A Qualitative Exploration of Facilitators and Barriers to Early Time-Restricted Eating: Insights From a Randomised Controlled Trial

Abstract

Background:

Adherence to time-restricted eating (TRE), a form of intermittent fasting, is typically high. However, the social, psychological, and environmental factors influencing adherence are unknown. Herein, we examined factors affecting participants’ adherence to early TRE (eTRE) relative to a control schedule and whether they intended to continue practicing TRE after the intervention.

Methods:

Ninety adults with obesity were enroled in a weight management programme and randomised to either an eTRE (8-h eating window from 07:00 to 15:00) or a control schedule (≥ 12-h eating window) for 14 weeks. Seventy-one participants (eTRE: n = 34, Control: n = 37) completed exit interviews exploring facilitators and barriers to adherence. Data were evaluated using thematic analysis.

Results:

Perceived health benefits, meal planning, reminders, and accountability promoted adherence to the prescribed meal timing interventions. Social relationships, break days, and unstructured or variable routines, particularly on weekends, served as facilitators or barriers, depending on the participant. Disruptions in family and social life were barriers. Most eTRE participants intended to continue practicing TRE after the study concluded, with modifications to better suit their individual circumstances.

Conclusions:

Planning meals in advance, setting reminders for when to eat, focusing on health benefits, and accountability help people adhere to eTRE. Strategies to promote adherence should be personalised and address irregular routines, as well as potential challenges to family and social life. Allowing some flexibility in meal timing schedules may also promote long-term sustainability.

1 |. Introduction

Time-restricted eating (TRE) is a form of intermittent fasting that involves eating within a consistent ≤ 10-h daily window and consuming nothing other than water and calorie-free beverages for the remaining ≥ 14 h of the day [1, 2]. TRE focuses on adjusting the timing of meals without requiring energy intake restrictions or changes in diet quality [3, 4]. Nonetheless, adults who practice TRE experience modest to moderate weight loss—a finding well supported by the literature [1, 5–14] [15–20]. TRE can also improve insulin sensitivity, blood pressure, cardiorespiratory fitness, fat oxidation, and oxidative stress even in weight-stable adults, particularly if the eating window ends by 6 PM [21–27].

One attractive feature of TRE is its apparent simplicity. TRE is perceived to be easy to follow as it does not require calorie restriction or changes to food choices [3]. Short-term adherence to TRE is reported to be usually high, with individuals typically adhering between 5.0 and 6.2 days/week (≈70%–90%) [8, 10, 14, 28–33] [13, 15, 34, 35]. [20, 36–38]. A systematic review of TRE trials reported a mean adherence of 80% [5], and a recent large randomised controlled trial found that adherence was high regardless of the time of day of the eating window. Moreover, these high levels of adherence may be sustainable. Two longer-term studies found that individuals were still practicing TRE about 6 days/week 1 year after the end of the study [33, 34]. Despite this encouraging data, our understanding of factors affecting adherence to TRE remains limited. Adherence data are typically reported as an average value, which fails to capture the distinct experiences of adherers and non-adherers. Quantitative approaches help identify relationships between individual-level factors, such as motivation [39] or conscientiousness [40] and adherence, they fall short in uncovering the “why” behind suboptimal adherence or identifying actionable strategies to overcome barriers. A more holistic understanding of facilitators and barriers could encourage long-term adherence to TRE, supporting its broader adoption.

Qualitative contextualisation using an idiographic approach can bridge this gap by offering rich insights and uncovering factors impacting adherence to TRE. To date, there have been only a handful of qualitative studies on TRE [41–47] which identified several important facilitators and barriers. However, these studies lacked a control group, had relatively small samples (typically n = 10–20), did not specify how adherence was evaluated, and/or were missing key protocol details, including the timing of the eating windows. Therefore, larger qualitative studies that rigorously compare TRE to a control eating schedule are needed.

We recently conducted a large-scale randomised controlled trial of TRE in adults with obesity and found that early TRE (eTRE) improved body weight, diastolic blood pressure, and mood [30, 48]. We prescribed an early eating window to optimally align meal times with circadian rhythms in metabolism—a strategy that may confer greater cardiometabolic benefits relative to a later eating window. As part of the trial, we tracked adherence using a daily survey and conducted a large number of semi-structured exit interviews (Supporting Information S1: Table S1)to explore participants’ experiences. Herein, we performed a qualitative thematic analysis to identify facilitators and barriers to TRE and assessed participants’ intentions to continue meal adjustment post-trial. This qualitative study is the largest of its kind and the first to include a control group, isolating factors unique to TRE.

2 |. Methods

2.1 |. Study Design and Population

The parent study was a 14-week, parallel-arm, randomised, controlled weight-loss trial in adults with obesity who were actively trying to lose weight. Enrolment was limited to new adult patients at the University of Alabama at Birmingham (UAB) Hospital. Patients were eligible if they had a body mass index (BMI) between 30.0 and 60.0 kg/m², were aged 25–75 years old, not taking weight loss medication, and did not have diabetes or a severe or unstable medical condition. Patients were excluded if they regularly ate less than 10 h daily, ate dinner before 18:00, performed overnight shift work, or planned to travel across more than one-time zone. A description of recruitment methods and a complete list of the eligibility criteria are provided in the primary manuscript [30]. The co-primary outcomes were weight loss and fat loss as measured by Dual X-ray Absorptiometry. The secondary outcomes were fasting cardiometabolic risk factors. Additional outcomes included adherence, satisfaction with the eating windows, food intake, physical activity, mood, and sleep. Participants reported when they started and stopped eating daily through surveys administered via REDCap (Research Electronic Data Capture) software [49, 50]. The study was approved by UAB’s Institutional Review Board (protocol number 300001207). All participants provided written informed consent prior to participating.

2.2 |. Intervention Arms

Participants were randomised to either eTRE, with an 8-h window from 07:00 to 15:00, or the control schedule allowing eating over ≥ 12 h per day. Both groups were instructed to follow their assigned eating schedule at least 6 days/week. Participants were randomised in a 1:1 ratio, with stratification by biological sex, race, and physical activity status (≤ 2 days/week vs. ≥ 3 days/week of any exercise). Both groups received lifestyle counselling through the Weight Loss Medicine Clinic, which included four one-on-one meetings with a registered dietitian guiding them to reduce energy intake and increase physical activity. Participants were also required to attend at least 10 classes explaining diet, exercise, and behavioural modification. Further details are provided in the primary manuscript [30].

2.3 |. Exit Interview

At the end of the 14-week intervention, we conducted semi-structured exit interviews probing participants’ experiences adhering to their assigned eating schedule. Interviews were conducted by the study coordinators during the morning on the final day of testing. The only notable exception was about a dozen participants who completed their interviews over the phone due to either dropping out of the study or the COVID-19 pandemic. Interviews were audio recorded and transcribed later. Although participants in both groups were required to enrol in a weight loss programme, the exit interview specifically focused only on the feasibility of following the prescribed meal timing schedules. The semi-structured interview included questions such as: Is there anything that helped you follow your eating schedule? Is there anything that made it difficult to follow your eating schedule? Were you able to overcome these difficulties, and if so, how? What would you recommend to make this eating schedule more doable for other people? Do you have suggestions for adapting or improving your eating schedule? It also queried participants about how their assigned eating schedule affected their social life, family obligations and relationships, social relationships, job and relationships with coworkers, and hobbies and personal time. All interview questions were designed to be open-ended and broad to encourage participants to elaborate on their responses. Interviews typically lasted between 10 and 20 min.

2.4 |. Data Analysis

The audio recordings were transcribed by the professional transcription service Ubiquis (New York, NY). To facilitate data management, transcripts were entered into MAXQDA 2020 (VERBI Software, 2019). Data were analyzed using thematic analysis based on Braun and Clarke’s six-phase procedure [51]. To increase reliability and reduce bias, the interviewers did not take part in the analysis, and transcripts were coded by the first author, who was blinded to arm assignment [52]. Transcripts were read and reread for familiarisation by the first author, who independently coded transcripts and developed a final coding frame through discussion with co-authors. Coding continued until no new codes were identified from the data. Next, the primary author derived initial themes and subthemes. Final themes were derived after further interpretation, familiarisation with the data, and consideration of the aims by all authors.

3 |. Results and Discussion

Ninety participants enroled in the study. The eTRE group adhered to 6.0 ± 0.8 days/week, while the control group adhered to 6.3 ± 0.8 days/week [30]. Seventy-one participants completed semi-structured interviews (eTRE: n = 34, Control: n = 37), including two participants who withdrew from the eTRE group and one from the control group. Exit interview participants were aged 43 ± 11 years, had a BMI of 38.7 ± 6.3 kg/m², were 82% female, and were 30% Black or African American (Table 1). No differences by age or sex were observed in the analyses of cardiometabolic risk factors (manuscript forthcoming). In the exit interviews, we did not observe any notable differences by age or sex; other environmental, occupational, and behavioural factors appeared more influential. Thematic analysis identified several key themes and subthemes (described below) that characterised participants’ experiences of facilitators and barriers in both intervention groups (Figure 1).

TABLE 1 |.

Baseline characteristics. Mean ± SD.

	Total (N = 71)	CON (N = 37)	eTRE (N = 34)	p
Demographics
Age (years)	43 ± 11	43 ± 12	44 ± 10	0.77
Female (%)	82%	81%	82%	1.00
Race (%)				1.00
Black or African American	30%	30%	29%
Not Black or African American	70%	70%	71%
Ethnicity (%)				0.25
Not Hispanic or Latino	93%	89%	97%
Hispanic or Latino	3%	3%	3%
Unknown or not reported	4%	8%	0%
Anthropometrics
Weight (kg)	106.8 ± 21.3	103.3 ± 21.3	110.7 ± 21	0.15
BMI (kg/m2)	38.7 ± 6.3	38.0 ± 5.9	39.5 ± 6.8	0.31
Eating habits
Eating duration (hours/day)	12.60 ± 1.52	12.81 ± 1.70	12.38 ± 1.29	0.24
Fasting duration (hours/day)	11.40 ± 1.52	11.19 ± 1.70	11.62 ± 1.29	0.24
Eating start time (hh:mm)	7:31 ± 1:05	7:31 ± 1:10	7:31 ± 1:01	0.96
Eating end time (hh:mm)	20:07 ± 1:25	20:19 ± 1:41	19:54 ± 1:03	0.21
Eating midpoint (hh:mm)	13:49 ± 1:00	13:55 ± 1:10	13:43 ± 0:48	0.40

Abbreviations: BMI = body mass index, CON = control eating schedule, eTRE = early time-restricted eating.

FIGURE 1 |.

Facilitators and barriers that mainly affect adherence to eTRE (purple font) versus meal timing interventions in general (black font).

3.1 |. Facilitators of Adherence

3.1.1 |. Perceived Health Benefits

More than half of the participants in each group reported experiencing health benefits due to the intervention, which motivated them to adhere to their assigned group. Many participants described their joy in successfully losing weight and feeling energetic. For example, one participant in the control group enthused:

“I’m losing weight and still feel energetic. And I can continue this for a long time.”

Both groups reported that physical health improvements motivated them to continue following their eating schedule. Participants in both groups also reported mental benefits such as “feeling better” or being “happier.” One eTRE participant remarked:

“I’ve definitely learned how to eat a lot healthier, and it’s so simple and so easy once you put your mind to it. That’s one of the best ways, honestly. And it’s helped me be happier with myself.”

Positive changes in physical and mental health, such as improved mood and increased energy, have been linked to sustained motivation and adherence [53].

As a third health benefit, participants also highlighted that increased awareness of the time allocated to eating improved their relationship with food, making them more conscious of the types of food they were eating. Having an eating schedule helped them practice more mindful eating. For instance, one eTRE participant reported:

“[Doing eTRE helped me] make healthier [food] choices and just being conscious of when I’m eating and what I’m eating.”

This was echoed by another eTRE participant:

“My eating schedule made me much more mindful of what I was eating, when I was eating, my mood that I was eating in.”

Emerging research suggests that mindful eating is associated with higher diet quality and better eating behaviours, such as slowing the pace of eating, Control overeating, and opting for smaller sizes of calorie-dense foods [54, 55].

3.2 |. Meal Planning

Nearly half of participants in the eTRE group and a handful of participants in the control group reported that planning and/or prepping meals and snacks in advance were helpful tools. For eTRE participants, meal planning prevented missing a meal. Most eTRE participants were at work when their eating window ended on workdays, so meal planning ensured they could eat dinner before their eating window closed. This was illustrated in the following remarks from an eTRE participant:

“Meal prepping every week helped. I had to make sure that I packed my food for the day for work because my work schedule is 8:00 to 4:30, so I was like, well, there’s my whole day. And if I didn’t have everything with me, it made it hard to stay on the schedule.”

Some eTRE participants planned each individual meal and snack. This ensured they consumed enough food during their eating window, which prevented becoming too hungry and reduced the likelihood of eating outside their window. One eTRE participant described this as:

“Planning and thinking through what snacks I needed to be eating, when I needed to be eating, and making a plan in the morning…so that way I had it kind of figured out already, and it wasn’t like 2:55, and I had forgotten to eat and had to rush to eat something.”

A small number of control participants also planned their meals in advance. For control participants, meal planning helped control portion sizes, prevent overeating, and reduce hunger. For example, one control participant explained how planning each meal in advance helped her spread her meals and snacks across ≥ 12 h:

“Just to make sure you have an eating plan, what you’re gonna eat, too, and have a time throughout the day… not just I’m gonna start at one time and end at one time. Make sure you know through the day when you’re gonna eat, too, so you space out the times.”

Planning and preparing meals and snacks in advance has been linked to better adherence to nutritional guidelines and lower odds of obesity [56]. In our study, meal prepping reduced the cognitive load, allowing participants to focus on maintaining a consistent eating schedule. These findings are consistent with previous meal timing studies, highlighting the benefits of action plans in structuring eating and fasting windows to improve adherence [41, 45].

3.3 |. Reminders via Commitment Devices

Participants in both groups frequently used timers or other commitment devices (e.g., smartphones, alarms) to remind them to eat within their eating schedule. A commitment device is a tool or strategy that helps individuals stick to their goals by aligning short-term actions with long-term interests. This theme emerged more clearly among eTRE participants, with nearly a third reporting that they used phone timers, alarms, phone apps, or other tools to either remind themselves when to eat meals and snacks and/or to signal the start and end of their eating window. One eTRE participant described using an alarm on their cell phone “every time it was mealtime.” Another eTRE participant stated the “timer on my phone [was the] number one thing that helped me.” Other participants relied on phone apps to ensure they ate dinner before their window closed. One eTRE participant stated:

“My Fitness Pal helped me. I use alarms to make sure I knew what time it was. If I was 30 minutes from my three o’clock out, [my phone] would chime, have you had your dinner? And so, I would definitely say alarms help me. My Fitness Pal helped me.”

Timers were also used to prevent participants from losing track of time. Studies on other TRE windows have also reported reminders via commitment devices are a key facilitator, regardless of the time of day of the eating window [44, 57]. One eTRE participant stated:

“I would set timers so I wouldn’t forget [to eat] because sometimes at work, I have classes. I teach classes and I would let time slide by, so I had to start using a timer all the time.”

Nearly a dozen participants in each group also indicated that the daily adherence surveys served as a helpful reminder. The daily surveys were programmed to be sent out around 2:30 PM every day to remind eTRE participants their eating window was closing in 30 min.

Though we did not require our participants to use commitment devices, other TRE trials have required participants to use phone apps, written/electronic journals, or daily food diaries, which likely increased adherence [44, 57, 58]. Commitment devices are a valuable tool in TRE interventions, helping individuals stay mindful of eating times and avoid unintentional non-adherence [59].

3.4 |. Accountability

About one-third of participants in each group indicated that reporting their daily adherence helped them adhere. The surveys made participants feel accountable to the research staff. A control participant stated that the survey:

“Kept me accountable, and it got me in a routine, so I feel like that was very beneficial.”

By reporting when they started and stopped eating each day, participants also became more aware of their actions, which reinforced positive behaviours and helped them get into a routine. For other participants, having to tell someone when they ate was a deterrent to eating outside their assigned window. For example, one eTRE participant revealed:

“[I] hated [the surveys], but the e-mail reminders were the constant [reminder that] you still have to answer that e-mail. Better not mess it up. Don’t eat ‘cause’ you’re gonna have to tell somebody if you do. So the guilt factor is good.”

These findings are consistent with the broader weight management literature supporting the role of both self-monitoring and social accountability in sustaining adherence to lifestyle interventions.

3.5 |. Factors That Can Serve as Either Facilitators or Barriers

3.5.1 |. Break Days, Weekends, and Special Occasions

Participants were counselled to follow their eating schedule at least 6 days/week and were allowed one break day per week. None of the participants in the control group mentioned break days as either facilitators or barriers. By comparison, one-third of eTRE participants described break days as “helpful” or “nice.” Many eTRE participants enjoyed having break days to share meals with family and friends or to partake in social activities involving food. For example, an eTRE participant described their break day as:

“Nice because that’s one day a week you can, you know, go out and enjoy with family or whatever the case may be.”

In these situations, having break days offered psychological relief and re-ignited motivation. In previous trials [37, 42, 60], providing break days was found to enhance motivation to sustain the dietary intervention, satisfy cravings, and support long-term adherence.

While break days were generally seen positively, some eTRE participants felt that break days made it hard to get back on track. For example, one eTRE participant explained:

“I did it for the holidays, and then there was a birthday dinner here or there, but I did it only on special occasions because trying to do it every week…the first time I did it was very challenging to get back into it.”

In particular, weekends, holidays, and special events were perceived as “difficult” and “hard” among a small portion of participants in both groups. For this reason, participants often opted to take a break on the weekend, on holidays, or on the day of a special event. Two of the biggest obstacles were changes in social activities and sleep routines on these days. In particular, inconsistent sleeping patterns on weekends made it challenging for participants to follow their prescribed window, as expressed by a control participant:

“When I overslept or slept in on the weekends, sometimes it was very hard to get my time in, my food in for the 12 hours.”

Sleeping in on the weekends also delayed the start of the eating window in the eTRE group. Weekends were also challenging because of the lack of a consistent routine or structured time—which is often reported as a barrier to adopting positive health behaviours in general. This was exemplified by an eTRE participant:

“A lot of times, I wouldn’t know what our day was going to be like because the weeks were so structured, but weekends aren’t, so it was a little harder to plan what time to eat and what to eat when.”

Altogether, our findings align with previous TRE trials indicating that break days or changes in routine facilitate adherence for some individuals [42, 44, 45, 57, 61], yet can be disruptive for other individuals, making it difficult to sustain adherence [57, 62].

3.5.2 |. Social Support and Relationships

A small fraction of participants in both groups mentioned that support from loved ones was instrumental in helping them stick to their meal timing schedule, with more participants in the eTRE group reporting this as a key factor. Family and friends supported participants by encouraging them, celebrating their successes, acknowledging their efforts, and/or holding them accountable. Other types of support were more tangible, such as sharing responsibility for cooking or preparing meals or changing one’s eating times to align with participants. In the eTRE group, one participant said that “getting moral support and encouragement from friends and family” was one of the most important factors that helped him follow eTRE. In the control group, a participant explained that her husband supported her eating schedule by cooking:

“His willingness to just fix a snack and cook. His willingness to cook for me because I’m a snacker while I cook […] When he got home, he was more willing to cook supper to help me stay within the guidelines.”

Family members also supported participants by shifting their mealtimes—mainly to eat an earlier dinner—or eating lunch together instead of dinner to remove temptation or accommodate a participant’s eating schedule. One eTRE participant stated:

“My family, they basically started, made sure they were done eating before I got home […] So, it worked out really good.”

However, family and loved ones were not always perceived as supportive. In the eTRE group, a small number of participants described their family members’ unwillingness to modify their eating habits as an obstacle. Other perceived barriers among eTRE participants included family members visibly eating in front of the individual or expecting the individual to cook family meals after the individual’s eating window ended. A participant in the eTRE group described how her husband’s eating habits tempted her to eat past 15:00:

“My husband has a habit of eating in the bedroom where I am, and I kind of get a little upset with him thinking: if you know that I can’t eat after three, why are you bringing this around me where I’m smelling it and wanting it?”

Thus, social support from family and loved ones can be a double-edged sword. When positive and supportive, it creates an environment that fosters motivation, consistency, and accountability. When either lacking or deliberately antagonistic, it can create obstacles and temptations, discouraging adherence.

3.6 |. Barriers to Adherence

3.6.1 |. Disruptions to Family Life

Conflicts between eating schedules and family life were seen as a key barrier. Over half of the participants in the eTRE group and one participant in the control group reported that not being able to eat with their families in the evening was challenging. One eTRE participant stated:

“So not being able to eat with all the social and family interactions in the evening was the hardest thing about the schedule.”

Needing to eat an early dinner disrupted family routines, leading to a loss of shared mealtime experiences. Another participant in the eTRE group described a similar experience:

“The family part is such an important part, and so everything else, you know, I can get over eating eight hours and fasting 16, and I can get over eating at my desk [while at work]…but the fact that it affected that kind of time we’ve spent together as a family is a huge consideration for me.”

Consistent with other TRE studies [42, 43, 57, 60], our participants reported that not sharing a meal with family was a greater challenge than prolonged fasting or eating meals alone at work. This is not surprising as sharing meals with family or friends has been linked to more social connections and emotional support [63], reduced stress, and higher levels of family functioning. One systematic review of TRE trials found that social events such as family meals, nighttime dining, social drinking, and hosting friends were a barrier to practicing TRE in 8 out of 10 trials [57]. However, this challenge is not unique to TRE: social events centred around food and drink are barriers to making dietary improvements generally (De Leon et al. 2020; Helland and Nordbotten 2021).

Additionally, trying to join family meals while not eating created uncomfortable situations. One participant in the TRE group recounted:

“Well, on some instances, I have my grandkids and my children sometimes, and we like to go out to eat in the evenings every once in a while, so I was not able to do that having to go with me after 3:00. So, I had to make adjustments to that. And it makes you feel a little awkward when you can be with people, but then you can’t enjoy what they’re doing. You can’t participate, and then you have to explain why.”

This highlights that being a non-eating observer can create discomfort among both eaters and non-eaters, making this an additional social obstacle.

3.6.2 |. Disruptions to Social Life

More than half of the eTRE group and a small fraction of the control group indicated their eating schedule disrupted social activities with friends and colleagues. The fixed eating window made it challenging to participate in social events involving food while resisting the temptation to eat. eTRE participants frequently skipped such gatherings in order to adhere to their eating schedules. One eTRE participant explained:

“[Because of eTRE], anytime friends or colleagues get together after hours, I have to pass on those events, just so I won’t be tempted to eat after the 3:00 pm mealtime.”

Balancing eating schedules with participation in social events was a recurring theme among eTRE participants. Participants from both groups reported dining out less often with coworkers to stay within their prescribed eating schedules. As one eTRE participant stated: “I did go out to eat less at work. Actually, not at all.”

Following a fixed eating schedule can make it challenging to navigate both social and professional activities. Our results are consistent with other meal timing studies, suggesting that disruptions to social and family life are barriers to adhering to meal timing interventions [43, 47, 64].

3.7 |. Intention to Continue Following Eating Schedule

Most participants in both groups reported they intended to continue their assigned eating schedule, with modifications to better suit their lifestyle. Some participants indicated they would change the number of days they followed their meal timing schedule, typically intending to follow their assigned schedule either 5 days/week (2 break days) or 7 days/week (0 break days). About a quarter of participants in the eTRE group described modifying the timing of their eating window to mid-day or late TRE. Some eTRE participants described wanting a later start or end time because they were not typically hungry at 07:00 (eating window start time for eTRE group), and either delaying or lengthening the window would allow them to have dinner with family/loved ones or partake in evening social gatherings. One participant in the eTRE group stated:

“I just wanted to maybe space out my meals a little more, like the latest I could eat is 5:00 pm just because I would like to go out with some of my new friends for margaritas after work.”

Another eTRE group participant indicated she would include the following:

“A little bit more flexibility in the schedule as far as eating a meal with the family.”

Control group participants also described wanting to adjust their eating schedules to shorten the eating window to end earlier. The ≥ 12-h eating period resulted in some participants delaying or pushing their dinner into the late evening, which was perceived as too late and not optimal. One participant in the control group said:

“I think sometimes dinner for me, like if I ate breakfast at 8 o’clock and then that made dinner having to be around 8 o’clock, that was a little late for me. So moving forward, I would back it up just a little bit.”

The majority of participants in both groups expressed wanting more flexibility in the eating schedule to be able to share meals with loved ones or colleagues and accommodate social life activities. Our findings align with previous meal timing studies, which suggest some flexibility in eating schedules can mitigate some of the perceived social and lifestyle barriers to adherence and sustainability [41, 42, 44].

4 |. Conclusion

Our qualitative analysis highlights key facilitators and barriers to adhering to eTRE, with perceived health benefits, meal planning, commitment devices, and accountability serving as facilitators, while disruptions to family and social life posed significant challenges. These findings align with previous research that meal planning, commitment devices, accountability, mindfulness, and social influences affect adherence to dietary interventions [41, 42, 54, 55, 60, 65, 66].

Key strengths of this study are its use of a large sample size for qualitative research and its comprehensive exploration of participants’ experiences. Additionally, this is the first qualitative study to incorporate a control group, allowing for a nuanced comparison of factors unique to eTRE. We found that meal planning and commitment devices were used as tools much more often in the eTRE group, with about one-half and one-third of eTRE participants using these strategies, respectively. Additionally, break days, inconsistent routines, and social relationships acted as facilitators or barriers, depending on the person.

Collectively, these results suggest that TRE interventions should help participants develop strategies to resolve conflicts between eating schedules and family and social life. Moreover, they should consider allowing more flexibility in the eating windows, such as to accommodate weekends and social events. Tailored strategies, such as allowing occasional deviation or providing commitment devices, may enhance adherence and promote long-term adoption [1, 42, 66, 67]. Programmes emphasising the psychological benefits of TRE, such as improved mood and self-efficacy, may also support sustained behavioural change.

This study has limitations, including its reliance on self-reported adherence and the relatively short intervention period. Future research should explore adherence over longer durations and across populations with greater gender diversity to improve generalisability. Additionally, the study’s focus on eTRE may not fully capture the experiences of those adhering to other eating windows, which could influence facilitators and barriers. Finally, we cannot rule out that response bias or sampling bias affected our findings.

Despite the barriers, most participants were motivated enough to continue practicing TRE either as prescribed in our study or in a modified form that would give them more flexibility to partake in family and social activities, such as following the schedule 5 days/week or ending the eating window later in the day. Future studies should investigate interventions combining flexible timing or a flexible number of break days with other adherence-enhancing strategies, such as social support mechanisms or technology-based reminders.

Supplementary Material

Interview Questions

Supplementary Table S1: Exit Interview Questions.

Additional supporting information can be found online in the Supporting Information section.

Summary.

• Participants found early time-restricted eating generally manageable, but adherence depended on daily routines, social commitments, and personal motivation.

• Planning meals, using reminders, and focusing on health benefits supported adherence, while disruptions to family and social life were the main challenges.

• Many participants intended to continue time-restricted eating after the study, often with modifications to make it easier to sustain.

Data Availability Statement

Data will be available upon reasonable request to the corresponding author starting in 2025.