Chapter 3: Evidence-Based Nutrition and Practice

Question 1

A proposed explanation for a problem or set of observations.

Answer 1

Hypothesis

Question 2

The process of formulating explanations about the natural world and testing those explanations with experiments and data.

Answer 2

The Scientific Method

Question 3

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.

Answer 3

Evidence-Based Practice

Question 4

Steps of the Scientific Method

Answer 4

1: Identify a problem or set of observations
2: Formulate a hypothesis
3: Design a study to test the hypothesis
4: Collect, synthesize, and interpret data
5: Discard or change hypothesis if data doesn’t support it OR continue testing data that supports the hypothesis.

Question 5

An expected outcome generated from a hypothesis.

Answer 5

Prediction

Question 6

True or False: Scientists identify what is most likely to be true by demonstrating what is not true.

Answer 6

True

Question 7

A hypothesis or set of hypotheses for which a large body of high-quality evidence has been accumulated.

Answer 7

Theory

Question 8

An account of a person’s experience or event.

Answer 8

Anecdote

Question 9

A variable in an experiment that a scientist makes no effort to manipulate or account for.

Answer 9

Uncontrolled Variable

Question 10

Original research where scientists perform experiments and collect data – this is in contrast to secondary research where scientists analyze data that has already been collected or published elsewhere.

Answer 10

Primary Research

Question 11

Research in which a researcher observes ongoing behaviors to determine correlation.

Answer 11

Observational Research

Question 12

A relationship between two or more variables.

Answer 12

Correlation

Question 13

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.

Answer 13

Randomized Control Trial (RCT)

Question 14

The variable scientists manipulate in an experiment.

Answer 14

Independent Variable

Question 15

The ability to generalize the results of a study.

Answer 15

External Validity

Question 16

A review where scientists systematically gather all research on a topic and evaluate it based on predefined criteria and rules.

Answer 16

Systematic Review

Question 17

A statistical analysis of a group of studies to assess the overall weight of the evidence. It is an analysis of RCTs.

Answer 17

Meta-Analysis

Question 18

What 2 reviews represent the highest evidence level because they give the consensus on the best research.

Answer 18

Meta-analysis (RCTs) and systematic review

Question 19

True or False: A scientific theory is just a guess.

Answer 19

False

Question 20

The scientific approach is _______ which means it is based on observation or experience.

Answer 20

Empirical

Question 21

Case Studies, Surveys, Historical Research

Answer 21

3 Types of Descriptive Scientific Research

Question 22

Cross-Sectional Studies, Case-control Studies, Cohort Studies

Answer 22

3 Types of Exploratory or Epidemiological Scientific Research

Question 23

• Track a single person or group of people
over time
• Discuss characteristics of or events that
occur to a single person or group
• Primary limitation - may not be
generalizable to larger populations

Answer 23

Case Studies

Question 24

• Questionnaires or interviews administered
 to samples of people
• Primary limitation:
 • They collect self-reported data, and
 can be subject to bias
 • Potential issues with the reliability,
 validity, or how wording of questions
 can influence people’s answers

Answer 24

Surveys

Question 25

Historical Research

Answer 25

``` • Looks at events that happened in the past and uses it to make inferences about other times, including the future • Limitations: • Information from the past may be incomplete or inaccessible • May be subject to the biases of the researchers involved ```

Question 26

• Variables in a group at a specific point in time • A cross-section of people • Most useful for: • Population-based surveys • To assess the prevalence of diseases in a population • Primary limitation - impossible to assess causal relationships because it’s a one-time “snapshot” measurement

Answer 26

Cross-sectional Studies

Question 27

• Determine 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

Answer 27

Case-control Studies

Question 28

Group followed over time to determine association between an exposure and an outcome or disease 1. Cohort free of outcome or disease 2. Researchers identify exposure or event of interest 3. Cohort followed over time until disease or outcome occurs 4. Association between exposure and risk of outcome assessed • Limitations: • Susceptibility to selection bias • Subjects are followed for extended periods of time may withdraw or be lost follow-up • If retrospective: less control over variables, and that subjects may be susceptible to recall bias

Answer 28

Cohort Studies

Question 29

A sample of people under study is not representative of the larger population that scientists are looking to make inferences about.

Answer 29

Selection Bias

Question 30

The critical evaluation of a study by other scientists. This is the highest quality source of scientific info.

Answer 30

Peer Review

Question 31

Which of the following best describes an empirical scientific approach?

Answer 31

Controlled observation

Question 32

Which of the following represents a weakness of observational studies?

Answer 32

Correlation does not equal causation

Question 33

Which of the following best represents a weakness of interventional designs?

Answer 33

Small number of subjects

Question 34

Scientists perform a study looking at the effects of caffeine on vertical jump performance. On one day, they give all the subjects caffeine followed by vertical jump tests. Two weeks later, they give all the subjects a placebo followed by the same vertical jump tests. Which term best describes this study design?

Answer 34

Crossover

Question 35

Which item represents a high quality, non-peer reviewed source of information?

Answer 35

Academic Textbook

Question 36

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?

Answer 36

The predictions have been falsified and the hypothesis is discarded.

Question 37

Which term encompasses the weight of the scientific evidence, field observations, and individual client needs?

Answer 37

Evidence-based practice

Question 38

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?

Answer 38

Diet type

Question 39

Numerous studies, including genetic studies, randomized controlled trials on lipid lowering medications, and observational studies point to LDL having a causal role in heart disease. Which term best describes the concept that LDL plays a causal role in heart disease?

Answer 39

Theory

Question 40

Scientists take 5000 people and have them fill out questionnaires on their dairy intake. They then compare cancer rates between people with high intakes and low intakes. What type of study is this?

Answer 40

Observational

Question 41

Which of the following represents a strength of observational studies?

Answer 41

Large subject numbers

Question 42

Scientists perform a study comparing 1000 women with breast cancer to 1000 women without breast cancer. They gather information on the women's diets and look to see if the women diagnosed with breast cancer had more fat in their diet compared to the women who did not get cancer. Which term best describes this study?

Answer 42

Case-control study

Question 43

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?

Answer 43

Meta-analysis

Question 44

Which term describes a variable in an experiment for which a scientist takes no steps to account for?

Answer 44

Uncontrolled variable

Question 45

Scientists find that a protein supplement increases lean mass in the elderly. However, they caution that the results may not apply to other populations, like younger people. What term best describes what the scientists are referring to?

Answer 45

External validity

Question 46

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?

Answer 46

Cohort

Question 47

Which term describes the phenomena when a group does not represent the population a scientist is intending to study?

Answer 47

Selection bias

Question 48

A scientist observes that people tend to perform better in a weight training session after consuming a pre-workout supplement. The scientist proposes that the caffeine in the supplement is increasing arousal, leading to increased performance. Which term best describes this scientist's proposal?

Answer 48

Hypothesis

Question 49

Which observational study design allows scientists to hypothesize a potential causal association?

Answer 49

Cohort study