Self-Control in Intertemporal Choice and Mediterranean Dietary Pattern

Abstract

Background: The Mediterranean Diet (hereinafter MD) is considered a healthy dietary pattern. Adherence to this pattern can be assessed by means of the KIDMED test by which individuals are assigned an index and classified into three groups of adherence to MD: high, medium, and low. In addition, impulsivity or impatience in intertemporal choice has been defined as a strong preference for small immediate rewards over large delayed ones.Objective: This study examines the relationship between dietary habits, specifically Mediterranean dietary pattern, measured by the KIDMED index, and the exhibited impatience in intertemporal choices, by means of the parameter k (discount rate of the hyperbolic discount function).Methods: A sample of 207 university students answered a questionnaire based on two tests: the KIDMED test, to assess the degree of adherence to MD, and an intertemporal choice questionnaire, to assess impatience or impulsivity. Individuals were grouped depending on their KIDMED score and then the discount rate or impulsivity parameter was calculated for each group.Results: Discount rates were inversely related to the degree of adherence to MD. The values of overall k were 1.53, 1.91, and 3.71% for the groups exhibiting high, medium and low adherence to MD, respectively. We also found higher k-values for larger rewards (magnitude effect) in the three groups.Conclusion: High adherence to MD is related to less steep time discounting, which implies less impulsivity (more self-control) or lower discount rates. Conversely, low adherence to MD is related to steeper time discounting, which implies impulsivity or higher discount rates. These findings could be used to identify the target population where policy interventions are needed in order to promote healthier diet habits.

A New Analysis on Self-Control in Intertemporal Choice and Mediterranean Dietary Pattern

“…This paper completes Muñoz Torrecillas et al (1) results and conclusions investigating the relationship between adherence to healthy dietary habits, specifically the Mediterranean Diet (hereinafter, MD), and impulsivity in intertemporal choices. Impulsivity can be defined as the strong preference for small immediate payoffs over larger delayed payoffs, and in the original study this behavior was captured by the parameter k (discount rate of the hyperbolic discount function), calculated using an automated scoring mechanism.…”

“…Muñoz Torrecillas et al (1) observed that participants in the highest diet adherence group exhibited the lowest impulsivity, and participants in the lowest diet adherence group displayed the greatest impulsivity (see Figure 1; larger k -values represent greater impulsivity), but these differences were not statistically analyzed. Therefore, the purpose of the present paper is to quantitatively model the relationship between dietary adherence and impulsivity, and put forth preliminary evidence regarding its nature.…”

“…Therefore, a closer investigation into how an individual's dietary intake and economic decision-making influence each other is crucial to accomplishing the goals of public health policies. Muñoz Torrecillas et al (1) set out to explore this relationship in people by testing whether greater adherence to MD was associated with lower impulsivity. And if such a meaningful connection was found, then subsequent research could examine this association within a causal scope, possibly leading to the development of interventions prescribed to promote improvements in one's diet and self-control.…”

“…Raw k -values for small, medium, and large delayed rewards, by the three diet adherence groups. Original graph from Muñoz Torrecillas et al (1). …”

A systematic investigation into the reliability of inter-temporal choice model parameters

“…Increasingly, these models have been used as measurement tools, whereby parameter estimates are interpreted as indices of latent components of the choice process. For example, estimates of the discount rate parameter of the hyperbolic and exponential models, which reflects the rate at which future outcomes are discounted, is often used as a measure of impulsiveness (e.g., Kirby, Petry, & Bickel, 1999;Muñoz Torrecillas et al, 2018). Differences in discount rate parameter estimates have been explored between people of different age groups (Samanez-Larkin et al, 2011), clinical populations (Cheng & González-Vallejo, 2014), and across a variety of experimental manipulations (Haushofer et al, 2013;Li et al, 2018;S.…”