.
  2. Vitamin E
  3. Vitamin A
  4. Vitamin K

Explanation

Ultraviolet B radiation converts 7-dehydrocholesterol in the skin to previtamin D3, which isomerizes to vitamin D3. Fatty fish and fortified foods are dietary sources, and vitamin D supports calcium absorption and bone health.

Question 26Macronutrients & Micronutrients

Which macronutrient yields the most metabolizable energy per gram when consumed by a healthy adult?

  1. Carbohydrate
  2. Alcohol
  3. Fat Correct answer.
  4. Protein

Explanation

Fat provides about 9 kcal per gram, while carbohydrate and protein each provide about 4 kcal per gram. Alcohol supplies about 7 kcal per gram but is not classified as a macronutrient. Fat therefore has the highest energy density of the energy-yielding nutrients.

Question 27Macronutrients & Micronutrients

Which statement best describes the role of dietary protein in nitrogen balance for a healthy adult?

  1. Nitrogen balance is unrelated to total protein intake and depends only on calorie intake
  2. A positive nitrogen balance is the normal steady state for every healthy adult
  3. Nitrogen intake and excretion are approximately equal in a healthy adult eating adequate protein Correct answer.
  4. Nitrogen intake must exceed nitrogen excretion to maintain body protein stores

Explanation

A healthy adult eating adequate protein and energy is typically in nitrogen equilibrium, meaning intake roughly equals excretion. Positive balance occurs during growth, pregnancy, or recovery, and negative balance occurs with inadequate intake or catabolism. Balance reflects the net of protein synthesis and breakdown.

Question 28Macronutrients & Micronutrients

Which fatty acid is classified as essential because the human body cannot synthesize it in adequate amounts?

  1. Linoleic acid Correct answer.
  2. Oleic acid
  3. Stearic acid
  4. Palmitic acid

Explanation

Linoleic acid is an omega-6 polyunsaturated fatty acid that humans cannot synthesize because they lack the desaturase needed to introduce a double bond beyond carbon 9. It must be supplied by diet. Oleic, palmitic, and stearic acids can be synthesized endogenously.

Question 29Macronutrients & Micronutrients

A client asks why whole grains are preferred over refined grains for carbohydrate intake. Which explanation is most accurate?

  1. Whole grains contain fewer calories per gram than refined grains
  2. Whole grains contain the bran and germ, contributing fiber, B vitamins, and minerals lost during refining Correct answer.
  3. Refined grains cannot be digested and therefore provide no glucose
  4. Whole grains contain no starch and consist entirely of fiber

Explanation

Refining removes the bran and germ, stripping fiber and many micronutrients while leaving mostly the starchy endosperm. Whole grains retain these components, which slow digestion and add vitamins and minerals. Both whole and refined grains provide similar energy per gram.

Question 30Macronutrients & Micronutrients

Which statement about the glycemic response to a meal is most accurate?

  1. It is influenced by food form, fiber content, and the presence of fat and protein Correct answer.
  2. It depends only on the total grams of carbohydrate consumed
  3. It measures the insulin content of a food directly
  4. It is identical for all carbohydrate-containing foods with equal calories

Explanation

The glycemic response reflects how quickly and how much blood glucose rises after eating, which depends on food processing, fiber, accompanying fat and protein, and the type of carbohydrate. Equal carbohydrate grams do not guarantee an equal response. The glycemic index is a property of the food, not a measure of its insulin content.

Question 31Macronutrients & Micronutrients

Which lipid transport particle carries primarily endogenous triglycerides from the liver to peripheral tissues?

  1. Chylomicron
  2. High-density lipoprotein
  3. Low-density lipoprotein
  4. Very-low-density lipoprotein Correct answer.

Explanation

Very-low-density lipoprotein is assembled in the liver and transports endogenously synthesized triglycerides to tissues. Chylomicrons carry dietary fat from the intestine, LDL delivers cholesterol, and HDL participates in reverse cholesterol transport.

Question 32Macronutrients & Micronutrients

Which vitamin is a water-soluble nutrient that functions as a coenzyme in energy metabolism and is found in whole grains, pork, and legumes?

  1. Thiamin Correct answer.
  2. Folate
  3. Vitamin C
  4. Riboflavin

Explanation

Thiamin (vitamin B1) is water-soluble and acts as a coenzyme, including in the conversion of pyruvate to acetyl-CoA. Pork, whole grains, and legumes are notable sources. Its deficiency causes beriberi and, in alcohol misuse, Wernicke encephalopathy.

Question 33Macronutrients & Micronutrients

A client who avoids all animal products wants to meet vitamin B12 needs. Which recommendation is most appropriate?

  1. Rely on spinach and other leafy greens as a B12 source
  2. Consume more whole grains, which are naturally rich in B12
  3. Use fortified plant milks or a vitamin B12 supplement Correct answer.
  4. Increase sunlight exposure to stimulate B12 synthesis

Explanation

Vitamin B12 occurs naturally almost exclusively in animal-derived foods, so vegans need fortified products or a supplement. Plant foods such as leafy greens and grains do not provide reliable B12. Sunlight synthesizes vitamin D, not B12.

Question 34Macronutrients & Micronutrients

Which mineral is a cofactor for enzymes involved in antioxidant defense and is found in Brazil nuts, seafood, and meat?

  1. Selenium Correct answer.
  2. Chloride
  3. Phosphorus
  4. Calcium

Explanation

Selenium is incorporated into glutathione peroxidase and other selenoproteins that help protect cells from oxidative damage. Brazil nuts, seafood, and meat are rich sources. Calcium, phosphorus, and chloride serve mainly structural, electrolyte, and acid-base functions.

Question 35Macronutrients & Micronutrients

Which form of vitamin A is found in animal foods such as liver and is readily absorbed as retinol?

  1. Preformed vitamin A Correct answer.
  2. Beta-carotene
  3. Lutein
  4. Lycopene

Explanation

Preformed vitamin A, primarily as retinyl esters and retinol, occurs in animal foods such as liver, eggs, and dairy. Beta-carotene is a provitamin A carotenoid from plants that must be converted. Lycopene and lutein are carotenoids without vitamin A activity.

Question 36Macronutrients & Micronutrients

A client taking a high-dose calcium supplement with meals also takes an iron supplement. Which interaction is most relevant?

  1. Calcium enhances iron absorption when taken together
  2. Iron enhances calcium absorption and should be taken together
  3. Calcium and iron compete for absorption, so separating doses may improve iron uptake Correct answer.
  4. Calcium converts iron into a form that is more easily absorbed

Explanation

Calcium and iron share absorptive pathways, and large calcium doses can inhibit iron absorption when consumed together. Separating the supplements by a few hours reduces this competition. This is a recognized mineral-mineral interaction.

Question 37Macronutrients & Micronutrients

Which statement accurately describes the role of water as a nutrient?

  1. It provides energy through hydrolysis of macronutrients
  2. It is stored in large reserves and deficiency develops slowly over months
  3. It acts as a solvent and participates in temperature regulation and transport Correct answer.
  4. It is only needed when a client is visibly thirsty

Explanation

Water is the solvent for body fluids, transports nutrients and wastes, and supports thermoregulation through sweating and evaporation. It is not an energy source. Body water is lost continuously, so intake must replace ongoing losses rather than waiting for thirst.

Question 38Macronutrients & Micronutrients

A client eating a high-fiber diet reports bloating and gas after rapidly increasing fiber intake. Which explanation is most accurate?

  1. Fiber is fermented by gut bacteria, producing gas, and rapid increases overwhelm tolerance Correct answer.
  2. Fiber blocks protein digestion, leading to bacterial overgrowth
  3. Fiber is completely absorbed in the small intestine and causes osmotic water retention
  4. Fiber contains lactose, which causes gas in most adults

Explanation

Many fibers are fermented by colonic bacteria, producing short-chain fatty acids and gas. A rapid increase can cause bloating until the microbiota and tolerance adapt. Gradual increases with adequate fluid are usually recommended.

Question 39Macronutrients & Micronutrients

Which statement about protein quality is most accurate?

  1. Plant proteins are always incomplete and cannot meet essential amino acid needs
  2. Protein quality depends only on the total grams consumed
  3. A protein is complete if it supplies all essential amino acids in adequate amounts Correct answer.
  4. Complementary proteins must be eaten in the same bite to be effective

Explanation

Protein quality reflects the essential amino acid profile and digestibility. A complete protein supplies all essential amino acids in adequate proportions. Plant proteins can meet needs when varied, and complementary proteins do not need to be consumed at the same meal, only within the same day.

Question 40Macronutrients & Micronutrients

Which statement about the metabolism of excess dietary carbohydrate is most accurate?

  1. It is excreted unchanged in the urine
  2. It is converted directly to urea and eliminated
  3. It is converted to fatty acids in the liver and stored as fat when glycogen stores are full Correct answer.
  4. It is stored as protein in skeletal muscle

Explanation

When glycogen stores are saturated, excess carbohydrate can be converted to fatty acids through de novo lipogenesis in the liver. The resulting triglycerides are stored in adipose tissue. Carbohydrate is not excreted unchanged in meaningful amounts or converted to urea.

Question 41Metabolism & Energy Balance

What does the thermic effect of food (TEF) represent in total daily energy expenditure?

  1. The energy stored as fat after a caloric surplus
  2. The energy used to maintain body temperature at rest
  3. The energy burned during structured exercise sessions
  4. The energy cost of digesting, absorbing, and metabolizing ingested nutrients Correct answer.

Explanation

TEF is the energy expended above basal needs to process food, typically estimated at about 10% of intake, though protein has a higher TEF than fat or carbohydrate. It is a distinct component from physical activity and resting metabolic rate.

Question 42Metabolism & Energy Balance

Which macronutrient has the highest thermic effect of food per unit of energy consumed?

  1. Carbohydrate
  2. Fat
  3. Protein Correct answer.
  4. Alcohol

Explanation

Protein has the highest TEF, often cited at roughly 20-30% of its energy content, because amino acid processing, deamination, and urea synthesis are energetically costly. Fat has the lowest TEF, around 0-3%.

Question 43Metabolism & Energy Balance

A client reports eating 2,400 kcal per day and maintaining weight. If dietary protein provides 25% of intake and protein's TEF is about 25%, roughly how many calories per day are expended on processing that protein?

  1. 60 kcal
  2. 600 kcal
  3. 300 kcal
  4. 150 kcal Correct answer.

Explanation

Protein intake is 0.25 × 2,400 = 600 kcal. Applying a 25% TEF to that 600 kcal gives about 150 kcal expended in processing. The remaining 450 kcal of protein energy is available to the body.

Question 44Metabolism & Energy Balance

Which statement correctly describes the relationship between resting metabolic rate (RMR) and basal metabolic rate (BMR)?

  1. RMR and BMR are identical measurements taken under the same conditions
  2. BMR is measured after light activity and is therefore higher than RMR
  3. BMR includes the thermic effect of food while RMR excludes it
  4. RMR is measured under less strict conditions and typically runs slightly higher than BMR Correct answer.

Explanation

BMR requires strict conditions such as overnight fasting, complete rest, and a thermoneutral environment. RMR uses looser conditions, so it usually comes out about 10% higher than BMR. Neither measure includes the thermic effect of a meal.

Question 45Metabolism & Energy Balance

Which component typically accounts for the largest share of total daily energy expenditure in a sedentary adult?

  1. Thermic effect of food
  2. Non-exercise activity thermogenesis
  3. Exercise activity thermogenesis
  4. Resting metabolic rate Correct answer.

Explanation

Resting metabolic rate usually contributes roughly 60-70% of total daily expenditure, making it the dominant component. Activity thermogenesis and TEF are smaller and more variable.

Question 46Metabolism & Energy Balance

Which equation is the standard calculation for respiratory quotient (RQ)?

  1. RQ = carbon dioxide produced ÷ oxygen consumed Correct answer.
  2. RQ = carbohydrate oxidized ÷ fat oxidized
  3. RQ = energy produced ÷ oxygen consumed
  4. RQ = oxygen consumed ÷ carbon dioxide produced

Explanation

RQ is the ratio of CO2 exhaled to O2 inhaled at the tissue level. It reflects the fuel mix being oxidized, ranging near 0.7 for fat and near 1.0 for carbohydrate.

Question 47Metabolism & Energy Balance

A respiratory quotient of approximately 0.70 indicates that the primary fuel being oxidized is which of the following?

  1. Protein
  2. Fat Correct answer.
  3. A 50/50 blend of carbohydrate and fat
  4. Carbohydrate

Explanation

An RQ near 0.70 corresponds almost entirely to fat oxidation, because fat yields less CO2 per O2 consumed. Pure carbohydrate oxidation approaches an RQ of 1.0, and protein sits near 0.82.

Question 48Metabolism & Energy Balance

Why does respiratory exchange ratio (RER) measured at the mouth sometimes exceed 1.0 during intense exercise?

  1. Oxygen consumption rises faster than carbon dioxide production
  2. Hyperventilation blows off CO2 faster than it is produced metabolically Correct answer.
  3. Protein becomes the dominant fuel during sprinting
  4. Fat oxidation increases sharply at high intensities

Explanation

RER is the whole-body gas exchange ratio measured at the mouth. At high intensity, ventilation can exceed metabolic CO2 production, pushing RER above 1.0, so it no longer equals tissue-level RQ.

Question 49Metabolism & Energy Balance

Which hormone is released from adipose tissue to signal satiety to the hypothalamus?

  1. Insulin
  2. Ghrelin
  3. Glucagon
  4. Leptin Correct answer.

Explanation

Leptin is secreted by adipocytes in proportion to fat mass and acts on hypothalamic receptors to reduce appetite and support energy balance. Ghrelin is the main orexigenic hormone and rises before meals.

Question 50Metabolism & Energy Balance

A client in a sustained caloric deficit reports constant hunger despite losing fat. Which hormonal pattern best explains this response?

  1. Leptin falls and ghrelin rises Correct answer.
  2. Both leptin and ghrelin rise
  3. Both leptin and ghrelin fall
  4. Leptin rises and ghrelin falls

Explanation

As fat mass and energy availability decline, leptin secretion drops while ghrelin typically increases, producing a coordinated drive to eat. This adaptive response helps explain hunger and adherence challenges during dieting.