The term ‘intuitive eating’ was coined by research dietitians Evelyn Tribole and Elyse Resch in 1995, and, as highlighted in ongoing intuitive eating research, is characterised by eating according to internal hunger and satiety cues, rather than external stimuli or situational and emotional cues.
Tracy Tylka’s research group clustered the principles of intuitive eating into four overall domains to measure intuitive eating using the validated Intuitive Eating Scale-2 [IES-2]:
- Unconditional permission to eat;
- Eating for physical rather than emotional cues;
- Reliance on hunger and satiety cues, and;
- Body-food choice congruence.
Intuitive eating may be considered an “adaptive eating style”, a term which broadly encompasses ways of eating that promote a positive relationship with both food and the body, guided by internal physiological cues.
The Acceptance Model of Intuitive Eating
It is easy to think of intuitive eating as a construct purely related to diet, and also to see it as an outcome, i.e., something to develop by reference to dietary behaviours.
However, as can be gleaned from certain of the principles of intuitive eating, the body is a crucial aspect of the overall construct.
IE promotes respect for the body, a focus on the body’s function [i.e., exercising for enjoyment], and food choices based on congruence with the body.
Drawing on research from different psychological theories and eating disorders research, Tracy Tylka’s research group developed the ‘Acceptance Model of Intuitive Eating’ [AMIE], a pivotal framework in intuitive eating research.
This model drew on humanistic theory, that individuals who receive unconditional acceptance from others are more likely to accept their own self as they are.
It also drew on objectification theory, commonly applied in eating disorders research, where the experience of being objectified leads to self-objectification, and ultimately body shame, which manifests as disordered eating/eating disorder.
AMIE posits that the experience of body acceptance and/or unconditional acceptance from others reduces one’s self-focus on the body’s appearance, in turn leading to an increased orientation towards body function, i.e., what the body can do.
This focus on what the body can do leads to an appreciation for one’s body.
Both a greater focus on the body’s function and increased appreciation for the body contribute to more intuitive eating because the individual is eating for physical rather than emotional reasons and because they are eating by their body’s physiological needs [i.e., for exercise].
The research to date, albeit limited, has been suggestive of this direction of effect; that body acceptance by others predicts body function appreciation and bodily self-acceptance, which in turn predicts intuitive eating.
However, the research does suggest potential differences according to age [i.e., stronger in early middle-aged women vs. younger adult women], and sex [stronger in women vs. men].
Before the publication of a 2021 study, there had been no research quantitatively synthesising the available research on the AMIE within the field of intuitive eating research.
Quantifying Intuitive Eating
In 2021, Jake Linardon et al. conducted the first meta-analysis of IE and psychological outcomes.
The study investigated the overall strength and direction of effect of IE on psychological health outcomes, and whether gender differences and factors such as age and BMI moderated the associations.
The analysis also investigated whether the effects of IE differed between individuals with or without an eating disorder.
The final aim of the study was to determine the strength of evidence for the AMIE.
What about the results?
Higher IE scores were associated with lower levels of binge-purge symptoms, restrained eating, internalised appearance ideals, and body shape/weight concerns.
Higher IE scores also correlated with higher levels of body acceptance by others, body appreciation, and self-compassion.
Comparing healthy participants to those with clinical eating disorders on IE scores showed a very large effect size that indicated individuals without clinical eating disorders have substantially higher levels of IE compared to those with a clinical eating disorder.
Finally, overall, men reported higher levels of IE compared to women.
The latter finding is not that surprising given the dysregulation of eating according to internal cues that accompanies eating disorders.
What About the Acceptance Model of Intuitive Eating?
Arguably the most interesting aspect of the present study’s analysis, and a significant contribution to intuitive eating research, is the AMIE.
Each step in the pathway was significantly associated with its subsequent step [e.g., body function to body appreciation; body appreciation to intuitive eating], except for the pathway beginning with unconditional acceptance by others.
Unconditional acceptance from others was not significantly correlated with body function.
However, body acceptance by others was significantly correlated with body function, body appreciation, and directly to IE.
The analysis indicated a clear direction of effect, e.g., body acceptance by others positively influences body function, body appreciation, and IE.
It also showed that an emphasis on body function and body appreciation, respectively, predicted IE.
The lack of effect of unconditional acceptance from others is consistent with previous research on the AMIE found in broader intuitive eating research.
The strong predictive effect of body acceptance by others is also consistent.
For example, a 2015 study in adolescent girls found that body acceptance by others influenced both body appreciation and IE through social appearance comparison and self-objectification.
In simple terms, being accepted for their body lowered levels of self-objectification and comparing oneself to the appearance of others, which in turn influenced IE.
Fascinatingly, the available research suggests that general social acceptance may not be sufficient and that it is acceptance specifically related to the body that predicts improved body image and appreciation, and consequently, IE.
This has relevance for the findings of this meta-analysis. Recall that men exhibited higher IE scores compared to women.
If we take the pathway analysis on the AMIE together with previous research, this may be because women face greater bodily objectification and pressure to conform to beauty ideals.
Where Does the Strength of Evidence Stand?
The research on intuitive eating [IE] continues to expand across the landscape of intuitive eating research, but the main limitation to the overall body of evidence is the lack of prospective data.
The Lindardon et al. meta-analysis was based on cross-sectional data only, and there remains a real lack of prospective longitudinal studies examining IE and changes in relevant outcomes over time.
One important potential limitation of this research, which the authors highlight to their credit, is that in a cross-sectional design participants may answer IE assessment questions as a reflection of how they would like to eat, rather than how they do in fact eat.
This is another reason why more prospective research is warranted in this area.
However, the limited prospective data that has examined associations between IE and eating behaviour outcomes over time is consistent with what may be expected from the more voluminous cross-sectional data.
For example, the U.S.-based Project EAT showed that participants who were classified as ‘intuitive eaters’ as young adults exhibited lower BMI, less dieting, less unhealthy weight control behaviours, and less binge eating, compared to ‘non-intuitive eaters’.
The first narrative review of IE by Van Dyke and Drinkwater in 2014 was not a systematic review and included studies on other adaptive eating styles such as HAES and mindful eating.
A second review conducted by Bruce and Ricciardelli in 2016 was a systematic review of 24 cross-sectional studies and included only studies that assessed IE specifically using validated IE scales.
Bruce and Ricciardelli’s systematic review found that higher IE scores were associated with positive body image and appreciation, lower levels of body dissatisfaction, and lower levels of unhealthy weight control behaviours.
The Linardon et al. study, as the first quantitative synthesis, indicates that higher IE scores correlate with overall positive psychological wellbeing, including body image-related and dietary-related outcomes.
It remains for more prospective studies, and intervention trials in particular, to improve the robustness of this evidence-base.
However, perhaps the most important takeaway from the Linardon et al. analysis relates to the direction of effect of factors predicting IE as elucidated in the AMIE analysis.
Self-objectification, bodily surveillance and body dissatisfaction, and lack of perceived bodily acceptance, would all converge to act as barriers to IE.
Thus, as an adaptive eating style, IE may not be independent of social and environmental factors.
This is something that should be considered both in the research on IE and its application in real-world contexts, ultimately guiding the next wave of intuitive eating research.
Yours in Science,
Alan
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