Abstract
BACKGROUND: Dietary interventions, particularly intermittent fasting (IF) and energy restriction (ER), have emerged as effective strategies for managing weight. OBJECTIVE: We aimed to conduct a systematic review and meta-analysis exploring the effects of IF and ER on body weight and cardiometabolic factors. METHODS: PRISMA compliant methods were used, and PubMed and the Cochrane CENTRAL Library were systematically searched for relevant randomized controlled trials (RCTs) from database inception to September 27, 2023. A bibliographic and gray literature search was also performed to identify unpublished literature. Effect sizes were pooled with random effects models in the R package "meta" and are reported as mean differences with 95 % confidence intervals. The quality of the included studies was assessed with The Cochrane Risk of Bias assessment tool. RESULTS: A total of 2931 records were identified through a database search. The study included 17 publications: 16 RCTs identified after two stages of screening and an additional publication identified from a bibliographic search. All trials were published between 2011 and 2022, and included a total of 1258 participants (24-209 per study). Pooled analysis revealed that IF led to a more significant decrease in BMI than ER (-0.44 [-0.88 to -0.01]; p < 0.01). Additionally, IF resulted in a slightly greater, but statistically nonsignificant, decrease in weight, triglyceride levels, fasting plasma glucose, and diastolic blood pressure than ER. However, similar decreases in SBP, LDL, and HDL levels were observed between IF and ER, which showed no major differences. The ER group experienced a higher frequency of headaches than the IF group, whereas the IF group reported a greater occurrence of dizziness than the ER group. CONCLUSION: IF appears to be slightly advantageous over ER in terms of body weight, cardiometabolic factors, and plasma glucose levels.