,26/27 BIOL 121/BIOD 121 MODULE 1 EXAM |
NUTRITION / ESSENTIALS IN NUTRITION |
PORTAGE | Q&A + DETAILED RATIONALES
1 .A nutrition influencer claims that a powdered drink “detoxifies every organ within 48
hours,” provides only customer testimonials, and sells the product through the same
webpage. Which feature most strongly lowers the credibility of the claim?
A) The webpage discusses nutrition rather than medicine
B) The product is available without a prescription
C) Extraordinary health claims are presented without supporting scientific evidence while
the source has a financial interest
D) Consumers are allowed to post personal experiences
Correct Answer: Extraordinary health claims are presented without supporting scientific
evidence while the source has a financial interest
Rationale: A credible nutrition claim should be supported by appropriate scientific
evidence, disclose relevant conflicts of interest, and avoid promises that exceed the
available evidence. Testimonials cannot establish effectiveness because they lack controls
and cannot rule out coincidence, placebo effects, concurrent behavior changes, or selective
reporting. A source that both makes dramatic claims and profits directly from the
recommended product deserves particularly careful scrutiny. NIH guidance likewise
recommends examining a site's purpose, funding, evidence, and “too good to be true”
claims. (
2. During an online search, four pages discuss whether a particular dietary pattern lowers
cardiovascular risk. Which source provides the strongest starting point for evidence-
based evaluation?
A) A celebrity's personal account describing dramatic results
B) A recent systematic review of relevant human studies published in a peer-reviewed
scientific journal
C) A supplement company's article summarizing customer success stories
D) An anonymous social-media thread with thousands of likes
Correct Answer: A recent systematic review of relevant human studies published in a peer-
reviewed scientific journal
Rationale: A well-conducted systematic review uses an explicit method to identify and
evaluate multiple relevant studies, making it more informative than anecdotes or
promotional material. Peer review does not guarantee that conclusions are correct, but it
adds a layer of expert evaluation. The methodology, included studies, limitations, and
conflicts of interest should still be examined.
, 3. Researchers publish a nutrition study, but other independent research groups
repeatedly fail to reproduce the finding under comparable conditions. What
scientific principle is most directly challenged?
A) Energy balance
B) Nutrient density
C) Reproducibility of the finding
D) Dietary variety
Correct Answer: Reproducibility of the finding
Rationale: Reproducibility or replication helps determine whether an observation is robust
rather than the product of chance, unusual circumstances, or methodological problems. A
single study can generate an important hypothesis, but confidence normally grows when
independent evidence points in the same direction. Failure to reproduce a result does not
automatically prove the original finding false; it signals a need to investigate differences in
methods, populations, exposures, and statistical uncertainty.
4. Investigators hypothesize that replacing a sugary beverage with water will reduce
daily added-sugar intake. Which statement is the hypothesis?
A) Replacing the sugary beverage with water will reduce daily added-sugar intake
B) Participants will be recruited from a university
C) Added-sugar intake will be measured for four weeks
D) The results will be analyzed statistically
Correct Answer: Replacing the sugary beverage with water will reduce daily added-sugar
intake
Rationale: A hypothesis is a testable prediction about an expected relationship or effect.
Recruitment, measurement, and statistical analysis describe components of the study
method rather than the prediction itself. A useful hypothesis should be specific enough that
collected evidence could support or fail to support it.
5. An observational study finds that people who regularly eat breakfast report better
overall diet quality. Why would it be inappropriate to conclude from this result
alone that breakfast causes better diet quality?
A) Observational studies cannot collect information about food
B) Diet quality cannot be measured scientifically
C) Other characteristics of breakfast eaters may partly explain the association
D) Associations are meaningful only when the sample contains fewer than 100
participants
Correct Answer: Other characteristics of breakfast eaters may partly explain the
association
Rationale: Observational research can identify associations, but confounding variables
may contribute to them. For example, breakfast eaters could differ in socioeconomic
, circumstances, sleep patterns, physical activity, health awareness, or other dietary
behaviors. Consequently, correlation alone does not establish that changing breakfast
behavior would cause the observed difference in diet quality.
6. A researcher wants the strongest feasible design for testing whether one of two
dietary interventions causes a change in a measurable outcome. Which method
would generally provide the strongest causal evidence?
A) Asking participants which diet they already prefer
B) Comparing testimonials from followers of each diet
C) Measuring the diets of two self-selected social-media groups
D) Randomly assigning eligible participants to the two interventions
Correct Answer: Randomly assigning eligible participants to the two interventions
Rationale: Random assignment tends to distribute measured and unmeasured participant
characteristics more evenly between groups, reducing confounding and strengthening
causal inference. Nutrition trials can still have limitations involving adherence, blinding,
duration, attrition, and measurement error, so randomization is not an automatic
guarantee of validity. Nevertheless, randomized intervention designs are generally stronger
for causal questions than self-selected observational comparisons. (
7. Two groups in a dietary trial are treated identically except that one receives the
intervention being tested. What is the primary purpose of the comparison group?
A) To increase the calorie content of the intervention
B) To provide a reference for estimating the effect attributable to the intervention
C) To guarantee statistically significant results
D) To eliminate the need for randomization
Correct Answer: To provide a reference for estimating the effect attributable to the
intervention
Rationale: A comparison or control group helps researchers determine what would likely
have occurred without the intervention. Differences between the groups can then be
interpreted more meaningfully, assuming other important aspects of the study are
adequately controlled. A control group does not by itself prevent bias or guarantee
significance.
8. One nutrition survey includes 20 volunteers recruited from a competitive
bodybuilding club and is used to make conclusions about all U.S. adults. What is the
most important concern?
A) The survey contains too many participants
B) Bodybuilders cannot answer nutrition questions
C) Surveys are never useful in nutrition
D) The sample may not be representative of the population to which the conclusion
is being generalized
NUTRITION / ESSENTIALS IN NUTRITION |
PORTAGE | Q&A + DETAILED RATIONALES
1 .A nutrition influencer claims that a powdered drink “detoxifies every organ within 48
hours,” provides only customer testimonials, and sells the product through the same
webpage. Which feature most strongly lowers the credibility of the claim?
A) The webpage discusses nutrition rather than medicine
B) The product is available without a prescription
C) Extraordinary health claims are presented without supporting scientific evidence while
the source has a financial interest
D) Consumers are allowed to post personal experiences
Correct Answer: Extraordinary health claims are presented without supporting scientific
evidence while the source has a financial interest
Rationale: A credible nutrition claim should be supported by appropriate scientific
evidence, disclose relevant conflicts of interest, and avoid promises that exceed the
available evidence. Testimonials cannot establish effectiveness because they lack controls
and cannot rule out coincidence, placebo effects, concurrent behavior changes, or selective
reporting. A source that both makes dramatic claims and profits directly from the
recommended product deserves particularly careful scrutiny. NIH guidance likewise
recommends examining a site's purpose, funding, evidence, and “too good to be true”
claims. (
2. During an online search, four pages discuss whether a particular dietary pattern lowers
cardiovascular risk. Which source provides the strongest starting point for evidence-
based evaluation?
A) A celebrity's personal account describing dramatic results
B) A recent systematic review of relevant human studies published in a peer-reviewed
scientific journal
C) A supplement company's article summarizing customer success stories
D) An anonymous social-media thread with thousands of likes
Correct Answer: A recent systematic review of relevant human studies published in a peer-
reviewed scientific journal
Rationale: A well-conducted systematic review uses an explicit method to identify and
evaluate multiple relevant studies, making it more informative than anecdotes or
promotional material. Peer review does not guarantee that conclusions are correct, but it
adds a layer of expert evaluation. The methodology, included studies, limitations, and
conflicts of interest should still be examined.
, 3. Researchers publish a nutrition study, but other independent research groups
repeatedly fail to reproduce the finding under comparable conditions. What
scientific principle is most directly challenged?
A) Energy balance
B) Nutrient density
C) Reproducibility of the finding
D) Dietary variety
Correct Answer: Reproducibility of the finding
Rationale: Reproducibility or replication helps determine whether an observation is robust
rather than the product of chance, unusual circumstances, or methodological problems. A
single study can generate an important hypothesis, but confidence normally grows when
independent evidence points in the same direction. Failure to reproduce a result does not
automatically prove the original finding false; it signals a need to investigate differences in
methods, populations, exposures, and statistical uncertainty.
4. Investigators hypothesize that replacing a sugary beverage with water will reduce
daily added-sugar intake. Which statement is the hypothesis?
A) Replacing the sugary beverage with water will reduce daily added-sugar intake
B) Participants will be recruited from a university
C) Added-sugar intake will be measured for four weeks
D) The results will be analyzed statistically
Correct Answer: Replacing the sugary beverage with water will reduce daily added-sugar
intake
Rationale: A hypothesis is a testable prediction about an expected relationship or effect.
Recruitment, measurement, and statistical analysis describe components of the study
method rather than the prediction itself. A useful hypothesis should be specific enough that
collected evidence could support or fail to support it.
5. An observational study finds that people who regularly eat breakfast report better
overall diet quality. Why would it be inappropriate to conclude from this result
alone that breakfast causes better diet quality?
A) Observational studies cannot collect information about food
B) Diet quality cannot be measured scientifically
C) Other characteristics of breakfast eaters may partly explain the association
D) Associations are meaningful only when the sample contains fewer than 100
participants
Correct Answer: Other characteristics of breakfast eaters may partly explain the
association
Rationale: Observational research can identify associations, but confounding variables
may contribute to them. For example, breakfast eaters could differ in socioeconomic
, circumstances, sleep patterns, physical activity, health awareness, or other dietary
behaviors. Consequently, correlation alone does not establish that changing breakfast
behavior would cause the observed difference in diet quality.
6. A researcher wants the strongest feasible design for testing whether one of two
dietary interventions causes a change in a measurable outcome. Which method
would generally provide the strongest causal evidence?
A) Asking participants which diet they already prefer
B) Comparing testimonials from followers of each diet
C) Measuring the diets of two self-selected social-media groups
D) Randomly assigning eligible participants to the two interventions
Correct Answer: Randomly assigning eligible participants to the two interventions
Rationale: Random assignment tends to distribute measured and unmeasured participant
characteristics more evenly between groups, reducing confounding and strengthening
causal inference. Nutrition trials can still have limitations involving adherence, blinding,
duration, attrition, and measurement error, so randomization is not an automatic
guarantee of validity. Nevertheless, randomized intervention designs are generally stronger
for causal questions than self-selected observational comparisons. (
7. Two groups in a dietary trial are treated identically except that one receives the
intervention being tested. What is the primary purpose of the comparison group?
A) To increase the calorie content of the intervention
B) To provide a reference for estimating the effect attributable to the intervention
C) To guarantee statistically significant results
D) To eliminate the need for randomization
Correct Answer: To provide a reference for estimating the effect attributable to the
intervention
Rationale: A comparison or control group helps researchers determine what would likely
have occurred without the intervention. Differences between the groups can then be
interpreted more meaningfully, assuming other important aspects of the study are
adequately controlled. A control group does not by itself prevent bias or guarantee
significance.
8. One nutrition survey includes 20 volunteers recruited from a competitive
bodybuilding club and is used to make conclusions about all U.S. adults. What is the
most important concern?
A) The survey contains too many participants
B) Bodybuilders cannot answer nutrition questions
C) Surveys are never useful in nutrition
D) The sample may not be representative of the population to which the conclusion
is being generalized
