The current obesity epidemic is staggering in terms of its magnitude and public health impact. Current guidelines recommend continuous energy restriction (CER) along with a comprehensive lifestyle intervention as the cornerstone of obesity treatment, yet this approach produces modest weight loss on average. Recently, there has been increased interest in identifying alternative dietary weight loss strategies that involve restricting energy intake to certain periods of the day or prolonging the fasting interval between meals (i.e., intermittent energy restriction, IER). These strategies include intermittent fasting (IMF; >60% energy restriction on 2–3 days per week, or on alternate days) and time-restricted feeding (TRF; limiting the daily period of food intake to 8–10 h or less on most days of the week). Here, we summarize the current evidence for IER regimens as treatments for overweight and obesity. Specifically, we review randomized trials of ≥8 weeks in duration performed in adults with overweight or obesity (BMI ≥ 25 kg/m2) in which an IER paradigm (IMF or TRF) was compared to CER, with the primary outcome being weight loss. Overall, the available evidence suggests that IER paradigms produce equivalent weight loss when compared to CER, with 9 out of 11 studies reviewed showing no differences between groups in weight or body fat loss.

Objective: This trial aimed to evaluate the acceptability and efficacy of early timerestricted eating plus daily caloric restriction (E-TRE+DCR) compared with DCR alone within a behavioral weight-loss intervention. Methods: Participants (n = 81, 69 women, mean [SD] age: 38.0 [7.8] years, BMI: 34.1 [5.7] kg/m 2 ) were randomized to E-TRE (10-hour eating window starting within 3 hours of waking) plus DCR or DCR alone (~35% DCR) for 39 weeks. The primary outcome was body weight (measured with digital scale) at week 12. Secondary outcomes measured at week 12 included hemoglobin A1c, lipids, energy intake (photographic food records), physical activity (accelerometry), dietary adherence (questionnaires), and body composition (dual-energy x-ray absorptiometry). Weight and body composition were also assessed at week 39. Results: Mean [SD] weight loss was not different between groups at week 12

These results suggest that in prediabetic adults, acute exercise has an immediate and intensity-dependent effect on improving postprandial glycemia and insulin sensitivity.