DHN 101 Exam 2 Human Nutrition and
Wellness Official Practice Exam Actual
Exam 2026/2027 with Detailed Rationales |
Complete Exam-Style Questions | Pass
Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: METABOLISM & ENERGY BALANCE Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 28-year-old marathon runner visits a sports dietitian to optimize body composition for an
upcoming race. The dietitian explains that even at complete rest, his body requires a
substantial amount of energy to maintain vital organ function, body temperature, and cellular
processes. When calculating his total daily energy expenditure, which component typically
accounts for the largest percentage in a healthy adult?
A. The thermic effect of physical activity during training sessions
B. Basal metabolic rate sustained by lean tissue and organ mass ✓ CORRECT
C. The thermic effect of food from digesting high-protein meals
D. Adaptive thermogenesis responding to environmental temperature shifts
Correct Answer: B
Rationale: Basal metabolic rate represents the energy expended to maintain basic
physiological functions and typically comprises 60 to 75 percent of total daily energy
expenditure in most adults. The thermic effect of physical activity is highly variable and
usually represents 15 to 30 percent, while the thermic effect of food accounts for only about
10 percent of total expenditure. In clinical practice, estimating BMR using predictive
equations helps establish caloric targets before adding activity factors.
Question 2 of 50
A 45-year-old woman with obesity enrolls in a medically supervised weight-loss program. Her
registered dietitian calculates her estimated energy requirement and then designs a meal
plan that provides 500 kcal less than that value per day. The dietitian explains that this caloric
deficit will mobilize stored energy reserves to fuel metabolic processes. Which stored
substrate will be primarily mobilized to bridge this energy gap under normal conditions?
,A. Glycogen stored in skeletal muscle and hepatic tissue
B. Amino acids derived from structural muscle proteins
C. Triglycerides contained within adipose tissue depots
D. Fatty acids released from adipose lipolysis to produce ATP ✓ CORRECT
Correct Answer: D
Rationale: When dietary energy intake falls below expenditure, the body primarily mobilizes
fatty acids from adipose tissue triglycerides through hormone-sensitive lipase activity to
generate ATP via beta-oxidation. Glycogen stores are limited and depleted relatively quickly,
while significant protein catabolism is generally spared until fat reserves are substantially
reduced. This principle underlies why moderate caloric deficits preserve lean mass better
than severe restrictions.
Question 3 of 50
A clinical researcher is studying how different macronutrients influence postprandial energy
expenditure. She feeds participants three isocaloric test meals containing equivalent calories
but different macronutrient distributions and measures heat production for six hours after
ingestion. Which macronutrient is expected to produce the greatest increase in the thermic
effect of food?
A. Protein, due to the high energy cost of deamination and nitrogen disposal ✓ CORRECT
B. Carbohydrate, because of the extensive ATP required for glycogen synthesis
C. Fat, owing to the complex enzymatic steps of chylomicron formation
D. Alcohol, since hepatic detoxification demands substantial NAD+ regeneration
Correct Answer: A
Rationale: Dietary protein elicits the highest thermic effect of food, approximately 20 to 30
percent of its energy content, because amino acid catabolism, urea synthesis, and
gluconeogenesis are metabolically expensive processes. Carbohydrate and fat each produce
roughly 5 to 10 percent and 0 to 3 percent respectively, while alcohol also increases
thermogenesis but is not considered a macronutrient in standard metabolic calculations.
This metabolic reality supports higher protein intakes during weight loss to help maintain
energy expenditure.
Question 4 of 50
A second-year medical student is reviewing biochemistry and asks her nutrition professor
why the brain cannot rely on fatty acids for fuel during a 24-hour fast. The professor explains
that under normal fed conditions, the brain depends almost exclusively on one specific fuel
source, and that prolonged fasting triggers a metabolic shift to spare blood glucose for
obligate glucose users. Which metabolic pathway directly supplies the brain's preferred fuel
during the fed state?
, A. Beta-oxidation of fatty acids crossing the blood-brain barrier
B. Gluconeogenesis in the liver producing glucose from lactate
C. Glycolysis of circulating glucose followed by complete oxidation ✓ CORRECT
D. Ketogenesis in hepatic mitochondria generating soluble ketone bodies
Correct Answer: C
Rationale: Under fed and short-term fasting conditions, the brain primarily relies on glucose
supplied by the bloodstream, which undergoes glycolysis and subsequent oxidative
phosphorylation to meet its high ATP demands. Fatty acids cannot cross the blood-brain
barrier in appreciable amounts due to their reliance on albumin transport and the barrier's
lipid regulation, making direct oxidation impossible. Only after prolonged fasting does
ketogenesis provide an alternative fuel that readily crosses the barrier and spares glucose for
red blood cells and renal medulla.
Question 5 of 50
A 52-year-old man with a sedentary office job undergoes indirect calorimetry to determine his
resting metabolic rate. The test reveals a value lower than predicted by standard equations.
His body composition analysis shows elevated body fat percentage and reduced skeletal
muscle mass compared to age-matched norms. Which factor most likely explains his
lower-than-expected measured RMR?
A. The thermic effect of his low-fiber, processed-food diet is suppressing overall expenditure
B. Loss of metabolically active lean tissue has reduced his fasting energy needs ✓ CORRECT
C. Chronic mild dehydration from inadequate water intake is slowing cellular metabolism
D. His adipose tissue is actively uncoupling oxidative phosphorylation to generate heat
Correct Answer: B
Rationale: Resting metabolic rate is strongly correlated with the amount of metabolically
active lean tissue, particularly skeletal muscle and visceral organs, because these tissues
maintain ion gradients and protein turnover at high energy cost. Adipose tissue is far less
metabolically active per unit mass, so a shift toward higher fat mass and lower muscle mass
predictably depresses measured RMR. This is why resistance training is often recommended
during weight management to preserve the tissue that most heavily influences baseline
energy needs.
Question 6 of 50
A nutrition educator is explaining cellular energy metabolism to a group of nursing students.
She describes how acetyl-CoA enters a cyclic series of reactions in the mitochondrial matrix,
generating reduced coenzymes that ultimately drive oxidative phosphorylation. If a patient
has a thiamin deficiency affecting pyruvate dehydrogenase complex activity, which
downstream metabolic consequence would most directly impair ATP production from
glucose?
Wellness Official Practice Exam Actual
Exam 2026/2027 with Detailed Rationales |
Complete Exam-Style Questions | Pass
Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: METABOLISM & ENERGY BALANCE Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 28-year-old marathon runner visits a sports dietitian to optimize body composition for an
upcoming race. The dietitian explains that even at complete rest, his body requires a
substantial amount of energy to maintain vital organ function, body temperature, and cellular
processes. When calculating his total daily energy expenditure, which component typically
accounts for the largest percentage in a healthy adult?
A. The thermic effect of physical activity during training sessions
B. Basal metabolic rate sustained by lean tissue and organ mass ✓ CORRECT
C. The thermic effect of food from digesting high-protein meals
D. Adaptive thermogenesis responding to environmental temperature shifts
Correct Answer: B
Rationale: Basal metabolic rate represents the energy expended to maintain basic
physiological functions and typically comprises 60 to 75 percent of total daily energy
expenditure in most adults. The thermic effect of physical activity is highly variable and
usually represents 15 to 30 percent, while the thermic effect of food accounts for only about
10 percent of total expenditure. In clinical practice, estimating BMR using predictive
equations helps establish caloric targets before adding activity factors.
Question 2 of 50
A 45-year-old woman with obesity enrolls in a medically supervised weight-loss program. Her
registered dietitian calculates her estimated energy requirement and then designs a meal
plan that provides 500 kcal less than that value per day. The dietitian explains that this caloric
deficit will mobilize stored energy reserves to fuel metabolic processes. Which stored
substrate will be primarily mobilized to bridge this energy gap under normal conditions?
,A. Glycogen stored in skeletal muscle and hepatic tissue
B. Amino acids derived from structural muscle proteins
C. Triglycerides contained within adipose tissue depots
D. Fatty acids released from adipose lipolysis to produce ATP ✓ CORRECT
Correct Answer: D
Rationale: When dietary energy intake falls below expenditure, the body primarily mobilizes
fatty acids from adipose tissue triglycerides through hormone-sensitive lipase activity to
generate ATP via beta-oxidation. Glycogen stores are limited and depleted relatively quickly,
while significant protein catabolism is generally spared until fat reserves are substantially
reduced. This principle underlies why moderate caloric deficits preserve lean mass better
than severe restrictions.
Question 3 of 50
A clinical researcher is studying how different macronutrients influence postprandial energy
expenditure. She feeds participants three isocaloric test meals containing equivalent calories
but different macronutrient distributions and measures heat production for six hours after
ingestion. Which macronutrient is expected to produce the greatest increase in the thermic
effect of food?
A. Protein, due to the high energy cost of deamination and nitrogen disposal ✓ CORRECT
B. Carbohydrate, because of the extensive ATP required for glycogen synthesis
C. Fat, owing to the complex enzymatic steps of chylomicron formation
D. Alcohol, since hepatic detoxification demands substantial NAD+ regeneration
Correct Answer: A
Rationale: Dietary protein elicits the highest thermic effect of food, approximately 20 to 30
percent of its energy content, because amino acid catabolism, urea synthesis, and
gluconeogenesis are metabolically expensive processes. Carbohydrate and fat each produce
roughly 5 to 10 percent and 0 to 3 percent respectively, while alcohol also increases
thermogenesis but is not considered a macronutrient in standard metabolic calculations.
This metabolic reality supports higher protein intakes during weight loss to help maintain
energy expenditure.
Question 4 of 50
A second-year medical student is reviewing biochemistry and asks her nutrition professor
why the brain cannot rely on fatty acids for fuel during a 24-hour fast. The professor explains
that under normal fed conditions, the brain depends almost exclusively on one specific fuel
source, and that prolonged fasting triggers a metabolic shift to spare blood glucose for
obligate glucose users. Which metabolic pathway directly supplies the brain's preferred fuel
during the fed state?
, A. Beta-oxidation of fatty acids crossing the blood-brain barrier
B. Gluconeogenesis in the liver producing glucose from lactate
C. Glycolysis of circulating glucose followed by complete oxidation ✓ CORRECT
D. Ketogenesis in hepatic mitochondria generating soluble ketone bodies
Correct Answer: C
Rationale: Under fed and short-term fasting conditions, the brain primarily relies on glucose
supplied by the bloodstream, which undergoes glycolysis and subsequent oxidative
phosphorylation to meet its high ATP demands. Fatty acids cannot cross the blood-brain
barrier in appreciable amounts due to their reliance on albumin transport and the barrier's
lipid regulation, making direct oxidation impossible. Only after prolonged fasting does
ketogenesis provide an alternative fuel that readily crosses the barrier and spares glucose for
red blood cells and renal medulla.
Question 5 of 50
A 52-year-old man with a sedentary office job undergoes indirect calorimetry to determine his
resting metabolic rate. The test reveals a value lower than predicted by standard equations.
His body composition analysis shows elevated body fat percentage and reduced skeletal
muscle mass compared to age-matched norms. Which factor most likely explains his
lower-than-expected measured RMR?
A. The thermic effect of his low-fiber, processed-food diet is suppressing overall expenditure
B. Loss of metabolically active lean tissue has reduced his fasting energy needs ✓ CORRECT
C. Chronic mild dehydration from inadequate water intake is slowing cellular metabolism
D. His adipose tissue is actively uncoupling oxidative phosphorylation to generate heat
Correct Answer: B
Rationale: Resting metabolic rate is strongly correlated with the amount of metabolically
active lean tissue, particularly skeletal muscle and visceral organs, because these tissues
maintain ion gradients and protein turnover at high energy cost. Adipose tissue is far less
metabolically active per unit mass, so a shift toward higher fat mass and lower muscle mass
predictably depresses measured RMR. This is why resistance training is often recommended
during weight management to preserve the tissue that most heavily influences baseline
energy needs.
Question 6 of 50
A nutrition educator is explaining cellular energy metabolism to a group of nursing students.
She describes how acetyl-CoA enters a cyclic series of reactions in the mitochondrial matrix,
generating reduced coenzymes that ultimately drive oxidative phosphorylation. If a patient
has a thiamin deficiency affecting pyruvate dehydrogenase complex activity, which
downstream metabolic consequence would most directly impair ATP production from
glucose?
