Wednesday, June 29, 2016

Moderation is Subjective and Susceptible to Bias

I discussed the concept of moderation in an earlier post.  My problems with moderation as dietary advice include: that moderation is poorly defined and very subjective; it can be used by the food industry to legitimise their unhealthy products; and some people do better with abstinence than with moderation

The problems with the first point – the subjectiveness of moderation – was well illustrated in a recent paper [1].  In the introduction, this paper cites earlier research that found: (1) people are poor judges of food intake; (2) people look to their peers and themselves to determine what ‘moderate’ consumption should be; (3) people’s beliefs are biased to favour themselves

Study 1

The first study involved asking female students about how many cookies: (1) one should eat; (2) would be moderate consumption; and (3) would be considered indulgent

On average, the participants reported that they should eat 2.25 cookies and that a ‘moderate consumption’ was 3.17 cookies

Study 2

The second study involved asking people taking a survey how many candies would be: (1) a reasonable amount to eat in one sitting; (2) eating in moderation in one sitting; or (3) what they should eat in one sitting.  Then they reported how much they like the candies

On average, the participants reported they should eat 8.87 candies, moderation consumption was 10.93 candies, and a reasonable amount was 14.17 candies.  There was also a correlation between the number of candies reported as moderate consumption with the liking of the candies (r = 0.38, p < 0.0001) and the reported consumption of those candies (r = 0.27, p = 0.007), whereas correlations were weaker or not significant for ‘should eat’ and ‘reasonable amount’

Study 3

The third study involved asking people taking a survey to report their average consumption of various foods and how moderate they thought their consumption of those foods

On average, the participants rated their consumption as moderate (4.50 and 4.47 on a 1-7 point scale, where 1 = ‘not at all’, and 7 = ‘very much’).  Across the 12 food and beverage categories, participants on average defined moderate consumption as greater than their personal consumption

There was also a correlation between reported personal consumption and what was reported as ‘moderate consumption’ (r = 0.52, p < 0.001 and r = 0.50, p < 0.001).  This correlation wasn’t disproportionate seen in people who were overweight.  However, there was no correlation between (1) the participants’ personal consumption with the participants’ rating of their consumption as moderate; and (2) the participants’ rating of their consumption as moderate with how much they believed was moderate consumption


Moderation could work as a concept, but not in situations where people’s reference point is one where they should be eating unhealthy food and that moderation involves eating a greater consumption of unhealthy food; or where most people believe they are already doing so well (when most people clearly aren’t) that moderation would once again involve a greater consumption of unhealthy food

For moderation to work, I think you would need to define ‘should’ as 0 and moderation as only slightly above 0, and for most people for moderation to mean something closer to self-discipline than a self-rationalised or socially acceptable indulgence 

If you want to adopt the recommendation of moderation, then I suggest you acknowledge then try to account for your biases and operationalise what moderation means.  Then most importantly, make adjustments based on the feedback your body is giving you

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