Evidence-Based Nutrition and Practice Flashcards
A method of attempting to arrive at objective truths.
Science
A proposed explanation for a problem or set of observations.
Hypothesis
The process of formulating explanations about the natural world and testing those explanations with experiments and data.
The Scientific Method
A three-pronged approach to working with clients, which consists of making decisions based on the weight of the scientific evidence, field observations, and individual client needs and preferences.
Evidence-Based Practice
What are the three components of evidence-based practice?
- Weight of evidence
- Field observations
- Client needs and preferences
Describe the Scientific Method.
- Identify a problem or set of observations.
- Formulate a hypothesis.
- Design a study to test the hypothesis.
- Collect, synthesize, and interpret data.
- Discard/change the hypothesis if the data does not support it, OR continue testing data that supports the hypothesis.
An expected outcome generated from a hypothesis.
Prediction
Things that should be true if a hypothesis is true.
Predictions
Step 1 of the Scientific Method
Identify a problem or set of observations.
Step 2 of the Scientific Method
Formulate a hypothesis
Step 3 of the Scientific Method
Design a study to test the hypothesis.
Step 4 of the Scientific Method
Collect data, synthesize it, and interpret it.
Step 5 of the Scientific Method
Discard unsupported hypothesis or continue testing supported hypotheses.
True or False? Scientists identify what is most likely to be true by demonstrating what is NOT true.
True
A hypothesis or set of hypotheses for which a large body of high-quality evidence has been accumulated.
Theory
A variable in an experiment that a scientist makes no effort to manipulate or account for.
Uncontrolled variable
What is a peer-reviewed editorial?
An opinion piece in a scientific journal.
What is an expert opinion?
Represents the stance of scientists who have extensively studied a topic.
This type of evidence represents the stance of scientists who have extensively studied a topic.
Expert opinion
What is an opinion piece in a scientific journal called?
Peer-reviewed editorial
Research in which a researcher observes ongoing behaviors to determine correlation.
Observational Research
A relationship between two or more variables.
Correlation
What type of research can only show correlations?
Observational Research
What is a 24 hour recall?
When subjects try to recall what they ate over the past day
Subjects list the frequency with which they consume various food categories
Food Frequency Questionnaire
A type of scientific study/trial where participants are randomly assigned into different groups – one or more will be the intervention to be tested and one will be the control group. Groups are randomized and a control is used in an attempt to reduce potential bias in the trial.
Randomized Control Trial (RCT)
What is a Randomized Control Trial?
A type of scientific study/trial where participants are randomly assigned into different groups. Some groups will be the intervention that is tested, and one will be the control group.
The variable scientists manipulate in an experiment.
Independent variable
What is an independent variable?
The variable scientists manipulate in an experiment.
The ability to generalize the results of a study.
External validity
What is external validity?
The ability to generalize the results of a study.
A review where scientists systematically gather all research on a topic and evaluate it based on predefined criteria and rules.
Systematic Review
What is a systematic review?
Scientists gather ALL research on a topic and evaluate it based on specific criteria.
A statistical analysis of a group of studies to assess the overall weight of the evidence.
Meta-analysis
What is a meta-analysis?
A statistical analysis of a group of studies (RCT’s).
What two things represent the highest level of quality of evidence?
Systematic reviews and meta-analyses.
True or False? A scientific theory is just a guess.
False.
Which of the following ranks highest in terms of quality?
A. Observational research
B. Non-peer reviewed media
C. Randomized control trials
D. Peer-reviewed editorials
C. Randomized control trials
Type of evidence based on observation or experience.
Empirical evidence.
What is empirical evidence?
Type of evidence based on observation or experience
The ability to get similar results when something is measured under the same conditions.
Test-retest reliability
The consistency of a measure.
Reliability
The assessment of whether a tool is measuring what it is supposed to measure.
Validity
When a sample of people under study is not representative of the larger population that scientists are looking to make inferences about, this is known as ______.
Selection Bias
Describes a study that looks backward in time.
Retrospective
The inability to accurately remember past behaviors.
Recall bias
What type of research are case studies, surveys, and historical research?
Descriptive Research
What is descriptive research?
Describes individuals or populations.
Example: case studies, surveys, historical research
• Tracks a single person or group of people
over time
• Discusses characteristics of or events that
occur to a single person or group
• Primary limitation - may not be
generalizable to larger populations
Case studies
What is a case study?
• Tracks a single person or group of people
over time
• Discusses characteristics of or events that
occur to a single person or group
What is the primary limitation of a case study?
May not be generalizable to larger populations
What type of research are cross-sectional studies, case-control studies, and cohort studies?
Exploratory/Epidemiological Research
What is a cross-sectional study?
Variables in group of people at specific point in time
What are cross-sectional studies most useful for?
- Population-based surveys
* To assess the prevalence of diseases in a population
What is the primary limitation of a cross-sectional study?
Impossible to assess causal relationships because it’s a one-time “snapshot” measurement
What is a case-control study?
- Determines if exposure to something is associated with an outcome
- Scientists identify people with the outcome and similar people who don’t have the outcome
- Uses data that has already been collected or occurred in the past
What type of study is this? • Determines if exposure to something is associated with an outcome • Scientists identify people with the outcome and similar people who don’t have the outcome • Uses data that has already been collected or occurred in the past
Case-control study
What is a cohort study?
Group followed over time to find association between exposure & outcome (e.g., disease)
What kind of study is this: Group followed over time to determine association between an exposure and an outcome or disease?
Cohort study
What are the limitations of a cohort study?
- Selection bias possibility
- Subjects may drop out because the study is so long
- If retrospective: less control over variables; subjects may have recall bias
What are the two types of observational research?
Descriptive research and Exploratory Research.
What type of research are cohort studies, cross-sectional studies, case studies, and surveys?
Observational research
Type of study in which scientists directly intervene with subjects and look at the impacts of the intervention
Interventional Design study
Type of study in which researchers track two or more independent groups in parallel with each other.
Parallel Design study
Type of study in which researchers test the impact of two or more variables simultaneously, rather than isolating a single variable.
Factorial Design Study
Type of study in which the same group of subjects are assigned to both the treatment and control groups. Each subject acts as his/her own control.
Crossover Design Study
A type of scientific research design that consists of Randomized Controlled Trials (RCTs), which are the “gold standard” of research due to degree of rigor and control.
True Experimental Design
A type of scientific research design that is similar to RCTs, but subjects are not randomly assigned to groups.
Quasi-experimental design
What are two examples of Quasi-experimental design?
Non-randomized control group and time series.
Non-randomized control group and time series are examples of what kind of experimental design?
Quasi-experimental design
A type of research design in which subjects have not been randomly assigned to that group. This carries more potential for bias than a RCT, because the control group may not be equivalent to the treatment group.
Non-randomized control group
A type of research design in which a set of data points have been collected in time order.
Time Series
The critical evaluation of a study by other scientists.
Peer review
Types of peer-review of thorough and valuable summations of the state of the evidence on various topics. They are usually written by large teams of scientists.
Position stands and scientific consensus statements
A type of peer-reviewed journal article in which research is gathered in a more informal fashion compared to a systematic review and the authors give their assessment and interpretation of the overall weight of the evidence.
Narrative review
What are these examples of?
Recently published academic textbooks
University public health websites
Academy of Nutrition and Dietetics website
U.S. government health websites
International health websites
Conference presentations by primary researchers without a brand or ideology to defend or product or supplement to promote
Podcast interviews with primary researchers
High-Quality, Non-Peer Reviewed Sources of Information
What are these examples of? Popular media. Anecdotes and testimonials. Advertisements of products or special methods and protocols Most blogs (and their comment sections)
Questionable or Poor, Non-Peer Reviewed Sources of Information
Which of the following represents a weakness of observational studies?
A . Examination of large populations over long periods of time
B . Generation of hypotheses for further study
C . Examination of associations over long periods of time
D . Correlation does not equal causation
D . Correlation does not equal causation
Which of the following best represents a weakness of interventional designs?
A Small number of subjects
B Demonstration of cause and effect
C Exploration of mechanistic explanations
D Control of variables that can’t be controlled in observational studies
A Small number of subjects
Scientists randomly assign subjects to a low or high carbohydrate group and then look at changes in body weight over 3 months. Which item represents the independent variable in this study?
A. Length of study (3 months)
B. Subjects
C. Body weight
D. Diet type
D. Diet type
Which term describes how a body of knowledge is based on observation and experience?
A. Repeatable
B. Falsifiable
C. Reliable
D. Empirical
D. Empirical
Studies show that Diet A causes more weight loss than Diet B. A client is able to better adhere to Diet B than Diet A. Which item represents the best option for this client?
A Start with Diet A, then gradually transition to Diet B
B. Diet B
C. Alternate between Diet A and B
D. Diet A
B. Diet B
Seven studies show Diet A lowers cholesterol more than Diet B. Three studies show no difference. Assuming all the studies are equivalent in quality, which item best describes this situation?
A. There are insufficient studies to conclude that Diet A lowers cholesterol more than Diet B.
B. The weight of the evidence suggests Diet A is more effective for lowering cholesterol than Diet B, but more data is needed.
C. The weight of the evidence suggests that Diet A and B are equivalent in their ability to lower cholesterol.
D. It is unknown whether Diet A lowers cholesterol more than Diet B.
B. The weight of the evidence suggests Diet A is more effective for lowering cholesterol than Diet B, but more data is needed.
Scientists gather 20 studies looking at the relationship between protein intake and lean body mass, and then they statistically analyze them together as a group. What type of study is this?
A. Randomized controlled trials
B. Observational research
C. Meta-analysis
D. Narrative review
C. Meta-analysis
Which term encompasses the weight of the scientific evidence, field observations, and individual client needs?
A. Science
B. Evidence-based practice
C. Scientific method
D. Primary research
B. Evidence-based practice
Which item represents a high quality, non-peer reviewed source of information?
A. Academic textbook
B. Position stand
C. Systematic review
D. Narrative review
A. Academic textbook
Which of the following represents a strength of observational studies?
A. Large subject numbers
B. Can establish cause and effect
C. Can determine mechanisms for effects
D. High degree of control
A. Large subject numbers
Scientists perform a study tracking 10,000 people over a 10-year period. They look at their sugar intake at the beginning of the study and then see who develops diabetes over the study duration. Which term best describes this study?
A. Cohort study
B. Cross-sectional study
C. Survey
D. Case-control study
A. Cohort study
Which statement best describes science?
A. It is the use of evidence to construct explanations and predictions of natural phenomena.
B. It is the process of collecting data that confirms a hypothesis while discarding data that refutes it.
C. It is the collection of ideas that are not subject to falsification.
D. It is the use of anecdotes to explain observations.
A. It is the use of evidence to construct explanations and predictions of natural phenomena.
A scientist proposes that sugar is inherently fattening, independent of its calorie content. If that proposal is true, then that would mean that high-sugar diets should increase fat gain independent of their calorie content. What term describes this potential consequence?
A. Theory
B. Hypothesis
C. Prediction
D. Conclusion
C. Prediction
A scientist hypothesizes that a supplement will increase resistance training performance. A study is carried out, and the results do not support the hypothesis. Multiple studies by independent labs also fail to support the hypothesis. What is the appropriate response regarding the hypothesis?
A. The predictions have been falsified and the hypothesis is discarded.
B. The hypothesis should continue to be tested.
C. The predictions have been confirmed but the hypothesis is discarded.
D. The predictions have been falsified but the hypothesis is upheld.
A. The predictions have been falsified and the hypothesis is discarded.
