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Question 1Food and Nutrition Science Knowledge

Using Atwater factors, approximately how many kilocalories are provided by 10 g of dietary protein?

  1. 100 kcal
  2. 70 kcal
  3. 90 kcal
  4. 40 kcal Correct answer.

Explanation

Atwater factors assign 4 kcal per gram to protein, so 10 g supplies about 40 kcal. Fat supplies 9 kcal/g and alcohol 7 kcal/g, which is why those values appear as distractors.

Question 2Food and Nutrition Science Knowledge

Which of the following vitamins is water-soluble?

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

Explanation

Water-soluble vitamins include ascorbic acid and the B-complex group; they are absorbed directly into the portal circulation and excess is largely excreted in urine. Vitamins A, D, E and K are fat-soluble and require micellar solubilization.

Question 3Food and Nutrition Science Knowledge

Which pair of fatty acids is considered essential for humans?

  1. Oleic acid and stearic acid
  2. Arachidonic acid and eicosapentaenoic acid
  3. Palmitic acid and butyric acid
  4. Linoleic acid and alpha-linolenic acid Correct answer.

Explanation

Humans lack the desaturases needed to introduce double bonds beyond carbon 9, so linoleic acid (omega-6) and alpha-linolenic acid (omega-3) must come from the diet. The other fatty acids listed can be synthesized endogenously or derived from these precursors.

Question 4Food and Nutrition Science Knowledge

An adult weighs 70 kg and is 1.75 m tall. What is this person's body mass index?

  1. 20.0 kg/m2
  2. 24.5 kg/m2
  3. 22.9 kg/m2 Correct answer.
  4. 26.1 kg/m2

Explanation

BMI is calculated as weight in kilograms divided by height in meters squared. Here 70 divided by 3.0625 equals approximately 22.9, which falls within the normal range of 18.5 to 24.9.

Question 5Food and Nutrition Science Knowledge

Which temperature range corresponds to the food safety danger zone in which bacteria multiply most rapidly?

  1. 60 to 100 degrees Celsius
  2. 5 to 60 degrees Celsius Correct answer.
  3. Minus 18 to 0 degrees Celsius
  4. 0 to 5 degrees Celsius

Explanation

Bacterial growth is most rapid between roughly 5 and 60 degrees Celsius, so perishable foods should be held outside this band. Refrigeration below 5 degrees Celsius and hot holding above 60 degrees Celsius limit multiplication.

Question 6Food and Nutrition Science Knowledge

Under ordinary conditions, which monosaccharide is the obligatory fuel for the brain and red blood cells?

  1. Fructose
  2. Galactose
  3. Glucose Correct answer.
  4. Xylose

Explanation

The brain and erythrocytes rely on glucose because they lack the capacity to use fructose or galactose directly at a meaningful rate. Other monosaccharides must first be converted to glucose or to glycolytic intermediates.

Question 7Food and Nutrition Science Knowledge

Night blindness and xerophthalmia are classically associated with a deficiency of which nutrient?

  1. Vitamin C
  2. Vitamin A Correct answer.
  3. Vitamin D
  4. Vitamin B12

Explanation

Vitamin A supplies retinal, which is required for rhodopsin formation in the rod cells, and maintains the integrity of the corneal epithelium. Deficiency therefore impairs dark adaptation and can progress to xerophthalmia.

Question 8Food and Nutrition Science Knowledge

Which statement describes a characteristic effect of soluble fiber?

  1. It raises postprandial blood glucose
  2. It binds bile acids and lowers LDL cholesterol Correct answer.
  3. It adds insoluble bulk to stool
  4. It is fully digested in the small intestine

Explanation

Soluble fibers such as beta-glucan and pectin form viscous gels that trap bile acids and increase their excretion, forcing hepatic cholesterol uptake and lowering LDL. They also blunt postprandial glucose excursions rather than raising them.

Question 9Food and Nutrition Science Knowledge

Which nutrient enhances the absorption of non-heme iron from a mixed meal?

  1. Tannic acid
  2. Phytic acid
  3. Vitamin C Correct answer.
  4. Calcium

Explanation

Ascorbic acid reduces ferric iron to the more absorbable ferrous form and forms a soluble chelate with iron, counteracting inhibitors. Calcium, phytates and polyphenols such as tannins reduce non-heme iron absorption.

Question 10Food and Nutrition Science Knowledge

Which amino acid is typically the limiting one in milled rice protein?

  1. Tryptophan
  2. Methionine
  3. Lysine Correct answer.
  4. Leucine

Explanation

Cereal proteins are generally low in lysine relative to the reference pattern, and rice is no exception, making lysine first limiting. Legumes are conversely rich in lysine but low in the sulfur-containing amino acids.

Question 11Food and Nutrition Science Knowledge

The glycemic index of a food is best described as which of the following?

  1. Blood glucose rise after a set carbohydrate load versus a reference food Correct answer.
  2. Insulin response to a test meal
  3. Rate of gastric emptying after eating
  4. Total sugar content of a food

Explanation

The glycemic index compares the incremental blood glucose response to a fixed amount of available carbohydrate from a test food with that of a reference food such as glucose. It is a ratio of responses, not a measure of total sugar or of insulin secretion.

Question 12Food and Nutrition Science Knowledge

What is the first principle of the Hazard Analysis and Critical Control Point system?

  1. Conduct a hazard analysis Correct answer.
  2. Establish verification procedures
  3. Establish corrective actions
  4. Determine critical control points

Explanation

HACCP begins with a systematic hazard analysis that identifies biological, chemical and physical hazards and the steps at which they may be controlled. Only after hazards are identified can critical control points, limits and monitoring procedures be set.

Question 13Food and Nutrition Science Knowledge

Kwashiorkor is best characterized by which feature?

  1. Excess vitamin A intake
  2. Iron overload from supplementation
  3. Severe energy deficiency without edema
  4. Severe protein deficiency accompanied by edema Correct answer.

Explanation

Kwashiorkor results from a diet adequate in energy but grossly deficient in protein, producing hypoalbuminemia and peripheral edema. Marasmus, by contrast, reflects severe overall energy deficiency with marked wasting and no edema.

Question 14Food and Nutrition Science Knowledge

Which statement correctly defines the Recommended Dietary Allowance?

  1. The intake meeting the needs of nearly all healthy individuals Correct answer.
  2. The highest intake unlikely to cause harm
  3. The intake adequate for people with a specific disease
  4. The average intake sufficient for half of healthy people

Explanation

The RDA is set to meet the requirement of approximately 97 to 98 percent of healthy individuals in a life-stage and sex group. It is derived from the estimated average requirement plus two standard deviations.

Question 15Food and Nutrition Science Knowledge

How do trans fatty acids affect blood lipids compared with the cis unsaturated fatty acids they replace?

  1. They have no measurable effect on blood lipids
  2. They lower LDL and raise HDL
  3. They raise LDL and lower HDL Correct answer.
  4. They raise HDL without affecting LDL

Explanation

Trans fats raise LDL cholesterol and lower HDL cholesterol, producing a more atherogenic profile than saturated fat at equal energy intake. This is why industrial trans fats have been largely removed from food supplies.

Question 16Food and Nutrition Science Knowledge

Periconceptional supplementation with which nutrient reduces the risk of neural tube defects?

  1. Iron
  2. Folate Correct answer.
  3. Calcium
  4. Vitamin B12

Explanation

Adequate folate around conception supports closure of the neural tube, and folic acid fortification and supplementation have documented preventive effects. The critical window is the first four weeks of gestation, often before pregnancy is recognized.

Question 17Food and Nutrition Science Knowledge

Which factor tends to lower the basal metabolic rate?

  1. Prolonged severe energy restriction Correct answer.
  2. Hyperthyroidism
  3. Fever
  4. A large amount of lean body mass

Explanation

Sustained severe energy restriction reduces basal metabolic rate through adaptive thermogenesis and loss of metabolically active tissue. Fever, hyperthyroidism and a high lean mass all raise resting energy expenditure.

Question 18Food and Nutrition Science Knowledge

A food is described as nutrient-dense when it provides which of the following?

  1. A large number of calories per gram
  2. A high proportion of saturated fat
  3. A large serving size per package
  4. A high nutrient content relative to its energy content Correct answer.

Explanation

Nutrient density expresses nutrients per unit of energy, so foods such as vegetables and legumes score highly. Energy-dense foods provide many calories with relatively few micronutrients.

Question 19Food and Nutrition Science Knowledge

The primary purpose of pasteurizing milk is to do which of the following?

  1. Destroy pathogenic microorganisms Correct answer.
  2. Completely sterilize the product
  3. Increase the vitamin content
  4. Improve calcium absorption

Explanation

Pasteurization applies a defined time-temperature combination sufficient to destroy pathogens such as Salmonella, Listeria and Escherichia coli O157:H7. It is not a sterilization process and does not make the product shelf-stable.

Question 20Food and Nutrition Science Knowledge

Which vitamin is synthesized in the skin after exposure to ultraviolet B radiation?

  1. Vitamin B6
  2. Vitamin D Correct answer.
  3. Vitamin A
  4. Vitamin K

Explanation

Ultraviolet B radiation converts 7-dehydrocholesterol in the epidermis to previtamin D3, which isomerizes to cholecalciferol. Subsequent hydroxylation in the liver and kidney produces the active hormone.

Question 21Food and Nutrition Science Knowledge

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) is obtained by which procedure?

  1. Subtracting the limiting amino acid content from crude protein
  2. Adding biological value to net protein utilization
  3. Multiplying the amino acid score by true fecal digestibility Correct answer.
  4. Dividing nitrogen intake by nitrogen excretion

Explanation

PDCAAS adjusts the amino acid score of a protein for its true fecal digestibility and truncates the result at 1.0. This corrects for the fact that some protein escapes digestion and is not available for synthesis.

Question 22Food and Nutrition Science Knowledge

A healthy adult is most likely to be in positive nitrogen balance during which circumstance?

  1. Active muscle wasting
  2. Pregnancy or growth Correct answer.
  3. Consumption of an energy-deficient diet
  4. An acute febrile illness

Explanation

Positive nitrogen balance means nitrogen intake exceeds excretion, reflecting net protein accretion as occurs in pregnancy, childhood growth and convalescence. Energy deficit, fever and wasting all promote net protein catabolism.

Question 23Food and Nutrition Science Knowledge

An indirect calorimetry measurement gives a respiratory quotient of 0.70. This value indicates that the predominant fuel being oxidized is which of the following?

  1. Fat Correct answer.
  2. Protein
  3. Carbohydrate
  4. A 50:50 carbohydrate-fat mix

Explanation

The respiratory quotient is carbon dioxide produced divided by oxygen consumed, and pure fat oxidation yields a value near 0.70. Carbohydrate oxidation approaches 1.00 and protein oxidation about 0.80, with mixed diets falling near 0.85.

Question 24Food and Nutrition Science Knowledge

Which statement best describes the physiological role of sodium?

  1. It is the principal intracellular cation
  2. It is the principal extracellular cation and maintains osmotic balance Correct answer.
  3. It is a cofactor for antioxidant enzymes
  4. It is the main structural mineral of bone

Explanation

Sodium is the dominant cation of extracellular fluid and, with chloride, determines plasma osmolality and volume. Potassium is the principal intracellular cation, and calcium and phosphorus form the mineral phase of bone.

Question 25Food and Nutrition Science Knowledge

Combining rice with beans improves overall protein quality because of which relationship?

  1. Cereal lysine complements legume methionine
  2. Legume lysine complements cereal methionine Correct answer.
  3. The combination raises the fat content of the meal
  4. Both foods are equally rich in lysine

Explanation

Legumes supply abundant lysine but are low in methionine, while cereals are low in lysine but contribute methionine. Eaten together they supply a complementary amino acid pattern closer to the reference protein.

Question 26Food and Nutrition Science Knowledge

Which macronutrient supplies approximately 9 kcal (about 37 kJ) per gram when metabolized?

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

Explanation

The Atwater factors assign roughly 9 kcal/g to fat, 4 kcal/g to protein and carbohydrate, and 7 kcal/g to alcohol. Fat's high energy density reflects the highly reduced state of its fatty acid chains.

Question 27Food and Nutrition Science Knowledge

Ascorbic acid acts as a cofactor in the post-translational modification of which structural protein?

  1. Collagen Correct answer.
  2. Ferritin
  3. Albumin
  4. Keratin

Explanation

Vitamin C is required by prolyl and lysyl hydroxylases, which hydroxylate collagen precursors so the triple helix can form stable cross-links. In scurvy, defective collagen causes bleeding gums, poor wound healing and capillary fragility.

Question 28Food and Nutrition Science Knowledge

Enlargement of the thyroid gland, or goiter, is most directly caused by a dietary deficiency of which mineral?

  1. Iron
  2. Iodine Correct answer.
  3. Zinc
  4. Selenium

Explanation

Iodine is a structural component of thyroxine and triiodothyronine. When intake is low, thyroid hormone output falls, TSH rises, and the gland hypertrophies in an attempt to trap more iodide.

Question 29Food and Nutrition Science Knowledge

Which dietary fiber acts mainly by adding bulk to the stool and shortening intestinal transit time?

  1. Pectin
  2. Cellulose Correct answer.
  3. Gum arabic
  4. Beta-glucan

Explanation

Cellulose is an insoluble, largely non-fermentable fiber that holds water within the colonic contents, increasing stool mass and accelerating transit. This is why wheat bran and other insoluble fibers relieve constipation.

Question 30Food and Nutrition Science Knowledge

Which fatty acid must be supplied by the diet because humans cannot synthesize it?

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

Explanation

Humans lack the desaturases needed to introduce double bonds beyond carbon 9, so linoleic acid (18:2 n-6) and alpha-linolenic acid (18:3 n-3) are indispensable. Linoleic acid is the predominant essential fatty acid in typical diets and is required for membrane phospholipids and eicosanoid precursors.

Question 31Food and Nutrition Science Knowledge

Calcium bioavailability is lowest from which of these foods?

  1. Spinach Correct answer.
  2. Cheddar cheese
  3. Milk
  4. Yogurt

Explanation

Spinach is rich in oxalic acid, which complexes calcium in the gut and renders most of it unabsorbable, so only a small fraction is taken up. Dairy foods lack such inhibitors and their calcium is absorbed far more efficiently.

Question 32Food and Nutrition Science Knowledge

Marasmus in young children is best characterized by which feature?

  1. Severe wasting without edema Correct answer.
  2. Hair depigmentation with skin rash
  3. Pitting edema with fatty liver
  4. Ascites with low serum albumin

Explanation

Marasmus reflects a chronic deficit of total energy, so the child catabolizes fat and muscle and presents with marked wasting, an old-looking face and no edema. Edema and an enlarged fatty liver belong to the protein-predominant picture of kwashiorkor.

Question 33Food and Nutrition Science Knowledge

Replacing dietary saturated fat with polyunsaturated fat characteristically produces which change in the lipid profile?

  1. Rise in LDL cholesterol
  2. Fall in HDL cholesterol
  3. Fall in LDL cholesterol Correct answer.
  4. No change in LDL cholesterol

Explanation

Substituting polyunsaturated for saturated fat lowers LDL cholesterol because saturated fatty acids down-regulate hepatic LDL receptor activity more than unsaturated ones do. The effect on HDL is small and inconsistent, so the LDL reduction is the characteristic outcome.

Question 34Food and Nutrition Science Knowledge

Commercial canning of low-acid foods destroys Clostridium botulinum spores mainly by which means?

  1. Curing with nitrite
  2. Retort heat sterilization Correct answer.
  3. Freezing at minus 20 degrees Celsius
  4. Drying to low water activity

Explanation

Botulinum spores are extremely heat resistant, so low-acid canned products receive a pressurized retort process (around 121 degrees Celsius) designed to deliver a large margin of spore inactivation. Because the sealed anaerobic can would otherwise permit outgrowth and toxin formation, this heat process is the critical control.

Question 35Food and Nutrition Science Knowledge

Beriberi, presenting with peripheral neuropathy and, in the wet form, heart failure, results from a deficiency of which vitamin?

  1. Riboflavin
  2. Pyridoxine
  3. Niacin
  4. Thiamin Correct answer.

Explanation

Thiamin pyrophosphate is a coenzyme for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and transketolase, so deficiency cripples carbohydrate oxidation in nerves and myocardium. This produces the classic dry (neuropathic) and wet (cardiovascular) forms of beriberi.

Question 36Food and Nutrition Science Knowledge

Efficient absorption of vitamin B12 in the ileum depends on which factor?

  1. Gastric lipase
  2. Bile salts
  3. Intrinsic factor Correct answer.
  4. Pancreatic trypsin

Explanation

Parietal cells secrete intrinsic factor, which binds dietary B12 and carries it to cubilin receptors on ileal enterocytes. Loss of intrinsic factor, as in pernicious anemia, causes B12 malabsorption regardless of dietary intake.

Question 37Food and Nutrition Science Knowledge

Increased dietary intake of which mineral has the strongest evidence for lowering blood pressure in adults?

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

Explanation

Potassium promotes natriuresis, relaxes vascular smooth muscle and blunts the pressor effect of a high sodium intake, which is why potassium-rich diets such as DASH lower blood pressure. Trials of supplemental potassium show consistent, modest reductions in systolic and diastolic pressure.

Question 38Food and Nutrition Science Knowledge

In the niacin equivalent system, how much dietary tryptophan corresponds to 1 mg of niacin?

  1. 6 mg
  2. 1 mg
  3. 60 mg Correct answer.
  4. 600 mg

Explanation

About 60 mg of dietary tryptophan is converted to 1 mg of niacin equivalent, so the requirement is expressed as niacin equivalents rather than preformed niacin alone. This conversion explains why maize-based diets, low in both available niacin and tryptophan, predispose to pellagra.

Question 39Food and Nutrition Science Knowledge

A toddler with phenylketonuria receives a phenylalanine-restricted formula. Which amino acid must be supplied generously because it becomes conditionally essential?

  1. Methionine
  2. Histidine
  3. Tyrosine Correct answer.
  4. Tryptophan

Explanation

Phenylalanine hydroxylase is deficient in phenylketonuria, so phenylalanine cannot be converted to tyrosine. Tyrosine therefore must be provided preformed in the diet to support protein synthesis, thyroid hormone and catecholamine production.

Question 40Food and Nutrition Science Knowledge

After glycogen stores are exhausted during a prolonged fast, which process chiefly supplies the brain's fuel?

  1. Hepatic ketogenesis from fatty acids Correct answer.
  2. Gluconeogenesis from free fatty acids
  3. Gluconeogenesis from muscle protein
  4. Direct neuronal oxidation of fatty acids

Explanation

Fatty acid carbons enter the liver as acetyl-CoA, which cannot be used for net glucose synthesis but can be converted to acetoacetate and beta-hydroxybutyrate. These ketone bodies cross the blood-brain barrier and replace glucose as the major cerebral fuel, sparing protein.

Question 41Nutrition Assessment

A patient weighs 70 kg and is 1.75 m tall. What is the patient's body mass index (BMI)?

  1. 25.7 kg/m²
  2. 22.9 kg/m² Correct answer.
  3. 18.5 kg/m²
  4. 40.0 kg/m²

Explanation

BMI is calculated as weight in kilograms divided by height in meters squared: 70 ÷ (1.75 × 1.75) = 22.9 kg/m², which falls within the normal range of 18.5–24.9 kg/m².

Question 42Nutrition Assessment

Which anthropometric measurement is the preferred index of central (intra-abdominal) adiposity?

  1. Mid-upper arm circumference
  2. Triceps skinfold thickness
  3. Waist circumference Correct answer.
  4. Calf circumference

Explanation

Waist circumference reflects visceral fat mass and is the recommended anthropometric indicator of central adiposity and associated cardiometabolic risk.

Question 43Nutrition Assessment

What is the principal limitation of a single 24-hour dietary recall?

  1. It cannot be administered to people who cannot read
  2. One day's intake may not represent usual intake and depends on memory Correct answer.
  3. It estimates habitual intake over the past year
  4. It requires that every food be weighed before consumption

Explanation

A 24-hour recall relies on the respondent's memory and captures only one day, so day-to-day variation means it often misrepresents habitual intake; repeated recalls improve accuracy.

Question 44Nutrition Assessment

A patient receives 12 g of nitrogen per day, and the 24-hour urinary urea nitrogen is 8 g. Using 4 g to account for miscellaneous losses, what is the nitrogen balance?

  1. −4 g
  2. +4 g
  3. +8 g
  4. 0 g (equilibrium) Correct answer.

Explanation

Nitrogen balance equals nitrogen intake minus (urinary urea nitrogen plus 4 g for obligatory non-urinary losses). Here 12 − (8 + 4) = 0 g, which indicates nitrogen equilibrium.

Question 45Nutrition Assessment

Which laboratory value is a negative acute-phase reactant, so that a low result may reflect inflammation rather than protein-energy depletion?

  1. C-reactive protein
  2. Serum albumin Correct answer.
  3. Serum ferritin
  4. Serum sodium

Explanation

Albumin is a negative acute-phase reactant: during inflammation the liver reprioritizes synthesis toward acute-phase proteins, so serum albumin falls independently of nutritional intake.

Question 46Nutrition Assessment

Bioelectrical impedance analysis estimates body composition by measuring which property?

  1. Absorption of near-infrared light by subcutaneous fat
  2. Attenuation of a low-energy X-ray beam by body tissues
  3. Impedance of a small alternating current through body water and tissues Correct answer.
  4. Volume of air displaced by the body in a closed chamber

Explanation

Bioelectrical impedance applies a small alternating current and measures resistance to it, which depends largely on total body water; fat-free mass is then estimated from that value.

Question 47Nutrition Assessment

Which technique is widely used as the reference standard for quantifying fat mass, lean mass, and bone mineral content?

  1. Skinfold thickness measurement
  2. Dual-energy X-ray absorptiometry Correct answer.
  3. Mid-upper arm circumference
  4. Bioelectrical impedance analysis

Explanation

Dual-energy X-ray absorptiometry separates fat, lean soft tissue, and bone mineral content with high precision and is used as the reference method in clinical body-composition research.

Question 48Nutrition Assessment

The triceps skinfold measurement is used to estimate which body compartment?

  1. Visceral adipose tissue
  2. Total fat-free mass
  3. Subcutaneous fat at the back of the upper arm Correct answer.
  4. Subcutaneous fat at the iliac crest

Explanation

The triceps skinfold is obtained with calipers over the posterior upper arm and provides an estimate of subcutaneous fat stores at that site.

Question 49Nutrition Assessment

Unintentional weight loss of what magnitude within one month is generally considered clinically significant?

  1. 2% in 1 month
  2. 3% in 6 months
  3. 5% in 1 month Correct answer.
  4. 1% in 6 months

Explanation

Loss of 5% or more of usual body weight in one month (about 7.5% in three months or 10% in six months) is considered clinically significant and warrants nutrition intervention.

Question 50Nutrition Assessment

Which predictive equation uses weight, height, age, and sex and is recommended for estimating resting energy expenditure in healthy adults?

  1. Friedewald equation
  2. Holliday-Segar method
  3. Cockcroft-Gault equation
  4. Mifflin-St Jeor equation Correct answer.

Explanation

The Mifflin-St Jeor equation incorporates weight, height, age, and sex and is recommended by the Academy of Nutrition and Dietetics as the most accurate predictive equation for resting energy expenditure in healthy adults.