Both psychological and physiological processes contribute to health and wellbeing. Chronic stress, meaning insufficient recovery, can lead to ill health via psychological, physiological, and behavioral processes. Chronic stress, as also dietary factors, are closely related to obesity and low-grade inflammation; these are underlying factors in several common diseases, e.g. type 2 diabetes and cardiovascular diseases. An individual’s risk for these diseases could be reduced if he/she made lifestyle changes, but making long-term behavioral changes is challenging, partly because of psychological inflexibility. Thus, psychological interventions are needed.
In her doctoral thesis, ELina Reijola-Järvinen, MHSc, aimed to investigate how stress and recovery are associated with eating behavior and diet by adopting a cross-sectional approach and whether an intervention based on psychological acceptance and commitment therapy (ACT) could change eating behavior, diet, and circulating biomarkers of stress and low-grade inflammation among working-age adults with psychological distress and overweight/obesity.
A total of 339 volunteers were randomized to the Elixir multicenter randomized controlled trial. In the baseline cross-sectional analyses, 297 participants (84% females, aged 27 – 61 years) provided the data. The post-intervention measurements were conducted after the 8-week intervention at study week 10 with follow-up measurements made on study week 36. With respect to the intervention effects, the analysis focused on the two ACT-based intervention groups (Face-to-face, n=70; six group sessions, and Mobile, n=78; one group session and mobile app) compared to the Control group (n=71; only the measurements). Perceived stress was measured with a questionnaire (PSS-14). Physiological recovery was based on heart rate variability (HRV) recording on three consecutive nights. Eating behavior was assessed with several questionnaires (TFEQ-R18, HTAS, IES-1, ecSI 2.0TM, REBS). Diet was assessed with questionnaires (IDQ, AUDIT-C) and 48-h dietary recall. The biomarkers of stress and low-grade inflammation (hsCRP, IL-1Ra, HMW-adiponectin, cortisol, DHEAS) were analyzed from morning fasting blood samples.
Perceived stress was associated with lower levels of intuitive eating, eating competence, and cognitive restraint as well as with higher levels of uncontrolled eating, emotional eating, and using food as a reward. No associations were found between perceived stress and diet. Sleep-time recovery was associated with lower intuitive eating, lower alcohol consumption, and higher diet quality (IDQ score) and fiber intake. A subcomponent of intuitive eating (i.e., eating for physical rather than emotional reasons) increased in both ACT groups and uncontrolled eating decreased in the Face-to-face group as compared to Control. Using food as a reward decreased in the Mobile group as compared to the Face-to-face group. Food acceptance and internal motivation for regulation of eating increased in the Face-to-face group as compared to both Control and Mobile groups. ACT did not seem to have any effect on diet. The hsCRP decreased in the Face-to-face group as compared to the Mobile group but no other effects on stress and inflammation biomarkers were observed. In additional exploratory principal component analyses of psychological, physiological, anthropometric, and lifestyle measures, it was found that weight-related psychological flexibility was the only psychological variable which was linked with stress and inflammation biomarkers in the same principal component.
In conclusion, perceived stress associates with unfavorable eating behavior. Better sleep-time recovery is linked with better diet quality. Thus, perceived stress and physiological recovery are relevant factors in nutrition science and clinical practice. More research and methodological development are needed to clarify the interactions between stress, recovery, eating behavior and dietary intake. ACT improves eating behavior and is thus a promising method for health-promotion and chronic disease prevention in people with psychological distress and overweight/obesity. If improvements in diet quality or physiological biomarkers are expected, it is proposed to focus the ACT intervention content to target that goal.
The doctoral dissertation of Elina Järvelä-Reijonen, Master of Health Sciences, entitled Stress, eating behavior, diet, and the effects of acceptance and commitment therapy among adults with psychological distress and overweight, will be examined at the Faculty of Health Sciences on 17 January 2020. The Opponent in the public examination will be Docent Hanna Konttinen of the University of Helsinki, and the Custos will be Professor Marjukka Kolehmainen of the University of Eastern Finland.
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