The Relationship Between Weight Loss and Time and Risk Preference Parameters: A Randomized Controlled Trial

Abstract

This study aimed to assess the effectiveness of intervention (specifically, intervention by telephone and mails, known as 'tele-care') relative to self-help as a weight-loss method. The question of whether there is a correlation between changes in two preference parameters--time discounting (i.e. impatience) and risk aversion--and the level of commitment was examined. The study, spanning a period of 24 weeks in 2006-2007, comprised 118 participants, each of whom was randomly assigned to either the tele-care or the self-help group. A public-health nurse provided support through telephone and mail communications to the tele-care group, aiming to reduce their calorie intake and increase exercise via this intervention. There was a significant decrease in the body weight of the participants of the tele-care group from the baseline; however, there were no significant differences in the weight loss, median time discounting or risk aversion between the two groups. The subsequent analysis for weight loss with changes in time and risk parameters revealed a significant difference in the weight loss in the time-discounting-loss and risk-aversion-gain groups. From the results of the multiple regression analysis, the time discounting was noted to be associated with age, initial BMI and marital status among men, and risk aversion was associated with age and job status among women. There is a possibility that a decrease in time discounting and increase in risk aversion might correlate with the weight loss or effectiveness of commitment in this trial. This study suggests that time discounting and risk aversion may be useful in anti-obesity efforts, since they are accurate criteria of behavioural patterns associated with weight problems.

Development and Validation of a Short Scale to Measure How Social Relationships Support the Continuous and Conscious Endeavour to Lose Weight

“…The participants were registered members of a community health club in Kyoto, Japan, recruited through a public advertisement. They were all obese but otherwise healthy men and women between 20 and 70 years old who met the study's strict eligibility requirements (for more details, see Takada et al, 2011). There were 118 participants at baseline, and 21 dropped out before the intervention started.…”

“…However, the literature shows that these two factors play an important role in preventing obesity (Sallis et al, 1992). Second, the participants in the Takada et al (2011) study were recruited through a public advertisement, so there may have been a self-selection bias, although participants were subsequently randomized into the tele-care and selfhelp groups. If the SRPO is to be employed in a particular population, demographic characteristics, in particular, potential confounding factors such as age and job status should be taken into consideration.…”

“…The objective of the present study was to develop and evaluate the validity and reliability of the SRPO. For this purpose, it uses secondary data from Takada et al (2011). The SRPO is a refined and extended version of a previous scale titled 'Social Support to Counter Obesity' (SSCO; Takada et al, 2010); the SRPO differs from the SSCO in that the latter does not explicitly measure social support that promotes self-control.…”

Current review of intervention studies on obesity and the role of physical activity in weight control

“…In addition, study protocols without results that were identified were excluded. Eighteen articles were excluded, and the remaining 10 articles [34][35][36][37][38][39][40][41][42][43] are summarized in Table 1.…”

“…The other studies found in our literature review focused on computer tailored advice 34,36) , telephone and mail support 37) , tailor-made lifestyle modification 40) , hot bathing 41) and dairy delivery 43) . Although all RCTs provided valuable findings, RCTs in this specific field in Japan were quite limited.…”