A recent investigation involving researchers from the University of Granada (UGR) has illuminated the enduring efficacy of intermittent fasting protocols in maintaining weight loss, revealing that individuals can retain the benefits of such programs for at least a year after the structured intervention concludes. This groundbreaking study, published in the esteemed journal Clinical Nutrition, meticulously tracked the progress of 99 adult participants grappling with overweight or obesity, with a balanced representation of both male and female subjects. The core finding underscores that adherence to a daily eating window confined to eight hours significantly enhanced participants’ ability to preserve their achieved weight loss compared to those who maintained broader eating periods exceeding twelve hours.
The scientific inquiry delved into the widely adopted 16:8 intermittent fasting methodology, a dietary strategy characterized by a daily fasting duration of sixteen hours, followed by an eight-hour period designated for food consumption. A crucial revelation from the study is that the persistence of weight management benefits was not contingent upon the timing of the eating window. Whether participants opted for an earlier schedule, consuming meals between 9 a.m. and 5 p.m., or a later schedule, from 1 p.m. to 9 p.m., the outcomes remained remarkably consistent. One full year post the cessation of the formal intervention, both the early and late time-restricted eating groups exhibited a substantially greater maintenance of weight reduction when juxtaposed with individuals who reverted to eating patterns spanning twelve hours or more daily. Furthermore, the participants who followed the earlier eating schedule also demonstrated a more significant reduction in their overall body fat mass. These findings collectively suggest that time-restricted eating, beyond its immediate short-term applicability, can yield physiological effects that extend well into the post-intervention period, offering a promising avenue for long-term weight management.
The comprehensive research, detailed in Clinical Nutrition, the official publication of the European Society for Clinical Nutrition and Metabolism, benefited from the collaborative expertise of scientists affiliated with the University of Granada (UGR), the Granada Institute for Biomedical Research (ibs.GRANADA), the Public University of Navarra, and the Biomedical Research Networking Center (CIBER). Over the initial twelve weeks of the study, all ninety-nine participants received comprehensive educational guidance on adopting a Mediterranean dietary pattern, a cornerstone of healthy eating. Following this foundational phase, they were strategically allocated into four distinct experimental groups.
A control group was established, tasked with continuing their customary daily eating habits, which typically involved windows of twelve hours or more. The remaining participants were assigned to specific intermittent fasting schedules. The early fasting group adhered to an eight-hour eating window commencing before 10:00 a.m., while the late fasting group implemented an eight-hour window that began after 1:00 p.m. A fourth group, designated as the self-selected group, was afforded the autonomy to choose their own eight-hour eating schedule, reflecting a more personalized approach. Throughout these phases, researchers meticulously collected data on body weight, body fat mass, and fat-free mass, conducting assessments both before and after the twelve-week intervention period. Crucially, these same measurements were re-evaluated one year after the program’s conclusion, providing a critical longitudinal perspective on the sustainability of the observed changes. These findings build upon earlier research, where primary results from a broader project, published in Nature Medicine, indicated that participants practicing time-restricted eating (TRE) achieved an average weight loss of 3-4 kilograms more than those who received only nutritional guidance, irrespective of the specific timing of their eating window.
Dr. Alba Camacho Cardeñosa, a distinguished researcher at the University Joint Institute for Sport and Health (iMUDS) at the University of Granada (UGR) and a postdoctoral fellow at ibs.GRANADA within the Endocrinology and Nutrition Department at San Cecilio University Clinical Hospital, served as the lead author of this significant study. Dr. Cardeñosa articulated the study’s primary contribution, stating, "To date, although we knew that intermittent fasting promotes modest weight loss in the short term, it was unclear whether its effects were sustained over time." She further elaborated on the study’s implications, emphasizing, "By evaluating the participants twelve months after the intervention ended, we demonstrated that the changes in body weight persist." The researchers also highlighted a particularly encouraging observation regarding the practicality and self-management potential of intermittent fasting. They noted, "A very positive finding is that one in three people decided to continue practicing intermittent fasting on their own during that year of follow-up, suggesting that it is a relatively easy habit to integrate into daily life." This finding strongly implies that intermittent fasting, when introduced effectively, can transition from a structured therapeutic intervention to a sustainable lifestyle choice for many individuals.
The research endeavor was spearheaded by the PROFITH CTS-977 research group at the University of Granada (UGR), operating under the umbrella of ibs.GRANADA, with Professor Jonatan Ruiz Ruiz at the helm. The collaborative nature of this project extended to include valuable contributions from the San Cecilio University Clinical Hospital, Virgen de las Nieves University Hospital in Granada, the Public University of Navarra, the CIBER on Obesity (CIBEROBN), and the CIBER on Frailty and Healthy Aging (CIBERFES). According to the collective insights of the research team, even a relatively brief twelve-week duration of intermittent fasting can serve as an effective medium-term strategy for weight management among adults classified as overweight or obese.
A key takeaway from the study is the inherent flexibility of time-restricted eating. The observation that both early and late eating windows yielded comparable long-term benefits empowers healthcare providers and individuals to select the schedule that best aligns with their personal routines and lifestyle preferences. This adaptability is posited to be a significant factor in enhancing adherence to intermittent fasting protocols, thereby potentially improving its overall effectiveness as a component of obesity treatment strategies. The lack of a universally superior timing for the eating window suggests that personalization is paramount for successful long-term adoption.
The research undertaken by the MP20 group, focused on Biomarkers of Metabolic and Bone Diseases at ibs.GRANADA, plays a pivotal role in advancing our understanding of metabolic, bone, and cardiovascular health. This group’s work involves the identification of biological markers and potential therapeutic targets for a spectrum of conditions. Their methodology integrates sophisticated bioinformatics with rigorous clinical research, aiming to develop diagnostic tools and rigorously assess the efficacy of novel therapies. Within this framework, the group actively investigates intermittent fasting not only as a strategy for combating obesity but also for addressing associated metabolic and cardiovascular health challenges. Furthermore, their research explores the utility of bone markers as predictive indicators of cardiovascular risk. Through its commitment to a multidisciplinary and collaborative approach, the MP20 group is dedicated to generating research findings that possess tangible and practical applications within clinical settings, ultimately contributing to improved patient outcomes and public health.
About the Author
