A total of 2,634 articles were initially retrieved through the database searches. Detailed records from each of the five databases are provided in Table S1. After deduplicating and screening titles and abstracts, 56 full-text papers were evaluated for eligibility. Ultimately, 12 articles derived from 10 studies met the criteria for inclusion in the systematic review and meta-analysis [42,43,44,45,46,47,48,49,50,51,52,53]. The detailed selection procedure is illustrated clearly in the PRISMA flowchart shown in Fig. 1.

Flowchart of study selection

Table 1 provides an overview of the main characteristics of the twelve RCTs selected for inclusion in the meta-analysis [42,43,44,45,46,47,48,49,50,51,52,53]. Together, these studies involved a total of 616 participants, with an overall mean age of 40 ± 9 years, a mean BMI of 33.6 ± 4.8 kg/m2, and a sample that was 87.3% female. Among the 12 studies, three studies were conducted in the USA [45, 46, 49], two in Tunisia [42, 52], two in Brazil [43, 44], two in Korea [47, 53], one in Thailand [51], one in Norway [50], and one in Australia [48] with a total of 616 participants (sample size ranging from 20 to 131). Notably, Bhutani et al. [45, 46] and Batitucci et al. [43, 44] contributed two articles each, reporting on different outcomes. Intervention durations varied from 4 to 16 weeks; specifically, one study lasted 4 weeks [52], one study spanned 7 weeks [50], three studies lasted 8 weeks [43, 44, 53], six studies lasted 12 weeks [42, 45,46,47, 49, 51], and one study lasted 16 weeks [48]. In addition, one study exclusively enrolled male participants [52], five studies recruited only female participants [42,43,44, 50, 51], while the remaining six studies included participants of both sexes [45,46,47,48,49, 53]. Exercise interventions included continuous training [45, 46, 49], concurrent training [47, 51,52,53], and high-intensity interval [43, 44, 48, 50]/functional training [42]. As for IF type, two studies used TRE [42, 50], five studies used ADF [45,46,47, 49, 53], four studies performed 5:2 diet [43, 44, 48, 51] and one study used Ramadan IF [52].

In Figure S1, ten studies [42, 43, 45, 47,48,49,50,51,52,53] including 319 participants, examined body mass as an outcome. The analysis showed no significant difference between the combined intervention and IF alone (MD −0.15 kg; 95%CI [−0.84, 0.54]; P = 0.67; I2 = 0%, 95%PI [−1.20, 0.90]), and the certainty of this evidence was rated as very low. Seven studies [42, 43, 45, 47, 49, 51, 53] involving 224 participants, investigated the impact on BMI as an outcome (Figure S2). The analysis showed no significant difference between the combined intervention and IF alone (MD −0.26 kg/m2; 95%CI [−0.67, 0.15]; P = 0.21; I2 = 0%, 95%PI [−0.78, 0.25]), and the certainty of this evidence was rated as low. In terms of fat mass, the combined strategy showed a lower level (MD −0.93 kg; 95%CI [−1.69, −0.18]; P = 0.01; I2 = 27%, 95%PI [−2.39, 0.52]) compared to IF alone, supported by moderate certainty of evidence from a comprehensive analysis involving 10 studies [42, 43, 45, 47,48,49,50,51,52,53] encompassing 319 participants (Fig. 2). For fat-free mass, the analysis of nine studies [42, 43, 45, 48,49,50,