Presenter:

Andrew W. Brown, PhDNutrition & Obesity Research Center - Office of

EnergeticsUniversity of Alabama at Birmingham

awbrown@uab.edu Moderator:

James M. Rippe, MD – Leading cardiologist, Founder and Director, Rippe Lifestyle Institute

Approved for 1 CPE (Level 2) by the Commission on Dietetic Registration, credentialing agency for the Academy of Nutrition and Dietetics.

NUTRI-BITES®

Webinar Series

In the Eye of the Beholder:Critical Evaluation of Nutrition

Research

Original recording of the March 12, 2015 webinar and PDF download of presentation available at:www.ConAgraFoodsScienceInstitute.com

March 12, 2015

Based on this webinar the participant should be able to:  State potential influences of biases in nutrition

research Discuss the importance of critically evaluating

new research (i.e. whether it confirms or refutes standard clinical practice or commonly held beliefs)

Describe steps to minimize misinterpretation of research

Identify strategies health professionals can use to objectively translate scientific knowledge to clinical practice

 

NUTRI-BITES®

Webinar Series

Critical Evaluation of Nutrition Research

• How do we know about nutrition?• Critically evaluating research to minimize

misinterpretation• What exactly was studied?• How exactly was it studied?• How does that compare to how it was communicated?

• Translating science to clinic or policy

Outline

Nutrition Quadrilateral

Research

How do we ‘know’ things in Nutrition Science?

Reason

Tradition ExperienceThe quadrilateral requires of a [nutrition scientist] no more than what he or she might reasonably be held accountable for: which is to say, a familiarity with [scientific literature] that is both critical and faithful; plus, an acquaintance with the wisdom of [nutrition science history]; plus, a taste for logical analysis as something more than a debater’s weapon…

adapted from Outler. Wesleyan Theological Journal. 1985;20:1,p17

How Researchers Define Snacks and Meals• By time: 8-10AM, 12-2PM, and 6- 8PM = meals; Other times = snacks

• By food composition/type: Based on ‘taxonomy’ of food, or calories in eating occasion

(Gregori et al, 2011; Gregori, & Maffeis, 2007)

How Individuals Define Snacks and MealsMeal Related-Perceptions Snack Related-Perceptions

Eating with family vs. Eating alone

Cloth napkin vs. Paper napkin

Sitting while eating vs. Standing while eating

Expensive vs. Inexpensive

Prepared food vs. Packaged food

‘Healthy’ food vs. ‘Unhealthy’ food(Adapted from Wansink et al, 2010. Appetite. 54(1), 214-16)

Abstract concepts

orThe Tale of Two Cheese Sandwiches

What exactly are we comparing?

“Whole” Food Processed Food

Bread Multi-grain bread with whole sunflower seeds and whole-

grain kernelsWhite bread

Cheese Cheddar cheese Processed cheese product

Fat 17.5 g 14.5 g

Protein 20 g 15 g

Carbohydrates 40 g 49.5 g

Sandwich 2 slices of bread2 slices of cheese

3 slices of bread2.28 slices of cheese

“We … offer the contrary view that [self-report measures of EI] are so poor as measures of actual EI … that they no longer have a justifiable place in scientific research aimed at understanding actual EI...” – N.V. Dhurandhar et al., Int J Obes (Lond). 2014 Nov 13

Normalweight Overweight0

1000

2000

3000

4000

Self-reported and Observer-es-timated Energy Intake

1 day food record Research dietary history

kcal

/d

“It appears, therefore, that, unless special precautions are applied to the study of the fourth of the adult population which is overweight, any data collected on the caloric intake of populations by the record method is likely to be an underestimate.”

Are the methods good enough?

JADA, January 1953

Spin perpetuates throughout the reporting

Spin: specific reporting strategies, intentional or unintentional, emphasizing the beneficial effect of the experimental treatment

Bias Presented to the Public

Abstracts were categorized based on results and conclusions about breakfast and obesity

Breakfast was more likely to be mentioned in conclusions if results were pro-breakfast (p=0.0492)

Biasing Interpretations of Own Results

Brown A W et al. Am J Clin Nutr 2013;98:1298-1308

Selective Reporting

22%

78%

Not Pro-Breakfast Results

65%35%

Pro-Breakfast Results

Mentioned in Conclusions

Not mentioned in conclusions

CONCLUSIONS: “These schoolchildren are exposed to an obesogenic environment, and it is not surprising that in this situation, many of these children are already overweight and will likely become obese as adults.”

RESULTS: “Based on our observations, it appears that those who have higher BMIs are less likely to consume fast food as often.”

Conclusions not matching results

PMID:22721691

Adapted from: Brown A W et al. Am J Clin Nutr 2013;98:1298-1308

Being cognizant of our own humanity

Food X is Bad!

Mere Exposure Effect

Food X is Bad!

Food Xis

BAD!

Food X is OKAY

Cognitive Dissonance

Confirmation Bias

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

Strength of BeliefStrength of Evidence

Studies

Cert

aint

y (%

)

Discarded information

Often impossible to tell if something ‘worked’ for an individual (e.g., responders vs non-responders)• Improvements could have been spontaneous• Improvements may have been better with another

option• Impairments may have been mitigated

Scientific investigation tells us whether, on average, a group does better under one condition than another• RCTs in particular tell us whether a change in

exposure causes a change in outcome

The plural of anecdote is not ‘data’

Anecdote vs Data