between large/high-impact nutrition risks
and small/low-impact nutrition risks.
Let’s take an example (with numbers
rounded and approximated slightly for ease
of discussion). A widely cited research find-
ing is that eating 50 g of processed meat
daily (eg, four slices of bacon) increases
the risk of developing colorectal cancer
by about 16%.^7 That’s the relative risk. The
absolute risk of colorectal cancer in the
United States is approximately 4%.^8 The
16% increase in relative risk increases
the absolute risk from 4% to about 4.6%.
So eating 50 g of processed meat daily
increases absolute risk by 0.6% (ie, 4.6%-
4% = 0.6%). In other words, if 1,000 people ate four slices of bacon
daily, 46 of them would develop colorectal cancer. If none ate four
slices of bacon daily and all other risk factors were equal, 40 of
them would develop colorectal cancer.
Some people will think the tradeoff of increased risk for bacon
consumption is worth making; some people won’t. But it’s diffi-
cult to begin to understand the tradeoff without understanding
the difference between relative and absolute risk. In addition,
the absolute risk reduction from most narrow dietary changes
offered by a popular book or oversensationalized headline will
be much smaller, and probably zero.
If dietitians worry that the absolute risk in the example above
will seem trivially small to their audiences, they can remind them
of a couple of things. First, small absolute risk changes do add
up, so overall impact of diet on disease risk is much larger than
0.6%. And second, even seatbelt use doesn’t reduce the absolute
risk of death by more than 1%,^9 yet 90% of Americans now wear
seatbelts.^10 And it’s a good thing, because the “small” reduction
in absolute risk translates into more than 10,000 lives saved in
the United States each year.^11 From a public health perspec-
tive, “small” absolute risk reductions can represent very large
public health wins.
Comparisons such as these may help people make decisions
when eating choices are addressed in messages that seem to rely
on exaggerated impressions of risk. For example, people may
become fearful that even very limited consumption of a food or
drink could doom them or their children to a major health prob-
lem. Confusion of hazard and risk complicates perceptions of risk,
too. Dietitians can remind patients that just because studies have
shown that exposure to very large doses of some chemicals cause
health problems in mice, it doesn’t mean that a dose 1/1000th that
size will cause any problems for patients and their families. A new
Twitter account, @justsaysinmice, offers a series of humorous and
informative tweets on this basic idea.
A detailed examination of risk communication is beyond the scope
of this article. For now, we’ll emphasize our general recommenda-
tion: Communicators should try to make it easier for people to con-
sider the magnitude of some risks vs others in their lives. Without
that absolute sense of risk magnitude, people will find it difficult to
understand the tradeoffs their choices entail.
Next Steps
Dietitians already are doing many things well to address critical
thinking failure. In Table 4, we examine the frequency of some of
these practices when speaking with patients or consumers who
have misperceptions about nutrition.
The answers are encouraging. And the concepts in this arti-
cle may offer additional details and perspectives that can help
guide dietitians in listening, connecting on shared values, and
building trust with clients and audiences. We also hope that the
topic of managing limitations in critical thinking will gain atten-
tion. Seventy-one percent of those surveyed said there weren’t
enough good resources to help dietitians prevent and correct
problems in critical thinking. Some are listed on our website
ThinkingandEating.com. More are needed. Human nature won’t
change, but culture and communication can.— Jason Riis, PhD, is president of the consulting
firm Behavioralize, and senior research fellow at the Behavior
Change for Good Initiative at the University of Pennsylvania.— Brandon R. McFadden, PhD, is an assistant professor
of applied economics and statistics and research
fellow at the Center for Experimental and Applied
Economics at the University of Delaware.— Karen Collins, MS, RDN, CDN, FAND, is a nutrition
consultant specializing in cancer prevention
and cardiometabolic health and nutrition
advisor to the American Institute for Cancer Research.Jason Riis, PhD, reports the following relevant disclosures: He serves as
consultant and spokesperson for Ajinomoto, Bayer Crop Science, Conagra
Brands, Produce for Better Health, Texas Beef Council,
and WW (Weight Watchers).
Brandon R. McFadden, PhD, reports the following relevant disclosures:
He serves as consultant and spokesperson for Bayer Crop Science,
Institute for Justice, and Texas Beef Council.TABLE 4
Percentage of Respondents Indicating They Do This “Most of the
Time” or “Always” When Speaking With Patients or Consumers
Who Have Misperceptions About Nutrition91% Actively build trust
90% Really listen to fully understand their perspective
82% Connect with them on shared values
For references, view this article on
our website at http://www.TodaysDietitian.com.40 today’s dietitian august 2019