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WGU D440 Nutrition OA 2026/2027 – Complete
Study Guide | Must-Know Questions and
Answers + Proven Tips to Pass on Your First Try |
Updated for Newest WGU Objective Assessment |
Pass Guaranteed - A+ Graded
Section 1: D440 Nutrition Objective Assessment
STUDY TIP: Focus on understanding the chemical structure and physiological functions of
macronutrients. Remember that carbohydrates, proteins, and lipids each serve unique roles in
energy provision and metabolic processes.
Q1: Which monosaccharide is the primary source of energy for the brain and red blood cells?
A. Fructose
B. Galactose
C. Glucose [CORRECT]
D. Ribose
Correct Answer: C
Rationale: Glucose is the preferred energy source for the brain and red blood cells because it can
cross the blood-brain barrier and is the only fuel source that red blood cells can utilize due to
their lack of mitochondria.
Q2: A patient consumes a meal containing 60 grams of carbohydrate. How many kilocalories
does this contribute to their total energy intake?
A. 120 kcal
B. 180 kcal
C. 240 kcal [CORRECT]
D. 300 kcal
Correct Answer: C
Rationale: Carbohydrates provide 4 kcal per gram; therefore, 60 grams × 4 kcal/gram = 240
kilocalories.
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,2
Q3: Which type of fiber dissolves in water to form a gel-like substance that helps lower blood
cholesterol levels?
A. Cellulose
B. Hemicellulose
C. Soluble fiber [CORRECT]
D. Insoluble fiber
Correct Answer: C
Rationale: Soluble fiber (found in oats, beans, and apples) dissolves in water to form viscous gels
that bind bile acids and cholesterol, facilitating their excretion and thereby lowering blood
cholesterol levels.
Q4: What is the Acceptable Macronutrient Distribution Range (AMDR) for carbohydrates as a
percentage of total daily calories?
A. 20-35%
B. 10-35%
C. 45-65% [CORRECT]
D. 55-75%
Correct Answer: C
Rationale: The AMDR for carbohydrates is 45-65% of total daily caloric intake, ensuring
adequate glucose for brain function and energy while allowing flexibility for individual needs.
Q5: Which polysaccharide serves as the storage form of glucose in humans and animals?
A. Cellulose
B. Starch
C. Glycogen [CORRECT]
D. Chitin
Correct Answer: C
Rationale: Glycogen is the storage form of glucose in animals and humans, primarily stored in
the liver and skeletal muscles, and can be rapidly broken down to maintain blood glucose levels
during fasting.
Q6: Which enzyme is responsible for the initial digestion of carbohydrates in the mouth?
2
,3
A. Pancreatic amylase
B. Maltase
C. Salivary amylase [CORRECT]
D. Sucrase
Correct Answer: C
Rationale: Salivary amylase (ptyalin) begins carbohydrate digestion in the mouth by hydrolyzing
starch into smaller polysaccharides and maltose; this enzyme is inactivated by stomach acid.
STUDY TIP: Remember that proteins are the only macronutrient containing nitrogen. The
nitrogen balance (intake vs. excretion) indicates whether the body is building or breaking down
protein tissue.
Q7: How many essential amino acids must be obtained from the diet in humans?
A. 6
B. 9 [CORRECT]
C. 12
D. 20
Correct Answer: B
Rationale: There are nine essential amino acids (histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, threonine, tryptophan, and valine) that cannot be synthesized by the body and
must be obtained from dietary protein sources.
Q8: Which protein quality assessment method is currently recognized by the FDA and WHO as
the preferred standard?
A. Biological value
B. Protein efficiency ratio
C. PDCAAS (Protein Digestibility Corrected Amino Acid Score) [CORRECT]
D. Net protein utilization
Correct Answer: C
Rationale: PDCAAS is the internationally recognized method for evaluating protein quality,
comparing the amino acid profile of a food to human requirements and correcting for
digestibility, with values capped at 1.0 (100%).
Q9: What is the AMDR for protein as a percentage of total daily calories?
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, 4
A. 5-15%
B. 10-35% [CORRECT]
C. 20-40%
D. 25-45%
Correct Answer: B
Rationale: The AMDR for protein is 10-35% of total daily calories, providing adequate amino
acids for tissue maintenance, enzyme synthesis, and immune function while preventing excessive
intake.
Q10: A patient requires 2000 kcal per day. What is the minimum recommended protein intake in
grams based on the RDA of 0.8 g/kg for a 70 kg adult?
A. 40 grams
B. 56 grams [CORRECT]
C. 70 grams
D. 100 grams
Correct Answer: B
Rationale: The RDA for protein is 0.8 grams per kilogram of body weight; for a 70 kg adult, this
equals 56 grams of protein per day (70 kg × 0.8 g/kg = 56 g).
Q11: Which condition results from a deficiency of the essential amino acid phenylalanine
metabolism?
A. Cystic fibrosis
B. Phenylketonuria (PKU) [CORRECT]
C. Celiac disease
D. Maple syrup urine disease
Correct Answer: B
Rationale: PKU is an inherited disorder characterized by inability to metabolize phenylalanine
due to deficiency of the enzyme phenylalanine hydroxylase, requiring a phenylalanine-restricted
diet to prevent intellectual disability.
Q12: During protein digestion, which enzyme breaks down polypeptides into smaller peptides in
the stomach?
A. Trypsin
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WGU D440 Nutrition OA 2026/2027 – Complete
Study Guide | Must-Know Questions and
Answers + Proven Tips to Pass on Your First Try |
Updated for Newest WGU Objective Assessment |
Pass Guaranteed - A+ Graded
Section 1: D440 Nutrition Objective Assessment
STUDY TIP: Focus on understanding the chemical structure and physiological functions of
macronutrients. Remember that carbohydrates, proteins, and lipids each serve unique roles in
energy provision and metabolic processes.
Q1: Which monosaccharide is the primary source of energy for the brain and red blood cells?
A. Fructose
B. Galactose
C. Glucose [CORRECT]
D. Ribose
Correct Answer: C
Rationale: Glucose is the preferred energy source for the brain and red blood cells because it can
cross the blood-brain barrier and is the only fuel source that red blood cells can utilize due to
their lack of mitochondria.
Q2: A patient consumes a meal containing 60 grams of carbohydrate. How many kilocalories
does this contribute to their total energy intake?
A. 120 kcal
B. 180 kcal
C. 240 kcal [CORRECT]
D. 300 kcal
Correct Answer: C
Rationale: Carbohydrates provide 4 kcal per gram; therefore, 60 grams × 4 kcal/gram = 240
kilocalories.
1
,2
Q3: Which type of fiber dissolves in water to form a gel-like substance that helps lower blood
cholesterol levels?
A. Cellulose
B. Hemicellulose
C. Soluble fiber [CORRECT]
D. Insoluble fiber
Correct Answer: C
Rationale: Soluble fiber (found in oats, beans, and apples) dissolves in water to form viscous gels
that bind bile acids and cholesterol, facilitating their excretion and thereby lowering blood
cholesterol levels.
Q4: What is the Acceptable Macronutrient Distribution Range (AMDR) for carbohydrates as a
percentage of total daily calories?
A. 20-35%
B. 10-35%
C. 45-65% [CORRECT]
D. 55-75%
Correct Answer: C
Rationale: The AMDR for carbohydrates is 45-65% of total daily caloric intake, ensuring
adequate glucose for brain function and energy while allowing flexibility for individual needs.
Q5: Which polysaccharide serves as the storage form of glucose in humans and animals?
A. Cellulose
B. Starch
C. Glycogen [CORRECT]
D. Chitin
Correct Answer: C
Rationale: Glycogen is the storage form of glucose in animals and humans, primarily stored in
the liver and skeletal muscles, and can be rapidly broken down to maintain blood glucose levels
during fasting.
Q6: Which enzyme is responsible for the initial digestion of carbohydrates in the mouth?
2
,3
A. Pancreatic amylase
B. Maltase
C. Salivary amylase [CORRECT]
D. Sucrase
Correct Answer: C
Rationale: Salivary amylase (ptyalin) begins carbohydrate digestion in the mouth by hydrolyzing
starch into smaller polysaccharides and maltose; this enzyme is inactivated by stomach acid.
STUDY TIP: Remember that proteins are the only macronutrient containing nitrogen. The
nitrogen balance (intake vs. excretion) indicates whether the body is building or breaking down
protein tissue.
Q7: How many essential amino acids must be obtained from the diet in humans?
A. 6
B. 9 [CORRECT]
C. 12
D. 20
Correct Answer: B
Rationale: There are nine essential amino acids (histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, threonine, tryptophan, and valine) that cannot be synthesized by the body and
must be obtained from dietary protein sources.
Q8: Which protein quality assessment method is currently recognized by the FDA and WHO as
the preferred standard?
A. Biological value
B. Protein efficiency ratio
C. PDCAAS (Protein Digestibility Corrected Amino Acid Score) [CORRECT]
D. Net protein utilization
Correct Answer: C
Rationale: PDCAAS is the internationally recognized method for evaluating protein quality,
comparing the amino acid profile of a food to human requirements and correcting for
digestibility, with values capped at 1.0 (100%).
Q9: What is the AMDR for protein as a percentage of total daily calories?
3
, 4
A. 5-15%
B. 10-35% [CORRECT]
C. 20-40%
D. 25-45%
Correct Answer: B
Rationale: The AMDR for protein is 10-35% of total daily calories, providing adequate amino
acids for tissue maintenance, enzyme synthesis, and immune function while preventing excessive
intake.
Q10: A patient requires 2000 kcal per day. What is the minimum recommended protein intake in
grams based on the RDA of 0.8 g/kg for a 70 kg adult?
A. 40 grams
B. 56 grams [CORRECT]
C. 70 grams
D. 100 grams
Correct Answer: B
Rationale: The RDA for protein is 0.8 grams per kilogram of body weight; for a 70 kg adult, this
equals 56 grams of protein per day (70 kg × 0.8 g/kg = 56 g).
Q11: Which condition results from a deficiency of the essential amino acid phenylalanine
metabolism?
A. Cystic fibrosis
B. Phenylketonuria (PKU) [CORRECT]
C. Celiac disease
D. Maple syrup urine disease
Correct Answer: B
Rationale: PKU is an inherited disorder characterized by inability to metabolize phenylalanine
due to deficiency of the enzyme phenylalanine hydroxylase, requiring a phenylalanine-restricted
diet to prevent intellectual disability.
Q12: During protein digestion, which enzyme breaks down polypeptides into smaller peptides in
the stomach?
A. Trypsin
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