Mothers’ DASH diet adherence and food purchases after week-long episodic future thinking intervention

Abstract

Prospection has helped participants forego the temptation to buy and eat higher calorie nutrient poor foods in favor of buying and eating fewer calories and healthier macronutrient profiles in laboratory tasks and brief field studies. This pilot study examines whether episodic future thinking (EFT) improves mothers’ dietary behavior and food purchasing over a longer 7-10-day period. The study utilized a 2 × 2 factorial design with mothers (N = 60) randomized to EFT or standardized episodic thinking (SET) crossed with dietary approaches to stop hypertension (DASH) diet education or a food safety education control. Participants listened to their cues (e.g., recordings of themselves imagining a future event or recalling a past episode) using a mobile ecological momentary intervention (EMI) tool and returned to complete a follow-up dietary recall and submit food receipts. Results showed diets of mothers in the EFT groups became more concordant with the DASH diet (η_p² = 0.08, p < .05) than mothers in the SET group. When considering food purchases for the family, there was an EFT effect on milligrams of sodium purchased (η_p² = 0.07, p < .05) and a trend towards a decrease in grams of fat purchased (η_p² = 0.06, p = .06), however, these findings were no longer significant after correcting for multiple comparisons. There were no DASH education effects and no DASH by EFT interactions observed. The dietary intake and food purchasing results should be replicated in larger more representative samples.

Introduction

Episodic future thinking (EFT) is a cognitive capability that enables one to mentally simulate a potential future (Atance, 2001). People vary in how frequently and vividly they imagine the future as well as how much weight they give to larger future rewards while making decisions. A focus on or preference for more immediate gratification over future benefit (e.g. delay discounting) has been associated with a number of maladaptive behaviors and poor health outcomes (Bickel, Jarmolowicz, Mueller, Koffarnus, & Gatchalian, 2012). It has been hypothesized that EFT may be an effective self-regulatory tool due to its demonstrated ability to 1) improve one's mood (e.g. reduce anxiety) while making a decision, 2) increase the valuation of larger-later rewards, 3) improve prospective memory, and 4) increase one's consideration of and planning for the future (Schacter, 2017). A burgeoning area of research instructs participants to simulate, write, or recall EFT narratives (i.e. cues) while completing DD tasks or engaging in health-related behaviors (e.g. smoking, eating, drinking). These EFT interventions have been associated with numerous beneficial outcomes, such as reduced delay discounting (DD) (Rung & Madden, 2018a), reduced snack food demand in a hypothetical purchasing task (Sze, Stein, Bickel, Paluch, & Epstein, 2017), reduced caloric intake in ad-libitum eating experiments in the laboratory (Daniel, Said, Stanton, & Epstein, 2015; Daniel, Stanton, & Epstein, 2013; Dassen, Jansen, Nederkoorn, & Houben, 2016) and reduced caloric intake in a food court (O'Neill, Daniel, & Epstein, 2016).

EFT has also helped parents with overweight and obesity lower BMI during a four-week family-based weight loss intervention (Sze, Daniel, Kilanowski, Collins, & Epstein, 2015). However, children in the EFT condition did not show differential changes in BMI in comparison to controls (Sze et al., 2015). These results suggest that training families in EFT will not automatically lead to an improvement in children's eating or activity behaviors. Thus, when working with families, it may be advantageous to go beyond traditional training in eating and exercise control to target parent's shopping behavior as a way to improve the shared home food environment (van Ansem, Schrijvers, Rodenburg, & van de Mheen, 2014).

Following the NIH Stage Model of Behavior Change (Onken, Carroll, Shoham, Cuthbert, & Riddle, 2014), we initiated a series of studies to test whether EFT could improve mother's household food purchases. In two earlier laboratory studies that used a simulated online shopping task, we found that EFT helped mothers with overweight and obesity to purchase groceries with fewer calories and healthier macronutrient profiles (Hollis-Hansen, Seidman, O'Donnell, & Epstein, 2019). These findings were then replicated in a three-day field study where mothers listened to their cues from their preferred device and shopped at their favored food retailers in the real world (Hollis-Hansen et al., 2020).

Extending upon the earlier work, one way to enhance the effectiveness and translation of EFT may be to combine it with dietary education that provides guidance on what to buy and eat, in addition to the self-regulatory assistance EFT may provide. The Dietary Approaches to Stop Hypertension (DASH) diet focuses dieters on eating vegetables, fruits, and whole grains, and limiting foods high in sodium, saturated fat, and sweets while not expressly restricting any specific macronutrients or food items. Dieters are instructed to consume 2000 calories per day and 1500–2300 mg of sodium (<1 teaspoon of salt) each day (Campbell, 2017). DASH is a relatively simple dietary approach to follow that has consistently proven effective at weight loss (Soltani, Shirani, Chitsazi, & Salehi-Abargouei, 2016), therefore it could help provide participant's a frame of reference for what to buy and eat during the intervention period.

This pilot study was designed to advance our knowledge of using EFT to improve dietary behavior and food purchasing. Female shoppers with children were randomized to one of four groups in a factorial design that studied EFT versus standardized episodic recent thinking (SET) crossed with DASH dietary advice versus food safety advice. In addition to studying female shopper's food purchases over a longer 7-10-day period, we also studied the women's dietary intake to assess if their dietary intake and food purchasing were influenced by EFT and/or DASH dietary education. We focused on mothers as they are the primary food shoppers and preparers for their family and a major influence on their children's eating behavior (Schaeffer, 2019).

We hypothesized that EFT participants would have better adherence to the DASH diet than the SET control group. We did not expect brief DASH diet education alone to influence dietary behavior, but we did hypothesize that there would be an EFT by DASH interaction, such that EFT would have a greater effect on DASH diet adherence in the EFT participants that received DASH education than either of the SET participants or the EFT participants that received food safety education. We also hypothesized that EFT groups would purchase fewer calories and healthier nutrient profiles than SET controls and that EFT would again interact with DASH education leading to the greatest improvement in foods purchased over the week-long intervention for those who received EFT accompanied by DASH diet education.

Most studies of EFT and DD instruct participants to read and recall their cues before or while making decisions during the DD task to modify temporal discounting. In recent work, researchers have not observed changes in discounting when cues are not presented during the DD tasks (Hollis-Hansen et al., 2019; Rung & Madden, 2019; Mellis et al., 2019). It is possible that more extensive experience with EFT may change temporal discounting even when no cues are presented. Rather than replicate the effects of EFT training on temporal discounting when EFT cues are presented, we tested whether one week of EFT cue recalls would change default thinking and improve DD without cues. Our exploratory hypothesis was that there would be an independent main effect of uncued EFT on change in DD from Time 1 to Time 2.