Abstract
Background: Given the high prevalence of obesity and the poor long- term success of traditional weight loss treatments, non-dieting approaches are attracting increasing attention. Recent studies have shown that a number of psychological and behavioural characteristics such as intuitive eating, mindfulness and psychological flexibility may be important in influencing weight gain and degree of obesity in adult women. Non-dieting intervention studies suggest that training in these characteristics may have beneficial effects for preventing weight gain or promoting weight loss. However, intuitive eating, mindfulness and psychological flexibility, and their associations with obesity, have rarely been examined in representative samples of adult women.
Objectives:
1. To examine the association between levels of intuitive eating and BMI, with food patterns as hypothesized mediators.
2. To examine the associations between the three subscales of the Intuitive Eating Scale and BMI.
3. To examine the association between levels of mindfulness and BM I.
4. To investigate if there is a correlation between intuitive eating and mindfulness.
5. To examine the association between levels of psychological flexibility and BMI, with food patterns as hypothesized mediators.
Design: A nationwide study of 2500 New Zealand women aged 40-50 years, randomly selected from the electoral rolls, including Maori rolls. The study involved three phases. In the first phase, the questionnaire was developed and carefully pre-tested with 36 local middle- aged Dunedin women. In order to refine the mail survey design, a pilot study of 100 women who were randomly selected from the electoral rolls was conducted in phase two. The third phase of the study was the main survey of2500 women (66% response rate; n=1601). Subsequent to and separate from this Masters research, a two-year follow-up study will be carried out.
Outcomes:
1. Total intuitive eating scores and all three of the intuitive eating subscale scores were statistically significantly inversely associated with BMI, after adjusting for demographic, health and behavioural variables (age, smoking status, menopause status, thyroid condition, ethnicity, physical activity and socio-economic status) (p<0.001). The relationship between intuitive eating and BMI was partially mediated by frequency of binge eating. When controlling for all demographic, health and behavioural variables, as well as food patterns which were hypothesised as mediators, there was a statistically significant inverse association between total intuitive eating scores and BMI (-5.1% for every 10-unit increase in intuitive eating; 95% Cl: -6.1 %, -4.2%). After controlling for demographic, health and behavioural variables, a one-unit increase in the Unconditional Permission to Eat subscale, the Eating for Physical Reasons subscale, and the Reliance on Hunger and Satiety Cues subscale of the Intuitive Eating Scale, corresponded to a decrease in BMI of 0.66% (95% Cl: -0.84%,
-0.48%; p<0.001), 1.36% (95% Cl: -1.54%, -1.17; p<0.001) and 1.71% (95% Cl: -1.98%, -1.44%; p<0.001), respectively.
2. Higher mindfulness scores were statistically significantly associated with lower BMI after controlling for demographic, health and behavioural variables ( -1.0% for every 10-unit increase in mindfulness; 95% Cl: -1.9%, -0.10%; p=0.022). There were moderate statistically significant associations between mindfulness scores and the total intuitive eating scores (0.34) and the Eating for Physical Reasons subscale of the Intuitive eating scale (0.36).
3. Higher levels of psychological flexibility (and lower levels of experiential avoidance) were statistically significantly inversely associated with BMI while controlling for demographic, health and behavioural variables (-1.7% for every 10-unit increase in psychological flexibility; 95% Cl: -0.27%, -0.07%; p=0.001). The relationship between psychological flexibility and BMI was partially mediated by each of the individual food patterns: binge eating, intake of cakes, scones, muffins and sweet buns and intake of burgers. However, the relationship between psychological flexibility and BMI was statistically fully mediated by the combination of all three of the food patterns.
Conclusions: The study findings suggest that higher levels of intuitive eating, mindfulness and psychological flexibility are each positively associated with healthy food patterns and inversely associated with BMI in mid-age women. The direction of causality of these associations remains to be examined in the 2-year longitudinal study.