People who have participated in intermittent fasting in the past might be at heightened risk of binge eating, according to new research published in the journal Appetite.
Binge eating disorder is a serious condition that can lead to obesity, diabetes, and other health problems. Intermittent fasting, on the other hand, is a popular diet trend that may offer health benefits such as weight loss and improved blood sugar control. However, research has yet to fully understand how these two behaviors interact and how different types of intermittent fasting may affect the risk of binge eating and other detrimental behaviors.
“I am currently working on my PhD in Clinical Psychology, and I have always been interested in learning more about the relationship between disordered eating and risk factors, such as a history of dieting or trying to restrict one’s food intake,” explained study author Jordan Schueler, a graduate student at Texas A&M University.
“At the time that I came up with the idea for this study, which was back in 2019, I had only heard of ‘intermittent fasting’ but did not know much about it. Still, my mind immediately went to what I knew from the research: restrictive eating or excessive dieting can lead to the development of eating disorders.”
“I endeavored to learn more about the subject and see what research had been conducted already,” Schueler said. “I was incredibly surprised to find that there really was not much out there about the psychological effects of intermittent fasting — only how it affected medical outcomes such as weight, cholesterol, etc.”
For their study, Schueler and her colleagues recruited a sample of 70 individuals who were currently engaged in intermittent fasting, 48 individuals who had previously engaged in intermittent fasting, and 182 individuals who had never engaged in intermittent fasting. The participants were recruited through a psychology department subject pool.
The researchers asked participants some basic questions about their dietary habits. Those who were currently engaged in intermittent fasting were asked further questions about their experience with different types of intermittent fasting (time-restricted fasting and alternate-day fasting) and their reasons for doing so. They were also asked how long they had been fasting.
The participants also completed the Short UPPS-P Impulsive Behavior Scale (which assesses five facets of impulsivity), the Intuitive Eating Scale 2 (which assesses the extent to which individuals rely on hunger or emotional cues to determine when to stop or start eating), the Eating Disorder Diagnostic Scale for DSM-5 (a diagnostic assessment of binge eating, anorexia, and purging behaviors), and the Mindful Eating Behaviour Scale (which assesses the degree to which individuals eat with attention to their present thoughts and sensations).
Of participants who were currently engaged in intermittent fasting, only 57.1% viewed themselves as currently dieting and 87.1% were following no specific dietary restrictions. Most (58.7%) reported that they had started intermittent fasting in an effort to lose weight or alter their body composition. A large majority (90%) indicated they were following a time-restricted fasting regimen.
Concerningly, compared to those who had never engaged in intermittent fasting, individuals with a past history of intermittent fasting tended to report greater engagement in binge eating.
“Our study results demonstrated that past engagement in intermittent fasting was associated with greater binge eating,” Schueler told PsyPost. “While binge eating by itself can make someone feel physically and emotionally uncomfortable, it is also linked to several medical and psychological concerns, including type 2 diabetes, hypertension, substance abuse, or mood or anxiety disorders (Hudson et al., 2010; Kornstein et al., 2016).”
“Additionally, intermittent fasting was negatively related to intuitive eating, or eating according to your internal hunger or fullness cues, meaning that people who were engaging (or had done so in the past) in intermittent fasting were less likely to eat according to their internal hunger cues or their physiological needs (e.g., stamina, energy). As you might guess, eating not when you’re hungry, but on a schedule, can cause some problems with your appetite or lead to some functional issues.”
“However, more research needs to be done to fully understand how intermittent fasting is associated with harmful psychological effects, such as disordered eating, preoccupation with food, body image concerns, depression, or anxiety,” Schueler said.
Interestingly, there was no statistically significant difference in binge eating episodes between those currently fasting and those who had never fasted.
“While I was not surprised that past intermittent fasting could lead to increased binge eating, I was surprised that episodes of binge eating were highest in this group compared to those who were currently fasting,” Schueler explained. “However, after reflecting it on some more, I think it makes sense. Long-term dieting or a history of dieting can often lead to overeating due to the pervasiveness of one’s continued thoughts and preoccupation with food or their weight.”
“And what happens when we consistently diet or limit our food intake? We get hungry! But instead of getting a little hungry, which most of us do on a regular basis, we get really hungry and may eat rapidly, almost as if we’re not able to control how much we’re eating, and end up eating more than we planned (e.g., binge eating). Of course, we had a smaller sample size for the group that had participated in intermittent fasting in the past (n = 48), so more research is needed to confirm this finding.”
Participants who were currently engaged in intermittent fasting scored higher on a measure of perseverance compared to those who had fasted in the past or who had never fasted. In other words, they tended to agree with statements such as “I usually make up my mind through careful reasoning” and “I generally like to see things through to the end.” But no other significant differences in impulsivity emerged.
“Additionally, I was surprised that there was no association between intermittent fasting and impulsivity,” Schueler told PsyPost. “Typically, we’ve seen in the literature that people who engage in binge eating tend to also be more impulsive. This makes sense given that binge eating may be seen as an impulsive food-making decision.”
“In particular, research indicates that individuals who engage in binge eating or bulimic behaviors (e.g., binge eating, purging or vomiting, or compensating for binge eating via diuretic or laxative use, excessive exercise, food restriction, etc.) tend to do so impulsively as a reaction to distress (also termed “negative urgency” in the research realm).”
“Therefore, why didn’t we see this with our individuals who were intermittent fasting and binge eating?” Schueler continued. “Well, I don’t have much to offer at this point in time. I think we need to look more into this to determine the extent to which other factors (e.g., experiencing of “negative” emotions, such as sadness, anger, worry, etc.) may be contributing to this.”
The study, like all research, includes some caveats. For instance, the lack of racial/ethnic diversity and focus on undergraduate students may limit the generalizability of the findings.
“In general, we need to ask these questions among more diverse groups of people,” Schueler explained. “Our study was lacking in its racial/ethnic diversity, and only focused on undergraduate students, which means that the results of this research cannot necessarily be applied to people who have less than an undergraduate degree or some college experience.”
“Additionally, we did not look at other important psychological variables such as depression, anxiety, emotional lability (rapid and, often, extreme mood changes), suicidality, etc. That is definitely a limitation of our study and needs to be further investigated in future research.”
The study, “Group differences in binge eating, impulsivity, and intuitive and mindful eating among intermittent fasters and non-fasters“, was authored by Jordan Schueler, Samantha R. Philip, Darya Vitus, Solangia Engler, and Sherecce A. Fields