Intermittent Fasting May Promote Weight Loss and Improve Heart Health in Obese Patients, Study Finds
Recent research from Spain suggests that intermittent fasting could be an effective strategy for weight reduction and cardiovascular health improvement among individuals dealing with obesity. Published in the esteemed journal Nature Medicine, this new study sheds light on how different fasting schedules might influence health markers and fat distribution.
Understanding Intermittent Fasting
Intermittent fasting involves eating during specific windows of time, with periods of abstaining from food—strict fasting—alternating with periods of normal or healthy eating. It’s not about what foods you eat but rather when you eat, emphasizing the timing of meals within a daily or weekly schedule.
Typically, the classic form of intermittent fasting reduces the number of hours during which eating occurs, extending the fasting duration from the standard 12-14 hours down to about 6-8 hours. This approach is supported by numerous studies showing potential benefits related to longevity. It also appears promising for managing obesity and its associated health issues, notably cardiovascular problems.
Despite its growing popularity, definitive evidence is still emerging. Most existing studies involve small sample sizes, but early results are encouraging. It’s especially relevant for patients with obesity, as this approach may help improve not only weight status but also other health parameters linked to heart disease.
This particular investigation involved 197 participants, thus providing preliminary but promising data. Carried out by the Spanish PROFITH research group in collaboration with the Universities of Granada and Navarra, the study offers insights into the potential benefits and safety of various fasting schedules.
Time-Restricted Eating (TRE) and Its Role
Another form of time-focused eating, known as Time-Restricted Eating (TRE), has gained attention but remains less explored. TRE involves limiting daily food intake to a consistent window—often 8 hours—while fasting for the remaining 16 hours. Unlike more comprehensive dietary regimens, the evidence linking TRE to reductions in visceral adipose tissue (VAT)—the unhealthy fat surrounding organs—is limited.
The current study digs deeper into this aspect by assigning participants to different TRE protocols, each with an 8-hour window. The schedules varied:
- Early window (e.g., 9:00 a.m. to 5:00 p.m.)
- Late window (e.g., 2:00 p.m. to 10:00 p.m.)
- Self-chosen timing, allowing participants to select their preferred hours
All participants combined these fasting routines with standard care, which included education on a Mediterranean diet and healthy lifestyle practices. The trial lasted 12 weeks and included adults aged 30-60 with overweight or obesity—half of whom were women. Participants were randomly assigned to one of the three fasting protocols.
Key Findings from the Study
Intermittent fasting demonstrated a notable advantage over simply following standard nutritional advice by resulting in an average weight loss of about 3 to 4 kilograms over three months. When focusing specifically on visceral fat, measured via MRI scans, the results revealed no significant differences among the groups—early TRE, late TRE, or self-selected schedules—compared to standard care. Percent changes in VAT ranged from minimal decreases, and all groups showed similar outcomes, suggesting that the timing of fasting may not have a direct impact on visceral fat reduction.
Notably, multiple safety considerations emerged. No serious adverse effects were reported; only five participants experienced mild side effects. Adherence rates to the TRE protocols were high, between 85% and 88%. Interestingly, regardless of the specific timing, all fasting groups experienced greater weight loss compared to those receiving only standard dietary education.
Furthermore, the group that selected an early fasting window (9:00 a.m. to 5:00 p.m.) exhibited more pronounced reductions in abdominal subcutaneous fat. These individuals also showed the most favorable blood sugar profiles throughout the day, indicating potential metabolic benefits tied to the timing of fasting.
Concluding Remarks
The data suggest that adding a TRE component—regardless of whether the eating window is in the morning, evening, or self-chosen—does not significantly enhance visceral fat reduction beyond what a traditional Mediterranean diet can achieve alone. Nonetheless, it does promote greater weight loss, which in turn can have favorable effects on cardiovascular health.
Overall, TRE appears to be a safe, well-tolerated, and feasible dietary intervention for overweight and obese adults. While these initial findings are promising, further studies with larger populations and longer follow-up periods are necessary to confirm and clarify the full extent of its benefits.
Source
Dote-Montero M, Clavero-Jimeno A, Merchán-Ramírez E, et al. Effects of early, late, and self-selected time-restricted eating on visceral adipose tissue and cardiometabolic health in participants with overweight or obesity: a randomized controlled trial. Nature Medicine, 2025. Link to the study
