Episodic future thinking reduces delay discounting and energy intake in children

Highlights

• Episodic future thinking (EFT) improves delay of gratification in adults.

• EFT's effects on delay of gratification have not been examined in children.

• Our experiment examined EFT's effects in overweight/obese 9 to 14 year olds.

• Results that showed EFT led to less delay discounting and lowered energy intake.

• EFT reduced food intake the most when there was a higher desire to restrict intake.

Abstract

Discounting of larger future rewards in favor of smaller immediate rewards is known as delay discounting. High delay discounting or a bias towards immediate gratification impedes self-regulation and is associated with maladaptive eating behaviors. Children in general show greater delay discounting than adults. Obese children in particular, have greater difficulty delaying gratification for edible rewards. Episodic future thinking (EFT) which is mental self-projection to pre-experience future events reduces delay discounting and reduces energy intake in overweight/obese adults. However, these EFT effects have not been examined in children. We evaluated the effects of EFT versus control episodic recent thinking (ERT) on delay discounting and ad libitum energy intake while thinking about episodic cues in 42 overweight/obese 9 to 14 year olds. Results showed that EFT led to less delay discounting and lowered energy intake, and EFT had the greatest effect on reducing energy intake in children with a higher desire to restrict food intake. This suggests that EFT may be useful in pediatric obesity treatment programs to help children regulate energy intake.

Introduction

Obesity is caused by energy intake in excess of energy expenditure (Hill, Melanson, & Wyatt, 2000) and is associated with chronic conditions such as cardiovascular disease, stroke and type-2 diabetes (Björntorp, 1990, Larson et al., 2011). Despite the well-publicized adverse impact of obesity on health (Winter & Wuppermann, 2014), many individuals often over-indulge in unhealthy and high energy-dense foods. These individuals may prefer the immediate gratification of high energy-dense foods, instead of avoiding these foods for future health. This discounting of larger future rewards in favor of smaller immediate rewards is known as delay discounting and greater discounting occurs with increasing temporal distance between the immediate and delayed rewards (Bickel & Marsch, 2001). High delay discounting is cross-sectionally (Davis et al., 2010, Weller et al., 2008) and prospectively (Seeyave et al., 2009) related to obesity, and predicts greater consumption of high energy-dense ready-to-eat and away-from-home foods in obese women (Appelhans et al., 2012). Individuals with a high motivation to eat and high in delay discounting are more obese (Epstein et al., 2014) and have greater calorie consumption in ad libitum eating sessions (Appelhans et al., 2011, Rollins et al., 2010).

A bias towards immediate gratification may present an even greater barrier to healthy eating for children compared to adults. Children in general show greater delay discounting than adults (Green et al., 1994, Steinberg et al., 2009). Obese children in particular, have greater difficulty delaying gratification for edible rewards (Bonato & Boland, 1983), and they find food more reinforcing than their leaner peers (Temple, Legierski, Giacomelli, Salvy, & Epstein, 2008). Unfortunately, obese children that want to restrict calorie intake to reduce body weight have to delay gratification for food in order to lose weight. A bias towards immediate gratification can be an impediment to their ability to self-regulate food intake for future health and research shows that an immediate bias predicts diminished success with weight loss in obesity treatment (Best et al., 2012). Thus, techniques that reduce delay discounting or improve the ability to resist immediate gratification may reduce energy intake and improve weight loss.

One technique that reduces the bias towards immediate gratification is vividly imagining the future during decision-making using episodic future thinking (Daniel et al., 2013a, Peters and Büchel, 2010). Episodic future thinking (EFT) is a type of prospective thinking that involves mental self-projection to pre-experience future events (Atance & O'Neill, 2001). EFT emerges between the ages of 3 and 5 years (Atance, 2008). It engages the episodic memory network and uses autobiographical details to mentally simulate the future (Atance and O'Neill, 2001, Schacter et al., 2008). EFT is thought to increase the value of delayed outcomes during decision making (Benoit, Gilbert, & Burgess, 2011) and steer individuals towards choices with long term benefits (Boyer, 2008). Additionally, we have demonstrated that EFT reduces delay discounting and ad libitum energy intake during a tempting food situation in overweight/obese adults (Daniel et al., 2013b, Daniel et al., 2013a). While EFT ability emerges between 3 and 5 years of age (Atance & O'Neill, 2005), little is known about the effects of EFT in children.

The aim of this study was to investigate the impact of EFT compared to control episodic recent thinking (ERT) on delay discounting and energy intake in children aged 9 to 14 years old. Our goal was to obtain data which will help to address the research gaps on EFT's effect in children. We chose to study children aged 9 to 14 years because studies on developmental differences on delay discounting tasks typically examine children 9 years and above (Banich et al., 2013, Green et al., 1994, Steinberg et al., 2009). Similar to our previous study on EFT's effect on energy intake in adults, (Daniel et al., 2013b), we developed the ad libitum eating task in this study to maximize this as a tempting eating situation for an overweight/obese child.

We studied children who varied in their desire to restrict energy intake for weight loss (i.e. varied in dietary restraint) (Braet and Van Strien, 1997, Wardle et al., 2001) to test individual differences that influence responsiveness to EFT's effect on energy intake. We expect that children low in dietary restraint will be the least responsive to EFT's effect and those high in dietary restraint will be most responsive to EFT and consume less food. For an obese child who is not motivated to restrict calorie intake for health, resisting immediate gratification may be inconsequential and an ad libitum eating situation could be an opportunity to indulge.